Genes to Cells
1365-2443
1356-9597
Anh Quốc
Cơ quản chủ quản: WILEY , Wiley-Blackwell Publishing Ltd
Lĩnh vực:
Medicine (miscellaneous)Cell BiologyGenetics
Phân tích ảnh hưởng
Thông tin về tạp chí
Genes to Cells provides an international forum for the publication of papers describing important aspects of molecular and cellular biology. The journal aims to present papers that provide conceptual advance in the relevant field. Particular emphasis will be placed on work aimed at understanding the basic mechanisms underlying biological events.
Các bài báo tiêu biểu
Molecular mechanisms of the Keap1-Nrf2 pathway in stress response and cancer evolution
Tập 16 Số 2 - Trang 123-140 - 2011
<scp>TET</scp>3–<scp>OGT</scp> interaction increases the stability and the presence of <scp>OGT</scp> in chromatin Gene expression is controlled by alterations in the epigenome, including DNA methylation and histone modification. Recently, it was reported that 5‐methylcytosine (5mC) is converted to 5‐hydroxymethylcytosine (5hmC) by proteins in the ten‐eleven translocation (TET ) family. This conversion is believed to be part of the mechanism by which methylated DNA is demethylated. Moreover, histones undergo modifications such as phosphorylation and acetylation. In addition, modification with O ‐linked‐N ‐acetylglucosamine (O ‐GlcNA c) by O ‐GlcNA c transferase (OGT ) was recently identified as a novel histone modification. Herein, we focused on TET 3, the regulation of which is still unclear. We attempted to elucidate the mechanism of its regulation by biochemical approaches. First, we conducted mass spectrometric analysis in combination with affinity purification of FLAG –TET 3, which identified OGT as an important partner of TET 3. Co‐immunoprecipitation assays using a series of deletion mutants showed that the C‐terminal H domain of TET 3 was required for its interaction with OGT . Furthermore, we showed that TET 3 is GlcNA cylated by OGT , although the GlcNA cylation did not affect the global hydroxylation of methylcytosine by TET 3. Moreover, we showed that TET 3 enhanced its localization to chromatin through the stabilization of OGT protein. Taken together, we showed a novel function of TET 3 that likely supports the function of OGT .
Tập 19 Số 1 - Trang 52-65 - 2014
Identification and characterization of tRNA (Gm18) methyltransferase from <i>Thermus thermophilus</i> HB8: domain structure and conserved amino acid sequence motifs Abstract Background: Transfer RNAs from an extreme thermophile, Thermus thermophilus , commonly possess 2′‐O‐methylguanosine at position 18 (Gm18) in the D‐loop. This modification is post‐transcriptionally introduced by tRNA (Gm18) methyltransferase. Results: Partial amino acid sequence data were obtained from purified T. thermophilus tRNA (Gm18) methyltransferase by peptide sequencing and mass spectrometry. The sequence data were used to screen the T. thermophilus genome database currently in progress, resulting in the identification of the corresponding gene. Purified recombinant enzyme showed a strict specificity for methylation at the 2′‐OH of G18 in tRNA. Sequence alignment with other known or putative methyltransferases elucidates that tRNA (Gm18) methyltransferases have specific conserved region as well as three consensus motifs found in RNA ribose 2′‐O‐methyltransferases. The enzyme truncated at its N and C termini by limited tryptic digestion still retained binding activity for S‐adenosyl‐l ‐homocysteine, but lost the catalytic activity.Conclusion: This is the first report describing the identification of a methyltransferase gene of the trmH family through the analysis of a purified protein. Further, our results indicate that a restricted region(s) in the terminal amino acid residues of T. thermophilus tRNA (Gm18) methyltransferase are responsible for tRNA recognition and a main part of the enzyme is allocated for a catalytic core.
Tập 7 Số 3 - Trang 259-272 - 2002
Interaction of Rho‐kinase with myosin II at stress fibres Rho‐kinase and myosin phosphatase cooperatively regulate the phosphorylation level of myosin light chain and are involved in the formation of stress fibres and smooth muscle contraction. Rho‐kinase has been known to be localized at stress fibres, but little is known about the mechanism of its localization. Here we identified non‐muscle myosin heavy chain IIA and IIB as the pleckstrin homology domain‐interacting molecules by affinity column chromatography. The pleckstrin homology domain of Rho‐kinase binds to myosin II directly in in vitro cosedimentation assay. The C‐terminal region of the pleckstrin homology domain was important for this interaction, and the point mutations in the pleckstrin homology domain mutant (W1170A, W1340L) resulted in a decrease in the binding. We also found that the pleckstrin homology domain, but not the pleckstrin homology domain mutant (W1170A, W1340L), was localized at stress fibres in fibroblasts. These results indicate that Rho‐kinase is localized at stress fibres through binding of the pleckstrin homology domain to myosin II.
