The human C17orf25 gene (Accession No. AF177342) is one of thirteen genes cloned from a region displaying a high score of loss of heterozygosity within chromosome 17pl3.3 in human hepatocellular carcinoma in China[l]....The human C17orf25 gene (Accession No. AF177342) is one of thirteen genes cloned from a region displaying a high score of loss of heterozygosity within chromosome 17pl3.3 in human hepatocellular carcinoma in China[l]. To unveil the underlying mechanisms for the transcription regulation of this gene and understand its implication to the hepatocellular carcinogenesis, we looked into the relevant aspects by both bioinformatic and experimental executions. We found: 1, The abundant expression of the C17orf25 gene was evident in all the cell lines and tissue samples tested, showing little hepatoma-selectivity; 2, Its transcription starts at a single site, locating at -60 from the translation initiation codon; 3, A 58 bp fragment containing the transcription start, extending from -112 to -55, represents the minimal promoter; 4, The consensus sequence within this fragment recognized by SP1 contributes predominantly to the activity of the minimal promoter; 5, The bioinformatic analysis suggests that the C17orf25 gene may encode a protein in the family of the glyoxalase. Our data has provided some deep insight into both function and regulation of the C1 7orf25 gene in the context of the normal liver and hepatocellular carcinoma.展开更多
Background： The p21-activated kinase 1 （PAK1）is essential of microtubule assembly during oocyte meiotic maturation porcine oocytes. for mitosis and plays an important role in the regulatio in mice; however, little ...Background： The p21-activated kinase 1 （PAK1）is essential of microtubule assembly during oocyte meiotic maturation porcine oocytes. for mitosis and plays an important role in the regulatio in mice; however, little is known about its role in Result： Total p21-activated kinase 1 （PAK1） and phosphorylated PAK1 at Thr423 （PAK1^Thr423） were consistently expressed in porcine oocytes from the germinal vesicle （GV） to the second metaphase （MII） stages, but phosphorylation of histone H3 at Serr10 （H3^ser10） was only expressed after the GV stage. Immunofiuorescence analysis revealed that PAK1Thr423 and H3^ser10 colocalized on chromosomes after the GV stage. Blocking of endogenous PAK1^Thr423 by injecting a specific antibody decreased the phosphorylation level of H3^ser10; however, it had no impact on chromatin condensation, meiotic progression, cleavage rate of blastomeres or the rate of blastocyst formation. Conclusion： Phosphorylation of PAK1^Thr423 is a spontaneous activation process and the activated PAK1^Thr423 can promote the phosphorylation of H3^ser10; however, this pathway is not required for meiotic maturation of porcine oocytes or early embryonic development.展开更多
Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-reg...Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-regulated kinase(ERK)pathway is thought to increase cell proliferation and to protect cells from apoptosis.The aim of the study was to investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.Methods:Four human colon cancer cell lines,HCT1116 and Lovo(wildtype p53),DLD1 and SW1116(mutant p53),were used.Lovo stable transfectants with XAF1 sense and antisense were established.The effects of dominant-negative MEK1(DN-MEK1)and MEK-specific inhibitor U0126 on the ERK signaling pathway and expression of XAF1 and XIAP proteins were determined.The transcription activity of core XAF1 promoter was assessed by dual luciferase reporter assay.Cell proliferation was measured by MTT assay.Apoptosis was determined by Hoechst 33258 staining.Results:U0126 increased the expression of XAF1 in a time-and dose-dependent manner.A similar result was obtained in cells transfected with DN-MEK1 treatment.Conversely,the expression of XIAP was down-regulated.Activity of the putative promoter of the XAF1 gene was significantly increased by U0126 treatment and DN-MEK1 transient transfection.rhEGF-stimulated phosphorylation of ERK appeared to have little or no effect on XAF1 expression.Overexpression of XAF1 was more sensitive to U0126-induced apoptosis,whereas down-regulation of XAF1 by antisense reversed U0126-induced inhibition of cell proliferation.Conclusions:XAF1 expression was up-regulated by inhibition of the ERK1/2 pathway through transcriptional regulation,which required de novo protein synthesis.The results suggest that XAF1 mediates apoptosis induced by the ERK1/2 pathway in colon cancer.展开更多
The human RNA methyltransferase like i gene (RNMTL1) is one of thirteen newly discovered geneswithin a 116 Kb segment of the chromosome 17p13.3 that suffers from a high frequent loss of heterozygosityin human hepatoce...The human RNA methyltransferase like i gene (RNMTL1) is one of thirteen newly discovered geneswithin a 116 Kb segment of the chromosome 17p13.3 that suffers from a high frequent loss of heterozygosityin human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlyingtranscription control of the RNMTL1 gene in human cancers, we decline using of the conventional approachwhere the cis-elements bound by the known transcription factors are primary targets, and carried out thesystematic analyses to dissect the promoter structure and identify/characterize the key cis-elements thatare responsible for its strong expression in cell. The molecular approaches applied included 1, the primerextension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a largenumber of deletion and site-specific mutants of the promoter segment for defining the minimal promoterand the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies forreconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that theinteraction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominantrole in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREBelement play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanismunderlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.展开更多
