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Androgen regulation of the prostatic tumour suppressor NKX3.1 is mediated by its 3{'}untranslated regionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The homeodomain transcription factor NKX3.1 is a prostate-specific tumour suppressor, expression of which is reduced or undetectable in the majority of metastatic prostate tumours. In the normal prostate and in prostate cancer cells, NKX3.1 expression is under tight androgenic control that we have shown to be mediated by its ~2.5kb 3’ untranslated region (3’UTR). Reporter deletion analysis of the NKX3.1 3’UTR identified three regions that were transactivated by 5α-dihydrotestosterone (DHT) in the androgen receptor (AR)-expressing prostate cancer cell line, LNCaP. Reversal of DHT effects by the a...
Source: BJ Gene - November 3, 2009 Category: Biochemistry Authors: M A Thomas, D M Preece, J M Bentel Tags: BJ Gene Source Type: journals

Chloroplast HCF101 is a scaffold protein for [4Fe-4S] cluster assemblyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Oxygen evolving chloroplasts possess their own iron-sulfur cluster assembly proteins including members of the SUF and the NFU family. Recently, the chloroplast protein HCF101 (high chlorophyll fluorescence) has been shown to be essential for the accumulation of the membrane complex photosystem I and the soluble ferredoxin-thioredoxin reductases, both containing [4Fe-4S] clusters. The protein belongs to the FSC ([4Fe-4S]-cluster) superfamily of P-loop NTPases, several members of which play a crucial role in Fe/S cluster biosynthesis. Although the C-terminal Fe/S cluster binding site conserved in other members of the FSC fam...
Source: BJ Gene - October 8, 2009 Category: Biochemistry Authors: S Schwenkert, D J.A. Netz, J Frazzon, A J Pierik, E Bill, J Gross, R Lill, J Meurer Tags: BJ Plant Source Type: journals

Regulatory factors controlling transcription of Saccharomyces cerevisiae IXR1 (ORD1) by oxygen levels. A model of transcriptional adaptation from aerobiosis to hypoxia implicating ROX1 and IXR1 cross-regulationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study it is shown that IXR1 mRNA levels are controlled by oxygen availability, increasing during hypoxia. In aerobiosis, low levels of IXR1 expression are maintained by Rox1p repression through the general co-repressor complex Tup1-Ssn6. Ixr1p is necessary for full IXR1 expression under hypoxic conditions. Deletion analyses have identified the region in the IXR1 promoter responsible for this positive auto-control (-557 to -376). EMSA and ChIP assays show that Ixr1p binds to the IXR1 promoter both in vitro and in vivo. Ixr1p is required for hypoxic repression of ROX1 and binds to its promoter. UPC2 deletion has oppo...
Source: BJ Gene - October 5, 2009 Category: Biochemistry Authors: R Castro, M Lamas-Maceiras, P Soengas, I Carneiro, M González Siso, M Esperanza Cerdán Tags: BJ Gene Source Type: journals

PBX1 and MEIS1 up-regulate SOX3 gene expression by direct interaction with a consensus binding site within the basal promoter regionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Sox3/SOX3 is considered to be one of the earliest neural markers in vertebrates, playing a role in specifying neuronal fate. We previously reported characterization of the SOX3 promoter and demonstrated that the general transcription factors NF-Y, Sp1 and USF are involved in transcriptional regulation of SOX3 promoter activity. Here we present the first evidence that the TALE transcription factors PBX1 and MEIS1 participate in regulating human SOX3 gene expression in NT2/D1 cells by direct interaction with the consensus Pbx/Meis binding site, which is conserved in all analysed mammalian orthologue promoters. PBX1 is presen...
Source: BJ Gene - October 1, 2009 Category: Biochemistry Authors: M Mojsin, M Stevanovic Tags: BJ Gene Source Type: journals

Micro-RNA mir346 targets the 5{prime}UTR of RIP140 mRNA and up-regulates its protein expressionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Receptor-interacting protein 140 (RIP140) is a transcriptional corepressor that regulates diverse genes such as those responsive to hormones and involved in metabolic processes. The expression of RIP140 is regulated by multiple hormonal activities in adipose tissue and cancer cell lines. However, it is unclear if and how RIP140 is regulated posttranscriptionally. Using rapid amplification of 5′ complementary DNA ends (5′RACE), we have identified a novel 5′ splice variant of RIP140 mRNA in mouse brain and P19 cells. A target sequence for microRNA (miRNA) mir-346 was found in the 5′-untranslated r...
Source: BJ Gene - September 24, 2009 Category: Biochemistry Authors: N Tsai, Y Lin, L Wei Tags: BJ Gene Source Type: journals

Mutational analysis of human heat shock transcription factor 1 reveals a regulatory role for oligomerization in DNA-binding specificityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we isolated suppressors of the temperature-sensitive growth defect of hHSF1-expressing yeast cells. Intragenic suppressors contained amino acid substitutions in the DNA-binding domain of hHSF1 that enabled hHSF1 to regulate the transcription of genes containing discontinuous HSEs. The substitutions facilitated hHSF1 oligomerization, suggesting that the DNA-binding domain is important for this conformational change. Furthermore, other oligomerization-prone derivatives of hHSF1 were capable of recognizing discontinuous HSEs. These results suggest that modulation of oligomerization is important for the HSE spec...
Source: BJ Gene - September 15, 2009 Category: Biochemistry Authors: Y Takemori, Y Enoki, N Yamamoto, Y Fukai, K Adachi, H Sakurai Tags: BJ Gene Source Type: journals

