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Mammalian Orthologs (mammalian + ortholog)
Selected Abstracts,4 phosphoprotein interacts with EDD E3 ubiquitin ligase and poly(A)-binding proteinJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2010William J. McDonald Abstract Mammalian ,4 phosphoprotein, the homolog of yeast Tap42, is a component of the mammalian target-of-rapamycin (mTOR) pathway that regulates ribogenesis, the initiation of translation, and cell-cycle progression. ,4 is known to interact with the catalytic subunit of protein phosphatase 2A (PP2Ac) and to regulate PP2A activity. Using ,4 as bait in yeast two-hybrid screening of a human K562 erythroleukemia cDNA library, EDD (E3 isolated by differential display) E3 ubiquitin ligase was identified as a new protein partner of ,4. EDD is the mammalian ortholog of Drosophila hyperplastic discs gene (hyd) that controls cell proliferation during development. The EDD protein contains a PABC domain that is present in poly(A)-binding protein (PABP), suggesting that PABP may also interact with ,4. PABP recruits translation factors to the poly(A)-tails of mRNAs. In the present study, immunoprecipitation/immunoblotting (IP/IB) analyses showed a physical interaction between ,4 and EDD in rat Nb2 T-lymphoma and human MCF-7 breast cancer cell lines. ,4 also interacted with PABP in Nb2, MCF-7 and the human Jurkat T-leukemic and K562 myeloma cell lines. COS-1 cells, transfected with Flag-tagged-pSG5-EDD, gave a (Flag)-EDD,,4 immunocomplex. Furthermore, deletion mutants of ,4 were constructed to determine the binding site for EDD. IP/IB analysis showed that EDD bound to the C-terminal region of ,4, independent of the ,4-PP2Ac binding site. Therefore, in addition to PP2Ac, ,4 interacts with EDD and PABP, suggesting its involvement in multiple steps in the mTOR pathway that leads to translation initiation and cell-cycle progression. J. Cell. Biochem. 110: 1123,1129, 2010. Published 2010 Wiley-Liss, Inc. [source] Significance of error-avoiding mechanisms for oxidative DNA damage in carcinogenesisCANCER SCIENCE, Issue 4 2007Teruhisa Tsuzuki Reactive oxygen species (ROS) are produced through normal cellular metabolism, and their formation is further enhanced by exposure to ionizing radiation and various chemicals. ROS attack DNA, and the resulting oxidative DNA damage is considered to contribute to aging, carcinogenesis and neurodegeneration. Among various types of oxidative DNA damage, 8-oxo-7,8-dihydroguanine (8-oxoguanine or 8-oxoG) is the most abundant, and plays significant roles in mutagenesis because of its ability to pair with adenine as well as cytosine. Enzymatic activities that may be responsible for preventing 8-oxoG-evoked mutations were identified in mammalian cells. We have focused on the following three enzymes: MTH1, OGG1 and MUTYH. MTH1 is a mammalian ortholog of Escherichia coli MutT, which hydrolyzes 8-oxo-dGTP to its monophosphate form in nucleotide pools, thereby preventing incorporation of the mutagenic substrate into DNA. OGG1, a functional counterpart of E. coli MutM, has an 8-oxoG DNA glycosylase activity. MUTYH, a mammalian ortholog of E. coli MutY, excises an adenine paired with 8-oxoG. These three enzymes are thought to prevent mutagenesis caused by 8-oxoG in mammals. To analyze the functions of mammalian MTH1 (Mth1), OGG1 (Ogg1) and MUTYH (Mutyh) in vivo, we established mutant mice for these three enzymes by targeted mutagenesis, and investigated spontaneous tumorigenesis as well as mutagenesis. Here we discuss our recent investigation of mutagenesis and carcinogenesis in these mutant mice. (Cancer Sci 2007; 98: 465,470) [source] bmp2b and bmp4 are dispensable for zebrafish tooth developmentDEVELOPMENTAL DYNAMICS, Issue 10 2010Sarah B. Wise Abstract Bone morphogenetic protein (Bmp) signaling has been shown to play important roles in tooth development at virtually all stages from initiation to hard tissue formation. The specific ligands involved in these processes have not been directly tested by loss-of-function experiments, however. We used morpholino antisense oligonucleotides and mutant analysis in the zebrafish to reduce