The human RNA methyltransferase like 1 gene (RNMTL1) is one of thirteen newly discovered genes within a 116 Kb segment of the chromosome 17pl3.3 that suffers from a high frequent loss of heterozygosity in human hepato...The human RNA methyltransferase like 1 gene (RNMTL1) is one of thirteen newly discovered genes within a 116 Kb segment of the chromosome 17pl3.3 that suffers from a high frequent loss of heterozygosity in human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlying transcription control of the RNMTL1 gene in human cancers, we decline using of the conventional approach where the cis-elements bound by the known transcription factors are primary targets, and carried out the systematic analyses to dissect the promoter structure and identify/characterize the key cis-elements that are responsible for its strong expression in cell. The molecular approaches applied included 1, the primer extension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a large number of deletion and site-specific mutants of the promoter segment for defining the minimal promoter and the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies for reconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that the interaction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominant role in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREB element play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanism underlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.展开更多
Root architecture is one of the most important agronomic traits that determines rice crop yield. The primary root(PR) absorbs mineral nutrients and provides mechanical support;however, the molecular mechanisms of PR e...Root architecture is one of the most important agronomic traits that determines rice crop yield. The primary root(PR) absorbs mineral nutrients and provides mechanical support;however, the molecular mechanisms of PR elongation remain unclear in rice. Here, the two loss-of-function T-DNA insertion mutants of root length regulator 4(Os RLR4), osrlr4-1 and osrlr4-2 with longer PR, and three Os RLR4 overexpression lines, OE-Os RLR4-1/-2/-3 with shorter PR compared to the wild type/Hwayoung(WT/HY), were identified. Os RLR4 isone of five members of the PRAF subfamily of the regulator chromosome condensation1(RCC1) family. Phylogenetic analysis of Os RLR4 from wild and cultivated rice indicated that it is under selective sweeps, suggesting its potential role in domestication. Os RLR4 controls PR development by regulating auxin accumulation in the PR tip and thus the root apical meristem activity. A series of biochemical and genetic analyses demonstrated that Os RLR4 functions directly upstream of the auxin transporter Os AUX1. Moreover, Os RLR4 interacts with the TRITHORAX-like protein Os Trx1 to promote H3 K4 me3 deposition at the Os AUX1 promoter, thus altering its transcription level. This work provides insight into the cooperation of auxin and epigenetic modifications in regulating root architecture and provides a genetic resource for plant architecture breeding.展开更多
The Y-located testis-specific protein Y-encoded (TSPY) and its X-homologue TSPX originated from the same ancestral gene, but act as a proto-oncogene and a tumor suppressor gene, respectively. TSPY has specialized in m...The Y-located testis-specific protein Y-encoded (TSPY) and its X-homologue TSPX originated from the same ancestral gene, but act as a proto-oncogene and a tumor suppressor gene, respectively. TSPY has specialized in male-specific functions, while TSPX has assumed the functions of the ancestral gene. Both TSPY and TSPX harbor a conserved SET/NAP domain, but are divergent at flanking structures. Specifically, TSPX contains a C-terminal acidic domain, absent in TSPY. They possess contrasting properties, in which TSPY and TSPX, respectively, accelerate and arrest cell proliferation, stimulate and inhibit cyclin B-CDK1 phosphorylation activities, have no effect and promote proteosomal degradation of the viral HBx oncoprotein, and exacerbate and repress androgen receptor (AR) and constitutively active AR variant, such as AR-V7, gene transactivation. The inhibitory domain has been mapped to the carboxyl acidic domain in TSPX, truncation of which results in an abbreviated TSPX exerting positive actions as TSPY. Transposition of the acidic domain to the C-terminus of TSPY results in an inhibitory protein as intact TSPX. Hence, genomic mutations/aberrant splicing events could generate TSPX proteins with truncated acidic domain and oncogenic properties as those for TSPY. Further, TSPY is upregulated by AR and AR-V7 in ligand-dependent and ligand-independent manners, respectively, suggesting the existence of a positive feedback loop between a Y-located proto-oncogene and male sex hormone/receptors, thereby amplifying the respective male oncogenic actions in human cancers and diseases. TSPX counteracts such positive feedback loop. Hence, TSPY and TSPX are homologues on the sex chromosomes that function at the two extremes of the human oncogenic spectrum.展开更多
文摘The human C17orf25 gene (Accession No. AF177342) is one of thirteen genes cloned from a region displaying a high score of loss of heterozygosity within chromosome 17pl3.3 in human hepatocellular carcinoma in China[l]. To unveil the underlying mechanisms for the transcription regulation of this gene and understand its implication to the hepatocellular carcinogenesis, we looked into the relevant aspects by both bioinformatic and experimental executions. We found: 1, The abundant expression of the C17orf25 gene was evident in all the cell lines and tissue samples tested, showing little hepatoma-selectivity; 2, Its transcription starts at a single site, locating at -60 from the translation initiation codon; 3, A 58 bp fragment containing the transcription start, extending from -112 to -55, represents the minimal promoter; 4, The consensus sequence within this fragment recognized by SP1 contributes predominantly to the activity of the minimal promoter; 5, The bioinformatic analysis suggests that the C17orf25 gene may encode a protein in the family of the glyoxalase. Our data has provided some deep insight into both function and regulation of the C1 7orf25 gene in the context of the normal liver and hepatocellular carcinoma.