Activating transcription factor 2 increases transactivation and protein stability of hypoxia-inducible factor 1 alpha in hepatocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hypoxia inducible factor-1(HIF-1) performs a crucial role in mediating hypoxia response. However, other transcription factors are also capable of regulating hypoxia-induced target gene transcription. In a previous report, we demonstrated that the transcription factor ATF-2 regulates hypoxia-induced gene transcription, along with HIF-1α. In the current study, we show that the protein stability of ATF-2 is induced by hypoxia and the hypoxia-mimic cobalt chloride (CoCl2), and that ATF-2 induction enhances HIF-1α protein stability via direct protein interaction. The knockdown of ATF-2 using siRNA and translation ...
Source: BJ Gene - August 26, 2009 Category: Biochemistry Authors: J Choi, H Cho, Y Choi, J Cheong Tags: BJ Gene Source Type: journals

The human urocortin 2 gene is regulated by hypoxia: identification of a hypoxia-responsive element in the 3{'}-flanking regionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, our study demonstrates that hypoxia induces hUcn2 expression via a specific HRE in the 3’FLR of the hUcn2 gene, which interacts with the transcription factor HIF1α. Hypoxia-mediated stimulation of cardioprotective Ucn2 may help to preserve cardiac function and prevent apoptosis in ischemic conditions in the heart. (Source: BJ Gene)
Source: BJ Gene - August 25, 2009 Category: Biochemistry Authors: K Bühler, I Plaisance, T Dieterle, M Brink Tags: BJ Gene Source Type: journals

Effect of pyruvate, lactate and insulin on ATP supply and demand in unpaced perfused rat heartEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mitochondrial respiration/oxidative phosphorylation is the main source of energy in the form of ATP in heart under physiological conditions. Different respiratory substrates were used in various experiments during heart perfusion: glucose, pyruvate, lactate, glucose + pyruvate, glucose + lactate, glucose + insulin etc. Also under physiological conditions the concentration of respiratory substrates/hormones in blood can vary significantly. In the present study we tested the effect of pyruvate, lactate and insulin (all in the presence of glucose) and glucose (in the presence of pyruvate) on the ATP-produ...
Source: BJ Gene - August 17, 2009 Category: Biochemistry Authors: B Korzeniewski, V Deschodt-Arsac, G Calmettes, G Gouspillou, J Franconi, P Diolez Tags: BJ Metabolism Source Type: journals

Functional characterization of the interactions between endosomal adaptor protein APPL1 and the NuRD co-repressor complexEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Multifunctional adaptor APPL1 protein belongs to a growing group of endocytic proteins which actively participate in various stages of signaling pathways. Due to its interaction with the small GTPase Rab5, APPL1 localizes predominantly to a subpopulation of early endosomes but is also capable of nucleocytoplasmic shuttling. Among its various binding partners, APPL1 was reported to associate with the nuclear co-repressor complex NuRD, containing nucleosome remodeling and histone deacetylase activities, but the biochemical basis or functional relevance of this interaction remained unknown. Here we characterized the binding b...
Source: BJ Gene - August 16, 2009 Category: Biochemistry Authors: M Banach-Orlowska, I Pilecka, A Torun, B Pyrzynska, M Miaczynska Tags: BJ Cell Source Type: journals

Evolution of vertebrate glucokinase regulatory protein from a bacterial N-acetylmuramate 6-phosphate etheraseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mammalian glucokinase regulatory protein (GKRP), a fructose 6-phosphate and fructose 1-phosphate sensitive inhibitor of glucokinase (GK), appears to have resulted from the duplication of a gene similar to bacterial N-acetylmuramate 6-phosphate etherase (MurQ). In the present work, we show that several genomes of primitive eukaryotes encode a GKRP-like protein with two MurQ repeats. Recombinant Haemophilus influenzae MurQ and the GKRP homologue of the amoebaflagellate Naegleria gruberi both behaved as excellent N-acetylmuramate 6-phosphate etherases, with Kcat values (83 and 20 sec-1) at least as high as that reported for E...
Source: BJ Gene - August 11, 2009 Category: Biochemistry Authors: M Veiga-da-Cunha, T Sokolova, F R. Opperdoes, E Van Schaftingen Tags: BJ Metabolism Source Type: journals

RNase R mutants elucidate the catalysis of structured RNA: RNA-binding domains select the RNAs targeted for degradationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report that Asp-280 is crucial for RNase R activity without affecting RNA binding. When Tyr-324 was changed to alanine the final product changed from 2 to 5nts showing that this residue is responsible for setting the end-product. We have shown that the RNB domain of RNase II has catalytic activity. The most striking result is that the RNase R RNB domain per se degrades double stranded substrates even in the absence of a 3’-overhang. Moreover, we demonstrate for the first time that the substrate recognition of RNase R depends on the RNA binding domains that target the degradation of RNAs that are “tagged&#x...
Source: BJ Gene - July 26, 2009 Category: Biochemistry Authors: R G. Matos, A Barbas, C M. Arraiano Tags: BJ Gene Source Type: journals

Fibulin-4 regulates the expression of the tropoelastin gene and consequent elastic fiber formation by human fibroblastsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Elastic fibers are essential for normal physiology in numerous tissues including arteries, lungs, and skin. Fibulin-4 is an elastic fiber-associated glycoprotein that is indispensable for elastic fiber formation in mice. However, the mechanism by which fibulin-4 executes this function remains to be determined. Here, we established an in vitro functional assay system in which fibulin-4 was knocked down in human foreskin fibroblasts using siRNA technology. With two different siRNAs, substantial knock down of fibulin-4 was achieved, and this suppression was associated with impaired elastic fiber formation by the fibroblasts. ...
Source: BJ Gene - July 22, 2009 Category: Biochemistry Authors: Q Chen, T Zhang, J F Roshetsky, Z Ouyang, J Essers, C Fan, Q Wang, A Hinek, E F Plow, P E. DiCorleto Tags: BJ Cell Source Type: journals