Tập 9 Số 7 - Trang 653-660 - 2004
Maintenance of self‐renewal ability of mouse embryonic stem cells in the absence of DNA methyltransferases Dnmt1, Dnmt3a and Dnmt3b DNA methyltransferases Dnmt1, Dnmt3a and Dnmt3b cooperatively regulate cytosine methylation in CpG dinucleotides in mammalian genomes, providing an epigenetic basis for gene silencing and maintenance of genome integrity. Proper CpG methylation is required for the normal growth of various somatic cell types, indicating its essential role in the basic cellular function of mammalian cells. Previous studies using Dnmt1 −/– or Dnmt3a −/– Dnmt3b −/– ES cells, however, have shown that undifferentiated embryonic stem (ES) cells can tolerate hypomethylation for their proliferation. In an attempt to investigate the effects of the complete loss of CpG DNA methyltransferase function, we established mouse ES cells lacking all three of these enzymes by gene targeting. Despite the absence of CpG methylation, as demonstrated by genome‐wide methylation analysis, these triple knockout (TKO) ES cells grew robustly and maintained their undifferentiated characteristics. TKO ES cells retained pericentromeric heterochromatin domains marked with methylation at Lys9 of histone H3 and heterochromatin protein‐1, and maintained their normal chromosome numbers. Our results indicate that ES cells can maintain stem cell properties and chromosomal stability in the absence of CpG methylation and CpG DNA methyltransferases.
Tập 11 Số 7 - Trang 805-814 - 2006
Roles of lipid rafts in integrin‐dependent adhesion and gp130 signalling pathway in mouse embryonic neural precursor cells Neuronal and glial cells organizing the central nervous system are generated from common neural precursor cells present in the neuroepithelium during development. We tried to clarify functions of a cell surface microdomain, lipid raft, in neuroepithelial cells (NECs). NECs are suggested to adhere to fibronectin substratum dependently on integrin molecules. We found that β1 integrin, a component of fibronectin receptors, was distributed in lipid rafts. Methyl‐β‐cyclodextrin (MBCD), an inhibitor of lipid raft formation, inhibited the integrin‐fibronectin interaction‐dependent adhesion of NECs. However, inhibition of synthesis of glycosphingolipids (GSL), components of lipid rafts, did not affect NEC adhesion. Leukaemia inhibitory factor (LIF), an interleukin 6 type cytokine, induces astrocyte differentiation of NECs via activation of a transcription factor STAT3. We detected gp130, JAK1 and Ras but not STAT3 and ERK2 molecules in lipid rafts of NECs. Disruption of lipid rafts by MBCD inhibited LIF‐induced ERK activation but not STAT3 activation. It is thus suggested that LIF‐downstream molecules have differential lipid raft‐dependency in terms of activation upon LIF‐stimulation. In this study, we found functions of lipid rafts in cell adhesion and signal transduction in NECs. This is the first report that characterized functions of lipid rafts in embryonic neural precursor cells.
Tập 9 Số 9 - Trang 801-809 - 2004
High copy number suppression of the meiotic arrest caused by a <i>dmc1</i> mutation: <i>REC114</i> imposes an early recombination block and <i>RAD54 </i>promotes a <i>DMC1</i>‐independent DSB repair pathway Background DMC1 , the meiosis‐specific eukaryotic homologue of bacterial recA , is required for completion of meiotic recombination and cell cycle progression past prophase. In a dmc1 mutant, double strand break recombination intermediates accumulate and cells arrest in prophase. We isolated genes which, when present at high copy numbers, suppress the meiotic arrest phenotype conferred by dmc1 mutations. Results Among the genes isolated were two which suppress arrest by altering the recombination process. REC114 suppresses formation of double strand break (DSB) recombination intermediates. The low viability of spores produced by dmc1 mutants carrying high copy numbers of REC114 is rescued when reductional segregation is bypassed by mutation of spo13 . High copy numbers of RAD54 suppress dmc1 arrest, promote DSB repair, and allow formation of viable spores following reductional segregation. Analysis of the combined effects of a null mutation in RED1 , a gene required for meiotic chromosome structure, with null mutations in RAD54 and DMC1 shows that RAD54 , while not normally important for repair of DSBs during meiosis, is required for efficient repair of breaks by the intersister recombination pathway that operates in red1 dmc1 double mutants. Conclusions Over‐expression of REC114 suppresses meiotic arrest by preventing formation of DSBs. High copy numbers of RAD54 activate a DMC1 ‐independent mechanism that promotes repair of DSBs by homology‐mediated recombination. The ability of RAD54 to promote DMC1 ‐independent recombination is proposed to involve suppression of a constraint that normally promotes recombination between homologous chromatids rather than sisters.