or eliminate the function of bmp2b and bmp4, two ligands known to be expressed in zebrafish teeth and whose mammalian orthologs are thought to play important roles in tooth development. Surprisingly, we found that elimination of function of these two genes singly and in combination did not prevent the formation of mature, attached teeth. The mostly likely explanation for this result is functional redundancy with other Bmp ligands, which may differ between the zebrafish and the mouse. Developmental Dynamics 239:2534,2546, 2010. © 2010 Wiley-Liss, Inc. [source] Molecular cloning of the Matrix Gla Protein gene from Xenopus laevisFEBS JOURNAL, Issue 7 2002Functional analysis of the promoter identifies a calcium sensitive region required for basal activity To analyze the regulation of Matrix Gla Protein (MGP) gene expression in Xenopus laevis, we cloned the xMGP gene and its 5, region, determined their molecular organization, and characterized the transcriptional properties of the core promoter. The Xenopus MGP (xMGP) gene is organized into five exons, one more as its mammalian counterparts. The first two exons in the Xenopus gene encode the DNA sequence that corresponds to the first exon in mammals whereas the last three exons show homologous organization in the Xenopus MGP gene and in the mammalian orthologs. We characterized the transcriptional regulation of the xMGP gene in transient transfections using Xenopus A6 cells. In our assay system the identified promoter was shown to be transcriptionally active, resulting in a 12-fold induction of reporter gene expression. Deletional analysis of the 5, end of the xMGP promoter revealed a minimal activating element in the sequence from ,70 to ,36 bp. Synthetic reporter constructs containing three copies of the defined regulatory element delivered 400-fold superactivation, demonstrating its potential for the recruitment of transcriptional activators. In gel mobility shift assays we demonstrate binding of X. laevis nuclear factors to an extended regulatory element from ,180 to ,36, the specificity of the interaction was proven in competition experiments using different fragments of the xMGP promoter. By this approach the major site of factor binding was demonstrated to be included in the minimal activating promoter fragment from ,70 to ,36 bp. In addition, in transient transfection experiments we could show that this element mediates calcium dependent transcription and increasing concentrations of extracellular calcium lead to a significant dose dependent activation of reporter gene expression. [source] Basic characterization of 90 kDa heat shock protein genes HSP90AA1, HSP90AB1, HSP90B1 and TRAP1 expressed in Japanese quail (Coturnix japonica)ANIMAL SCIENCE JOURNAL, Issue 4 2010Kohji NAGAHORI ABSTRACT In the current study, we describe four novel members of the 90 kDa heat shock protein (HSP90) family expressed in Japanese quail, Coturnix japonica. The coding regions of the genes, CjHSP90AA1, CjHSP90AB1, CjHSP90B1 and CjTRAP1, exhibited more than 94% similarity to their related genes in chicken. The putative proteins encoded by these quail genes contained motifs considered essential for HSP90 gene function. In addition, the predicted proteins were more similar to HSP90AA1, HSP90AB1, HSP90B1 and TRAP1 proteins expressed in vertebrates than they were to other members of the HSP90 family. Exon numbers of CjHSP90AA1 (11), CjHSP90AB1 (12) or CjTRAP1 (18) are the same as the chicken and mammalian orthologs. Furthermore, gene order in the regions surrounding CjHSP90AB1 and CjTRAP1 has been preserved, providing evidence that the genomic regions were orthologous to HSP90-containing regions in the chicken genome. The promoter regions of the genes also contained conserved motifs identified in related genes of chicken. However, the nucleotide sequences of the 5,-flanking region of these genes were highly polymorphic. We also found that CjHSP90AA1 exhibited a robust response to heat shock treatment. Taken together, the data suggest that CjHSP90AA1, CjHSP90AB1, CjHSP90B1 and CjTRAP1 encode orthologs of HSP90AA1, HSP90AB1, HSP90B1 and TRAP1, respectively. [source] | ||||||||||