Human Ccr4-Not complexes contain variable deadenylase subunitsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we examine the composition of the human Ccr4-Not complex in an in-depth proteomic approach using stable cell lines expressing tagged CNOT proteins. We find at least four different variants of the human complex, consisting of seven stable core proteins and mutually-exclusive associated mRNA deadenylase subunits. Interestingly, human CNOT4 is in a separate ~200 kDa complex. Furthermore, analyses of associated proteins indicate involvement of Ccr4-Not complexes in splicing, transport and localization of RNA molecules. Taken together, human Ccr4-Not complexes are heterogeneous in composition due to differences i...
Source: BJ Gene - June 25, 2009 Category: Biochemistry Authors: N Lau, A Kolkman, F M.A. van Schaik, K W. Mulder, W Pim Pijnappel, A J.R. Heck, H Marc Timmers Tags: BJ Gene Source Type: journals

Functional conservation of tRNase ZL among Saccharomyces cerevisiae, Schizosaccharomyces pombe and humansEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report that both sptrz1+ and sptrz2+ are essential for growth. Moreover, sptrz1+ is required for cell viability in absence of Sla1p which is thought to be required for endonuclease-mediated maturation of pre-tRNA 3' ends in yeast. Both scTRZ1 and ELAC2 can complement a temperature sensitive allele of sptrz1+, sptrz1-1, but not the sptrz1 null mutant, indicating that despite exhibiting species specificity, tRNase ZLs are functionally conserved among S. cerevisiae, S. pombe and humans. Overexpression of sptrz1+, scTRZ1 and ELAC2 can increase suppression of the UGA nonsense mutation ade6-...
Source: BJ Gene - June 24, 2009 Category: Biochemistry Authors: Z Zhao, W Su, S Yuan, Y Huang Tags: BJ Gene Source Type: journals

A novel p53 target gene, S100A9, induces p53-dependent cellular apoptosis and mediates p53 apoptosis pathwayEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
S100A9 is a calcium-binding protein of the S100 family, and its differential expression has been associated with acute and chronic inflammation and several human cancers. Our previous work showed that S100A9 was severely down-regulated in human esophageal squamous cell carcinoma. To further investigate the transcriptional regulation of S100A9, we analyzed S100A9 promoter region and found several putative p53 binding sites (p53 BS). Luciferase reporter assay showed that the constructs carrying p53 BS exhibited enhanced luciferase activity in response to wild type p53 activation. Further study demonstrated that S100A9 mRNA a...
Source: BJ Gene - June 16, 2009 Category: Biochemistry Authors: C Li, H Chen, F Ding, Y Zhang, A Luo, M Wang, Z Liu Tags: BJ Gene Source Type: journals

P/CAF rescues Stra13 mediated repression of MyoD transactivationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recently, we found that myogenic regulatory factors (MRFs) regulated the expression of Peroxisome Proliferation Activation Receptor γ Coactivator 1α (PGC-1α) by targeting a short region (-49~+2) adjacent to the transcription initiation site that contained two E-boxes. However, only the E2-box shown significant affinity to MRFs and the E1-box was predicted to be the target of Stra13, a transcriptional repressor implicated in the regulation of several physiological processes. Using electrophoresis mobility shift assay (EMSA), we confirmed that Stra13 targeted the E1-box and formed a complex with M...
Source: BJ Gene - June 11, 2009 Category: Biochemistry Authors: S Hsiao, K Huang, H Chang, S Chen Tags: BJ Gene Source Type: journals

NCU-G1 is a highly glycosylated integral membrane protein of the lysosomeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Until recently, a modest number of approximately 40 lysosomal membrane proteins had been identified and even fewer were characterized in their function. In a proteomic study, using lysosomal membranes from human placenta we identified several candidate lysosomal membrane proteins and proved the lysosomal localization of two of them. Here, we demonstrate the lysosomal localization of the mouse ortholog of the human C1orf85 protein that had been termed kidney predominant protein NCU-G1 (Acc.No: AB027141). NCU-G1 encodes a 404 amino acid protein with a calculated molecular mass of 39 kDa. The bioinformatics analysis of its am...
Source: BJ Gene - June 2, 2009 Category: Biochemistry Authors: O Schieweck, M Damme, B Schröder, A Hasilik, B Schmidt, T Lübke Tags: BJ Cell Source Type: journals

Spermine analogs regulated expression of spermidine/spermine N1-acetyltransferase and its effects on depletion of intracellular polyamine pools in mouse fetal fibroblastsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the regulation of SSAT by spermine analogs, the inducers of the enzyme, was studied in the wild-type mouse fetal fibroblasts expressing endogenous SSAT and in the SSAT-deficient mouse fetal fibroblasts transiently expressing the SSAT- EGFP (enhanced green fluorescent protein) fusion gene. In both cell lines treatments with DENSpm (N1, N11 –bis(ethyl)norspermine), CPENSpm (N1-ethyl-N11-((cyclopropyl)methyl)-4,8-diazaundecane) and CHENSpm (N1-ethyl-N11-((cycloheptyl)methyl)-4,8-diazaundecane) led to high, moderate or low induction of SSAT activity, respectively. The detected levels of activities correla...
Source: BJ Gene - May 27, 2009 Category: Biochemistry Authors: A Uimari, T A Keinänen, A Karppinen, P Woster, P Uimari, J Jänne, L Alhonen Tags: BJ BJ Gene Source Type: journals