Tập 4 Số 8 - Trang 425-444 - 1999
Attenuation of cell motility observed with high doses of sphingosine 1‐phosphate or phosphorylated FTY720 involves RGS2 through its interactions with the receptor S1P Sphingosine 1‐phosphate (S1P) stimulation enhances cell motility via the G‐protein coupled S1P receptor S1P1. This ligand‐induced, receptor‐mediated cell motility follows a typical bell‐shaped dose–response curve, that is, stimulation with low concentrations of S1P enhances cell motility, whereas excess ligand stimulation does not enhance it. So far, the attenuation of the response at higher ligand concentrations has not been explained. We report here that S1P1 interacts with the regulator of G protein signaling (RGS)‐2 protein, which is a GTPase‐activating protein (GAP) for heterotrimeric G proteins, in a concentration dependent manner. The RGS2–S1P1 complex dissociated at higher ligand concentrations, yet it was unaffected at low concentrations, suggesting that the dissociated RGS2 is involved in the concurrent decrease of cell motility. In RGS2 knockdown cells, the decrease of cell motility induced by high ligand concentrations was rescued. S1P1 internalization was not implicated in the attenuation of the response. Similar results were observed upon stimulation with the phosphorylated form of FTY720 (FTYP), which is an S1P1 agonist. In conclusion, the suppressed response in cell motility induced by excess S1P or FTYP via S1P1 is regulated by RGS2 functioning through a mechanism that is independent of S1P1 internalization.
Tập 13 Số 7 - Trang 747-757 - 2008
Targeted disruption of ATF4 discloses its essential role in the formation of eye lens fibres Background : Activating transcription factor‐4 (ATF4)—also termed CREB2, C/ATF, and TAXREB67—is a basic‐leucine zipper (bZip) transcription factor that belongs to the ATF/CREB family. In addition to its own family members, ATF4 can also form heterodimers with other related but distinct bZIP proteins such as the C/EBP, AP‐1 and Maf families, which may give rise to a variety of combinatorial diversity in gene regulation. In order to assess the in vivo essential role of ATF4, we have generated mice lacking ATF4 by gene targeting. Results : ATF4‐deficient mice exhibited severe microphthalmia. Although ATF4‐deficient eyes revealed a normal gross lens structure up to embryonic day 14.5, later on the ATF4‐deficient lens, degenerated due to apoptosis without the formation of lens secondary fibre cells. Retinal development was normal in the mutant mice. The lens‐specific expression of ATF4 in the mutant mice led not only to the recovery of lens secondary fibres but also to the induction of hyperplasia of these fibres. Conclusion : These results demonstrated that ATF4 is essential for the later stages of lens fibre cell differentiation.
Tập 3 Số 12 - Trang 801-810 - 1998
Identification of mesenchymal stem cell (MSC)‐transcription factors by microarray and knockdown analyses, and signature molecule‐marked MSC in bone marrow by immunohistochemistry Althoughex vivo expanded mesenchymal stem cells (MSC) have been used in numerous studies, the molecular signature andin vivo distribution status of MSC remain unknown. To address this matter, we identified numerous human MSC‐characteristic genes—including nine transcription factor genes —using DNA microarray and real‐time RT‐PCR analyses: Most of the MSC‐characteristic genes were down‐regulated 24 h after incubation with osteogenesis‐, chondrogenesis‐ or adipogenesis‐induction medium, or 48–72 h after knockdown of the nine transcription factors. Furthermore, knockdowns of ETV1, ETV5, FOXP1, GATA6, HMGA2, SIM2 or SOX11 suppressed the self‐renewal capacity of MSC, whereas those of FOXP1, SOX11, ETV1, SIM2 or PRDM16 reduced the osteogenic‐ and/or adipogenic potential. In addition, immunohistochemistry using antibodies for the MSC characteristic molecules—including GATA6, TRPC4, FLG and TGM2—revealed that MSC‐like cells were present near the endosteum and in the interior of bone marrow of adult mice. These findings indicate that MSC synthesize a set of MSC markersin vitro andin vivo , and that MSC‐characteristic transcription factors are involved in MSC stemness regulation.
Tập 14 Số 3 - Trang 407-424 - 2009