基金supported by grants from the National High-Tech R&D Program (No. 2011AA100303)the National Key Technology R&D Program (No. 2011BAD19B01)the National Natural Science Foundation of China(No. 31271253)
文摘Background： The p21-activated kinase 1 （PAK1）is essential of microtubule assembly during oocyte meiotic maturation porcine oocytes. for mitosis and plays an important role in the regulatio in mice; however, little is known about its role in Result： Total p21-activated kinase 1 （PAK1） and phosphorylated PAK1 at Thr423 （PAK1^Thr423） were consistently expressed in porcine oocytes from the germinal vesicle （GV） to the second metaphase （MII） stages, but phosphorylation of histone H3 at Serr10 （H3^ser10） was only expressed after the GV stage. Immunofiuorescence analysis revealed that PAK1Thr423 and H3^ser10 colocalized on chromosomes after the GV stage. Blocking of endogenous PAK1^Thr423 by injecting a specific antibody decreased the phosphorylation level of H3^ser10; however, it had no impact on chromatin condensation, meiotic progression, cleavage rate of blastomeres or the rate of blastocyst formation. Conclusion： Phosphorylation of PAK1^Thr423 is a spontaneous activation process and the activated PAK1^Thr423 can promote the phosphorylation of H3^ser10; however, this pathway is not required for meiotic maturation of porcine oocytes or early embryonic development.
基金Shanghai Medical Key Discipline Construction Foundation(05-Ⅲ-005-017).
文摘Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-regulated kinase(ERK)pathway is thought to increase cell proliferation and to protect cells from apoptosis.The aim of the study was to investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.Methods:Four human colon cancer cell lines,HCT1116 and Lovo(wildtype p53),DLD1 and SW1116(mutant p53),were used.Lovo stable transfectants with XAF1 sense and antisense were established.The effects of dominant-negative MEK1(DN-MEK1)and MEK-specific inhibitor U0126 on the ERK signaling pathway and expression of XAF1 and XIAP proteins were determined.The transcription activity of core XAF1 promoter was assessed by dual luciferase reporter assay.Cell proliferation was measured by MTT assay.Apoptosis was determined by Hoechst 33258 staining.Results:U0126 increased the expression of XAF1 in a time-and dose-dependent manner.A similar result was obtained in cells transfected with DN-MEK1 treatment.Conversely,the expression of XIAP was down-regulated.Activity of the putative promoter of the XAF1 gene was significantly increased by U0126 treatment and DN-MEK1 transient transfection.rhEGF-stimulated phosphorylation of ERK appeared to have little or no effect on XAF1 expression.Overexpression of XAF1 was more sensitive to U0126-induced apoptosis,whereas down-regulation of XAF1 by antisense reversed U0126-induced inhibition of cell proliferation.Conclusions:XAF1 expression was up-regulated by inhibition of the ERK1/2 pathway through transcriptional regulation,which required de novo protein synthesis.The results suggest that XAF1 mediates apoptosis induced by the ERK1/2 pathway in colon cancer.