Elevated levels of IL-1{beta} in Fanconi Anemia group A patients due to a constitutively active PI3K-AKT pathway are capable of promoting tumor cell proliferationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Fanconi Anemia is a hereditary disease characterized by congenital malformations, progressive bone marrow failure and an extraordinary elevated predisposition to develop cancer. In the present article we describe an anomalous high level of the proinflammatory cytokine IL-1β present in the serum of Fanconi Anemia patients. The elevated levels of IL-1β were completely reverted by transduction of a wild type copy of the FancA cDNA into FA-A lymphocytes. Although the transcription factor NF-κB is a well established regulator of IL-1β expression, our experiments did not show any proof of elevated NF-...
Source: BJ Gene - May 27, 2009 Category: Biochemistry Authors: A Ibáñez, P Río, J Antonio Casado, J Antonio Bueren, J Luis Fernández-Luna, C Pipaón Tags: BJ BJ Gene Source Type: journals

A novel function of Aft1 in regulating ferrioxamine B (FOB) uptake; Aft1 modulates Arn3 ubiquitination in Saccharomyces cerevisiaeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Aft1 is a transcriptional activator in Saccharomyces cerevisiae that responds to iron availability and regulates the expression of genes in the iron regulon, such as FET3, FTR1, and the ARN family. Using a two-hybrid screen, we found that Aft1 physically interacts with the ferrioxamine B (FOB) transporter Arn3. This interaction modulates the ability of Arn3 to take up FOB. The interaction between Arn3 and Aft1 was confirmed by β-galactosidase, co-immunoprecipitation, and surface plasmon resonance (SPR) assays. Truncated Aft1 interacted more strongly with Arn3 and caused a higher FOB-uptake activity than full-length ...
Source: BJ Gene - May 26, 2009 Category: Biochemistry Authors: M Jeong, C Kang, J Kim, D Heo, M Chang, I Baek, H Ro, I Choi, T Kim, C Yun Tags: BJ BJ Gene Source Type: journals

Overexpression of Drosophila mitoferrin in l(2)mbn cells results in dysregulation of Fer1HCH expressionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mrs3p and Mrs4p (Mrs3/4p) are mitochondrial iron carrier proteins that play important roles in iron-sulphur cluster (ISC) and haem biosynthesis. At low iron conditions mitochondrial and cytoplasmic ISC protein maturation is correlated with MRS3/4 expression. Zebrafish mitoferrin1 (mfrn1), one of two MRS3/4 orthologues, is essential for erythropoiesis. Little is known about the ubiquitously expressed paralogue mfrn2. We identified only one mitoferrin gene (dmfrn) in the genome of Drosophila melanogaster; moste likely an orthologue of mfrn2. Overexpression of dmfrn in the Drosophila l(2)mbn cell line (mbn-dmfrn) resulted in ...
Source: BJ Gene - May 19, 2009 Category: Biochemistry Authors: C Metzendorf, W Wu, M I. Lind Tags: BJ BJ Cell Source Type: journals

Sumoylation enhances DNA methyltransferase 1 activityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
DNA methylation regulates gene expression through a complex network of protein/protein and protein/DNA interactions in chromatin. The maintenance methylase, DNA methyltransferase 1 (DNMT1), is a prominent enzyme in the process that is linked to DNA replication and drives the heritable nature of epigenetic modifications. The mechanistic details that explain how DNMT1 catalytic action is directed and regulated in chromatin are important in our overall understanding of gene control. In this work, we show that DNMT1 is modified by sumoylation and we have mapped these sumoylation sites by defined mutations. Sumoylated DNMT1 is ...
Source: BJ Gene - May 18, 2009 Category: Biochemistry Authors: B Lee, M T Muller Tags: BJ BJ Cell Source Type: journals

Hsp70 is required for optimal cell proliferation in mouse A6 mesoangioblast stem cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mouse Hsp70 is preferentially induced by heat or stress stimuli. We previously found that Hsp70 is constitutively expressed in A6 mouse mesoangioblast stem cells, but its possible role in these cells and the control of its basal transcription remained unexplored. Here we report that in the absence of stress, Ku factor is able to bind the heat shock element (HSE) consensus sequence in vitro, and in vivo it is bound to the proximal hsp70 promoter. In addition, we show that constitutive hsp70 transcription depends on the cooperative interaction of different factors such as Sp1 and GAGA binding protein with Ku factor, which bi...
Source: BJ Gene - May 1, 2009 Category: Biochemistry Authors: G Turturici, F Geraci, M E Candela, G Cossu, G Giudice, G Sconzo Tags: BJ BJ Cell Source Type: journals

Characterization of protein arginine methyltransferase I from Plasmodium falciparumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Arginine methylation is a posttranslational modification that affects many cellular processes in eukaryotes. The malaria parasite Plasmodium falciparum encodes three conserved protein arginine methyltransferases (PfPRMTs). We have determined that PfPRMT1 had authentic type I PRMT activity to form monomethylarginines and asymmetric dimethylarginines. Compared to mammalian PRMT1s, PfPRMT1 possesses a distinctive, ~50 amino acids longer N-terminal sequence, which is essential for enzyme activity. Recombinant PfPRMT1 methylated histones H4 and H2A, and several conserved substrates involved in RNA metabolism, including fibrilla...
Source: BJ Gene - April 3, 2009 Category: Biochemistry Authors: Q Fan, J Miao, L Cui, L Cui Tags: BJ Disease Source Type: journals

Drosophila expresses a CD98 transporter with evolutionarily conserved structure and amino acid transport propertiesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mammalian CD98 heterodimeric amino acid transporters consist of a promiscuous single-pass transmembrane glycoprotein, CD98hc, the ‘heavy chain’, and one of six multipass transmembrane proteins, or ‘light chains’. The heterodimeric complexes of CD98hc and the light chains LAT1 or LAT2 specifically promote sodium-independent System L exchange of neutral amino acids, including leucine. CD98hc is also implicated in other processes, including cell fusion, cell adhesion and activation of TOR signalling. Recent reports surprisingly suggested that insects lack a membrane-bound CD98hc, but here we show t...
Source: BJ Gene - April 1, 2009 Category: Biochemistry Authors: B Reynolds, P Roversi, R Laynes, S Kazi, R Boyd, D C. I. Goberdhan Tags: BJ Cell Source Type: journals

Kr{u}ppel-like factor 4 (KLF4) positively regulates human ghrelin expressionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ghrelin, an endogenous ligand of the GH secretagogue receptor, influences many metabolic processes including GH secretion, food intake, energy balance, insulin secretion, and adipogenesis. Although ghrelin exhibits a variety of biological functions, the mechanism by which ghrelin expression is regulated is unknown. Ghrelin is expressed in the gastrointestinal tract, predominantly the stomach, as is Krüppel-like factor 4 (KLF4). Therefore, we investigated whether ghrelin expression is associated with KLF4. We found that the tissue distribution of ghrelin was in accordance with that of KLF4. Furthermore, treatment wit...
Source: BJ Gene - March 27, 2009 Category: Biochemistry Authors: H Lee, Y Kang, C Moon, M Joe, J Lim, Y Seo, J Song, M Jung Tags: BJ Gene Source Type: journals

Desmosterol can replace cholesterol in sustaining cell proliferation and regulating the SREBP pathway in a sterol-{Delta}24-reductase deficient cell lineEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cholesterol homeostasis is critical for cell viability and proliferation. The sterol regulatory element-binding protein (SREBP) pathway is crucial for the maintenance of cholesterol homeostasis. This pathway is controlled by cholesterol and cholesterol-derived oxysterols. J774 cells cannot convert desmosterol into cholesterol, a defect resulting from the absence of mRNA for sterol-Δ24-reductase. Using J774 cells, we addressed the capacity of desmosterol to replace cholesterol in sustaining cell proliferation and regulating the SREBP pathway. J774 cells were able to grow indefinitely after the virtually total replace...
Source: BJ Gene - March 5, 2009 Category: Biochemistry Authors: S Rodríguez-Acebes, P de la Cueva, C Fernández-Hernando, A J. Ferruelo, M A. Lasunción, R B. Rawson, J Martínez-Botas, D Gómez-Coronado Tags: BJ Cell Source Type: journals

Competition between NarL-dependent activation and Fis-dependent repression controls expression from the Escherichia coli yeaR and ogt promotersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Escherichia coli NarL protein is a global gene regulatory factor that activates transcription at many target promoters in response to nitrate and nitrite ions. Although most NarL-dependent promoters are also co-dependent on a second transcription factor, FNR, two targets, the yeaR and ogt promoters are activated by NarL alone with no involvement of FNR. Biochemical and genetic studies presented here show that activation of the yeaR promoter is dependent on the binding of NarL to a single target centred at position 43.5, whilst activation at the ogt promoter requires NarL binding to tandem DNA targets centred at positio...
Source: BJ Gene - February 26, 2009 Category: Biochemistry Authors: D J P Squire, M Xu, J A Cole, S J W Busby, D F Browning Tags: BJ Gene Source Type: journals

Proper expression of helix-loop-helix protein Id2 is important to chondrogenic differentiation of ATDC5 cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The process of chondrogenesis can be mimicked in vitro by insulin treatment of mouse ATDC5 chondroprogenitor cells. To identify novel factors that are involved in the control of chondrogenesis, we carried out a large-scale screening through retroviral insertion mutagenesis and isolated a fast-growing ATDC5 clone incapable of chondrogenic differentiation. Inverse-PCR analysis of this clone revealed that the retroviral DNA was inserted into the promoter region of mouse Id2 gene. This retroviral insertion increased Id2 protein level to twice as much as that in normal ATDC5 cells. To investigate whether an elevated level of Id...
Source: BJ Gene - January 28, 2009 Category: Biochemistry Authors: L Yang, X Ma, A Lyone, J Zou, M L Blackburn, J Pan, D Yang, H Matsushita, B Mei, A Zielinska-Kwiatkowska, H A. Chansky Tags: BJ Gene Source Type: journals

Resistance of Helicoverpa armigera to CRY1Ac toxin from Bacillus thuringiensis is due to improper processing of the protoxinEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The bacterium Bacillus thuringiensis produces insecticidal crystal proteins (ICP) that are deposited in their spore mother cells (SMC). When susceptible lepidopteran larvae ingest these SMC, the ICP get solubilised in the alkaline gut environment. Of about 140 insecticidal proteins described thus far, insecticidal protein Cry1Ac has been applied extensively as the main ingredient of spray formulation as well as the principal ICP introduced into crops as transgene for agricultural crop protection. The 135 kDa Cry1Ac protein upon ingestion by the insect is processed successively at the N and C- termini by the insect midgut p...
Source: BJ Gene - January 16, 2009 Category: Biochemistry Authors: R Rajagopal, N Arora, S Sivakumar, R N.G.V., N S.A., R K. Bhatnagar Tags: BJ Gene Source Type: journals

hCASK regulates the expression of p21 via E2A transcription factorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study revealed that hCASK mediates the protein and mRNA level of p21wafi/cip1 (p21), and activates the expression of p21 in a time-dependent manner. Two E-boxes in the proximal region at the transcription start site (TSS) play key roles in regulating hCASK-mediated p21 expression. We suggest that E2A (E12 and E47), a representative of the E proteins that binds the E-box elements, is an accomplice in the mediation of p21 expression by hCASK. The data suggest that hCASK regulation of cell growth might be involved in p21expression, while the bHLH transcription factor E2A probably participates in hCASK mediation of p21exp...
Source: BJ Gene - January 6, 2009 Category: Biochemistry Authors: R Sun, Y Su, X Zhao, J Qi, X Luo, Z Yang, Y Yao, X Luo, Z Xia Tags: BJ Signal Source Type: journals