文摘The human RNA methyltransferase like i gene (RNMTL1) is one of thirteen newly discovered geneswithin a 116 Kb segment of the chromosome 17p13.3 that suffers from a high frequent loss of heterozygosityin human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlyingtranscription control of the RNMTL1 gene in human cancers, we decline using of the conventional approachwhere the cis-elements bound by the known transcription factors are primary targets, and carried out thesystematic analyses to dissect the promoter structure and identify/characterize the key cis-elements thatare responsible for its strong expression in cell. The molecular approaches applied included 1, the primerextension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a largenumber of deletion and site-specific mutants of the promoter segment for defining the minimal promoterand the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies forreconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that theinteraction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominantrole in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREBelement play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanismunderlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.
基金This work is supported by the 973 projects of China (G1998051004) to Jingde Zhu and (G199805l200) to Dafang Wan, respectively.Thanks are due to Hongyu Zhang and other mem-bers in Jingde Zhu's lab for assistance and helps onnumerous occasions.
文摘The human RNA methyltransferase like 1 gene (RNMTL1) is one of thirteen newly discovered genes within a 116 Kb segment of the chromosome 17pl3.3 that suffers from a high frequent loss of heterozygosity in human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlying transcription control of the RNMTL1 gene in human cancers, we decline using of the conventional approach where the cis-elements bound by the known transcription factors are primary targets, and carried out the systematic analyses to dissect the promoter structure and identify/characterize the key cis-elements that are responsible for its strong expression in cell. The molecular approaches applied included 1, the primer extension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a large number of deletion and site-specific mutants of the promoter segment for defining the minimal promoter and the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies for reconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that the interaction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominant role in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREB element play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanism underlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.
基金funded by grants from the National Natural Science Foundation of China(32060451)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ19C020001)+2 种基金Inner Mongolia Applied Technology Research and Development Foundation to Y.H.Q.the National Natural Science Foundation of China(31801064)to D.M.L.grants from the Swiss National Funds(31003A-165877/1)to M.G.
文摘Root architecture is one of the most important agronomic traits that determines rice crop yield. The primary root(PR) absorbs mineral nutrients and provides mechanical support;however, the molecular mechanisms of PR elongation remain unclear in rice. Here, the two loss-of-function T-DNA insertion mutants of root length regulator 4(Os RLR4), osrlr4-1 and osrlr4-2 with longer PR, and three Os RLR4 overexpression lines, OE-Os RLR4-1/-2/-3 with shorter PR compared to the wild type/Hwayoung(WT/HY), were identified. Os RLR4 isone of five members of the PRAF subfamily of the regulator chromosome condensation1(RCC1) family. Phylogenetic analysis of Os RLR4 from wild and cultivated rice indicated that it is under selective sweeps, suggesting its potential role in domestication. Os RLR4 controls PR development by regulating auxin accumulation in the PR tip and thus the root apical meristem activity. A series of biochemical and genetic analyses demonstrated that Os RLR4 functions directly upstream of the auxin transporter Os AUX1. Moreover, Os RLR4 interacts with the TRITHORAX-like protein Os Trx1 to promote H3 K4 me3 deposition at the Os AUX1 promoter, thus altering its transcription level. This work provides insight into the cooperation of auxin and epigenetic modifications in regulating root architecture and provides a genetic resource for plant architecture breeding.
文摘The Y-located testis-specific protein Y-encoded (TSPY) and its X-homologue TSPX originated from the same ancestral gene, but act as a proto-oncogene and a tumor suppressor gene, respectively. TSPY has specialized in male-specific functions, while TSPX has assumed the functions of the ancestral gene. Both TSPY and TSPX harbor a conserved SET/NAP domain, but are divergent at flanking structures. Specifically, TSPX contains a C-terminal acidic domain, absent in TSPY. They possess contrasting properties, in which TSPY and TSPX, respectively, accelerate and arrest cell proliferation, stimulate and inhibit cyclin B-CDK1 phosphorylation activities, have no effect and promote proteosomal degradation of the viral HBx oncoprotein, and exacerbate and repress androgen receptor (AR) and constitutively active AR variant, such as AR-V7, gene transactivation. The inhibitory domain has been mapped to the carboxyl acidic domain in TSPX, truncation of which results in an abbreviated TSPX exerting positive actions as TSPY. Transposition of the acidic domain to the C-terminus of TSPY results in an inhibitory protein as intact TSPX. Hence, genomic mutations/aberrant splicing events could generate TSPX proteins with truncated acidic domain and oncogenic properties as those for TSPY. Further, TSPY is upregulated by AR and AR-V7 in ligand-dependent and ligand-independent manners, respectively, suggesting the existence of a positive feedback loop between a Y-located proto-oncogene and male sex hormone/receptors, thereby amplifying the respective male oncogenic actions in human cancers and diseases. TSPX counteracts such positive feedback loop. Hence, TSPY and TSPX are homologues on the sex chromosomes that function at the two extremes of the human oncogenic spectrum.