Characterization of key residues and membrane association domains in RDH10Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
RDH10 was originally identified from the retinal pigment epithelium (RPE) and retinal Müller cells. It has retinoid oxidoreductase activity and is thought to play a role in the retinoid visual cycle. A recent study showed that RDH10 is essential for generating retinoic acid at early embryonic stages. The present study demonstrated that wild-type (wt) RDH10 catalyzed both oxidation of all-trans retinol and reduction of all-trans retinal in a cofactor-dependent manner in vitro. In cultured cells, however, oxidation is the favored reaction catalyzed by RDH10. Substitution of any of the predicted key residues in the cat...
Source: BJ Gene - December 22, 2008 Category: Biochemistry Authors: Y Takahashi, G Moiseyev, K Farjo, J Ma Tags: BJ Structure Source Type: journals

Physarum nitric oxide synthases: Genomic structures and enzymology of recombinant proteinsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Physarum polycephalum expresses two closely related, calcium-independent nitric oxide synthases. In previous work, we showed that both nitric oxide synthases are induced during starvation and apparently play a functional role for sporulation. Here, we characterized the genomic structures of both Physarum nitric oxide synthases, expressed both enzymes recombinantly in bacteria, and characterized their biochemical properties. Whereas the overall genomic organization of Physarum nitric oxide synthase genes is comparable to various animal nitric oxide synthases, none of the exon-intron boundaries are conserved. Recombinant exp...
Source: BJ Gene - December 1, 2008 Category: Biochemistry Authors: S Messner, S Leitner, C Bommassar, G Golderer, P Gröbner, E R Werner, G Werner-Felmayer Tags: BJ Gene Source Type: journals

The Drosophila nuclear factor DREF positively regulates the expression of the mitochondrial transcription termination factor DmTTFEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, by in silico analysis, we have identified DNA Replication-related Elements (DRE) in the promoter region of a gene participating in mtDNA transcription, the Drosophila mitochondrial Transcription Termination Factor (DmTTF). Transient transfection assays in Drosophila S2 cells, with mutated versions of DmTTF promoter region, showed that DRE elements control DmTTF transcription; moreover, gel-shift and ChIP assays demonstrated that the analysed DRE sites interact with DREF either in vitro and in vivo. Accordingly, DREF knockdown in S2 cells by RNA interference induced a considerable decrease in DmTTF mRNA level...
Source: BJ Gene - November 25, 2008 Category: Biochemistry Authors: M Á Fernández-Moreno, F Bruni, C Adán, R Hernández Sierra, P Loguercio Polosa, P Cantatore, R Garesse, M Roberti Tags: BJ Gene Source Type: journals

Active site substitutions delineate distinct classes of eubacterial flap endonucleaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present evidence of paralogous FEN-encoding genes present in many eubacteria. Two distinct classes of these independent FEN-encoding genes exist with four groups of eubacteria being identified based on the number and type of FEN gene encoded. The respective proteins possess distinct motifs hallmarking their differentiation. Crucially, based on primary sequence and predicted secondary structural motifs, we reveal key differences at their active site. These data are supported by biochemical characterization of two family members - exonuclease IX (ExoIX) from Escherichia coli and Staphylococcus aureus flap endonuclease (Sa...
Source: BJ Gene - November 11, 2008 Category: Biochemistry Authors: L M Allen, M R G Hodskinson, J R Sayers Tags: BJ Structure Source Type: journals

The selenocysteine tRNA STAF-binding region is essential for adequate selenocysteine tRNA status, selenoprotein expression and early age survival of miceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
STAF is a transcription activating factor for a number of RNA Pol III- and RNA Pol II-dependent genes including the selenocysteine (Sec) tRNA gene, which in turn controls the expression of all selenoproteins. Here, the role of STAF in regulating expression of Sec tRNA and selenoproteins was examined. We generated transgenic mice expressing the Trsp transgene lacking the STAF binding site and made these mice dependent on the transgene for survival by removing the wild type Sec tRNA gene. The level of Sec tRNA was unaffected or slightly elevated in heart and testis, but reduced ~60% in liver and kidney, ~70% in lung and sple...
Source: BJ Gene - October 30, 2008 Category: Biochemistry Authors: B A Carlson, U Schweizer, C Perella, R K Shrimali, L Feigenbaum, L Shen, S Speransky, T Floss, S Jeong, J Watts, V Hoffmann, G F Combs, Jr., V N Gladyshev, D L Hatfield Tags: BJ Gene Source Type: journals

Peptide mimics of a conserved H5N1 avian influenza virus neutralization siteEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion. Findings inferred that 8H5 recognizes discontinuous sites presented by secondary and possibly higher structural orders of the peptides in spatially favorable positions for binding with the antibody, and that the peptides partially mimic the native 8H5 epitopes on the H5N1 virus. (Source: BJ Gene)
Source: BJ Gene - October 30, 2008 Category: Biochemistry Authors: W Luo, Y Chen, M Wang, Y Chen, Z Zheng, H Song, H chen, Y Guan, M Ng, J Zhang, N Xia Tags: BJ Disease Source Type: journals

Insulin and epidermal growth factor suppress basal glucose-6-phosphatase catalytic subunit gene transcription through overlapping but distinct mechanismsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The glucose-6-phosphatase catalytic subunit (G6Pase) catalyses the final step in the gluconeogenic and glycogenolytic pathways, the hydrolysis of glucose-6-phosphate to glucose. We show here that, in HepG2 hepatoma cells, epidermal growth factor (EGF) inhibits basal mouse G6Pase fusion gene transcription. Several studies have shown that insulin represses basal mouse G6Pase fusion gene transcription through FOXO1 but Stoffel and colleagues (Proc. Natl. Acad. Sci. 100:11624, 2003) have recently suggested that insulin can also regulate gene transcription through FOXA2. A combined glucocorticoid receptor (GR)-FOXA2 binding sit...
Source: BJ Gene - October 10, 2008 Category: Biochemistry Authors: H Onuma, J K Oeser, B A Nelson, Y Wang, B P Flemming, L A Scheving, W E Russell, R M O'Brien Tags: BJ Gene Source Type: journals

Transcriptional induction of the human asparagine synthetase gene during the unfolded protein response does not require the ATF6 and IRE1/XBP1 arms of the pathwayEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Unfolded Protein Response (UPR) pathway is comprised of three signaling cascades mediated by the ER stress sensor proteins PERK, IRE1, and ATF6. The present study shows that asparagine synthetase (ASNS) transcription activity was up-regulated in HepG2 cells treated with the UPR activators thapsigargin and tunicamycin. Chromatin immunoprecipitation (ChIP) analysis demonstrated that during ER stress ATF4, ATF3, and C/EBPβ bind to the ASNS proximal promoter region that includes the genomic sequences Nutrient Sensing Response Elements-1,2 (NSRE-1, NSRE-2), previously implicated by mutagenesis in UPR activation. Cons...
Source: BJ Gene - October 8, 2008 Category: Biochemistry Authors: A Gjymishka, N Su, M S Kilberg Tags: BJ Gene Source Type: journals

The transporter CefM involved in translocation of biosynthetic intermediates is essential for cephalosporin productionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The cluster of early cephalosporin biosynthesis genes (pcbAB, pcbC, cefD1, cefD2 and cefT of Acremonium chrysogenum) contains all genes required for the biosynthesis of the cephalosporin biosynthetic pathway intermediate penicillin N. Downstream of the cefD1 gene there is an unassigned open reading frame named cefM encoding a protein of the MFS family with 12 transmembrane spanning domains, different from the previously reported cefT. Targeted inactivation of cefM by gene replacement showed that it is essential for cephalosporin biosynthesis. The disrupted mutant accumulates a significant amount of penicillin N, is unable ...
Source: BJ Gene - October 8, 2008 Category: Biochemistry Authors: F Teijeira, R V. Ullán, S M. Guerra, C García-Estrada, I Vaca, J F. Martín Tags: BJ Gene Source Type: journals

High incidence of DNA mutations and gene amplifications of the ALK gene in advanced sporadic neuroblastoma tumoursEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Anaplastic lymphoma kinase (ALK) is oncogenic in several tumours and recently identified as a predisposition gene for familial neuroblastoma (NB) harbouring mutations in the tyrosine kinase domain (TKD). We have analysed a large set of sporadic human NB primary tumours of all clinical stages for chromosomal re-arrangements using array-CGH (n=108) and mutations of the ALK gene (n=90), and expression of ALK and related genes (n=19). ALK amplification or in-gene re-arrangements were found in 5% of NB tumours and mutations in 11% including two novel not previously published mutations in the TKD; c.3733T>A and c.3735C>A. DNA mu...
Source: BJ Gene - October 7, 2008 Category: Biochemistry Authors: H Carén, F Abel, P Kogner, T Martinsson Tags: BJ Disease Source Type: journals

P/CAF modulates the activity of the transcription factor p48/PTF1a involved in pancreatic acinar differentiationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
p48, also called Ptf1a, is a tissue-restricted basic helix-loop-helix transcription factor critical for pancreatic commitment during development and for the activation/maintenance of the acinar differentiation program in exocrine pancreas. High-level expression of exocrine digestive enzymes, a hallmark of mature acinar cells, depends largely on the trimeric complex PTF1 (pancreas transcription factor 1), formed by p48, RBP-L and a class A bHLH protein. In addition, p48 induces cell cycle exit by controlling G1-S progression. However, the mechanisms that mediate the PTF1-dependent gene activation are poorly understood. Here...
Source: BJ Gene - October 6, 2008 Category: Biochemistry Authors: A Rodolosse, M Campos, I Rooman, M Lichtenstein, F X Real Tags: BJ Disease Source Type: journals

Two biochemically distinct and tissue-specific twinfilin isoforms are generated from mouse twinfilin-2 gene by alternative promoter usageEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Twinfilin is an evolutionarily conserved regulator of actin dynamics composed of two actin-depolymerizing factor homology (ADF-H) domains. Twinfilin binds actin monomers and heterodimeric capping protein with high affinity. Previous studies demonstrated that mammals express two twinfilin isoforms, twinfilin-1 and twinfilin-2, of which at least twinfilin-1 also regulates cytoskeletal dynamics by capping actin filament barbed ends. Here, we show that alternative promoter usage of the mouse twinfilin-2 gene generates two isoforms, which differ from each other only at their very N-terminal region. Of these isoforms, twinfilin-...
Source: BJ Gene - October 6, 2008 Category: Biochemistry Authors: E Merja Nevalainen, A Skwarek-Maruszewska, A Braun, M Moser, P Lappalainen Tags: BJ Cell Source Type: journals

BCL11B enhances TCR/CD28-triggered NF-kB activation through upregulation of Cot kinase gene expression in T lymphocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
BCL11B is a transcriptional regulator with important role in T cell development and leukemogenesis. Recently we demonstrated that BCL11B controls expression from IL-2 promoter through direct binding to the US1 site. Here we provide evidence that BCL11B also participates in the activation of IL-2 gene expression by enhancing NF-kB activity in the context of TCR/CD28–triggered T cell activation. Enhanced NF-kB activation is not a consequence of BCL11B binding to the NF-kB response elements or association with the NF-kB-DNA complexes, but rather the result of higher translocation of NF-kB to the nucleus caused by enhan...
Source: BJ Gene - October 3, 2008 Category: Biochemistry Authors: V B Cismasiu, J Duque, E Paskaleva, D Califano, S Ghanta, H A Young, D Avram Tags: BJ Cell Source Type: journals

A chimeric glutamyl: glutaminyl-tRNA synthetase: implications for evolutionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Aminoacyl-tRNA synthetases (aaRS) are multi-domain proteins that have evolved by domain acquisition. The anti-codon binding domain was added to the more ancient catalytic domain during aaRS evolution. Unlike in eukaryotes, the anti-codon binding domains of GluRS and GlnRS in bacteria are structurally distinct. This originates from the unique evolutionary history of GlnRSs. Starting from the catalytic domain, eukaryotic GluRS evolved by acquiring the archaea/eukaryote-specific anti-codon binding domain after branching away from the eubacteria family. Subsequently, eukaryotic GlnRS evolved from GluRS by gene duplication and ...
Source: BJ Gene - September 26, 2008 Category: Biochemistry Authors: R Saha, S Dasgupta, G Basu, S Roy Tags: BJ Structure Source Type: journals

A cysteine-rich metal-binding domain from rubella virus nonstructural protein is essential for viral protease activity and virus replicationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we carried out metal-binding and conformational studies on a purified cysteine-rich minidomain of the RUBV NS protease containing the putative Zn binding ligands. This minidomain bound to zinc ions with a stoichiometry of ~0.7 and an apparent dissociation constant of < 500 nM. Fluorescence quenching and ANS fluorescence methods revealed that zinc binding resulted in conformational changes characterized by shielding of hydrophobic regions from the solvent. Mutational analyses using the minidomain identified residues C1175, C1178, C1225 and C1227 were required for the binding of zinc ions. Corresponding mutati...
Source: BJ Gene - September 17, 2008 Category: Biochemistry Authors: Y Zhou, W Tzeng, Y Ye, Y Huang, Y Chen, T K. Frey, J J. Yang Tags: BJ Structure Source Type: journals

Hepatitis B virus X protein induces lipogenic transcription factor SREBP1 and fatty acid synthase through the activation of nuclear receptor LXR alphaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we demonstrate that the HBx protein interacts with LXRα and enhances the binding of LXRα to the LXR-response element (LXRE), thereby resulting in the upregulation of SREBP1 and fatty acid synthase (FAS) in the presence or absence of the LXR agonist T0901317 in the hepatic cells and HBx-transgenic mice. Furthermore, HBx also augments the ability to recruit the activating signal cointegrator 2 (ASC2), a transcriptional coactivator that controls liver lipid metabolic pathways, to the LXRE with LXRα. These studies place LXRα in a key position within the HBx-induced lipogenic pathways,...
Source: BJ Gene - September 10, 2008 Category: Biochemistry Authors: K Kim, K Kim, H Kim, J Cheong Tags: BJ Gene Source Type: journals

Depletion of nucleophosmin leads to distortion of nucleolar and nuclear structures in HeLa cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we show dynamic localization of NPM throughout the cell cycle of HeLa cells. Using a combination of RNA interference (RNAi) and 3-D microscopy here we show that NPM is localized at the chromosome periphery during mitosis. We also demonstrate that depletion of NPM causes distortion of nucleolar structure as expected and leads to unexpected dramatic changes in nuclear morphology with multiple micronuclei formation. The defect in nuclear shape of NPM depleted cells, which is clearly observed by live cell imaging, is due to the distortion of cytoskeletal (α-tubulin and β-actin) structure resulting ...
Source: BJ Gene - August 27, 2008 Category: Biochemistry Authors: M Abdullahel Amin, S Matsunaga, S Uchiyama, K Fukui Tags: BJ Cell Source Type: journals

Cytoplasmic polyadenylation element binding protein (CPEB)1 and 2 bind to the HIF-1{alpha} mRNA 3{'}UTR and modulate HIF-1 {alpha} protein expressionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The heterodimeric hypoxia-inducible factor (HIF)-1 is a transcriptional master regulator of several genes involved in mammalian oxygen homeostasis. Besides a well described regulation of the HIFα-subunit via hydroxylation-mediated protein stability in hypoxia, there are several indications for an additional translational control of the HIF-1α mRNA especially after growth factor stimulation. We identified an interaction of the cytoplasmic polyadenylation element binding protein (CPEB) 1 and 2 with the 3'-UTR of the HIF-1α mRNA. Overexpression of CPEB1 and 2 affected HIF-1α protein levels mediated...
Source: BJ Gene - August 27, 2008 Category: Biochemistry Authors: S Hägele, U Kühn, M Böning, D Magdalena Katschinski Tags: BJ Signal Source Type: journals