为探讨小鼠植入前胚胎组蛋白乙酰化酶GCN5(general control of nucleotide synthesis,GCN5) 和组蛋白去乙酰化酶1(histone deacetyluse1,HDAC1)的表达模式及常规体外培养对它们表达的影响,应用荧光免疫细胞化学技术,检测了体内和体外培...为探讨小鼠植入前胚胎组蛋白乙酰化酶GCN5(general control of nucleotide synthesis,GCN5) 和组蛋白去乙酰化酶1(histone deacetyluse1,HDAC1)的表达模式及常规体外培养对它们表达的影响,应用荧光免疫细胞化学技术,检测了体内和体外培养的小鼠2、4、8细胞期卵裂胚胎、桑葚胚和囊胚GCN5和HDAC1的表达。结果显示,GCN5在体内组各细胞期卵裂胚胎和桑葚胚的细胞浆内均呈高表达,细胞核内未见明显表达,而囊胚细胞的细胞浆和细胞核内均无表达:HDAC1在体内组小鼠2细胞期胚胎中以细胞浆内表达为主,在其他各期胚胎均以细胞核内表达为主．囊胚期内细胞团部分细胞的细胞核内未见HDAC1表达。GCN5在体外组小鼠植入前各期胚胎均不表达,而 HDAC1的表达强度明显低于体内组的。提示体外培养抑制小鼠植入前胚胎GCN5和明显降低 HDAC1的表达,影响胚胎基因的正确性表达。展开更多
MicroRNAs （miRNA） that guide sequence-specific posttranscriptional gene silencing play an important role in gene expression required for both developmental processes and responses to environmental conditions in plan...MicroRNAs （miRNA） that guide sequence-specific posttranscriptional gene silencing play an important role in gene expression required for both developmental processes and responses to environmental conditions in plants. However, little is known about the transcriptional and posttranscriptional regulation of miRNA expression. Histone acetylation plays an important role in chromatin remodeling and is required for gene activation. By analyzing the accumulation of subset of miRNAs and the corresponding primary miRNAs in mutants of Arabidopsis, we show that histone acetyltransferase GCN5 （General control non-repressed protein 5） has a general repressive effect on miRNA production, while it is required for the expression of a subset of （e.g. stress-inducible） MIRNA genes. The general negative function of GCN5 in miRNA production is likely achieved through an indirect repression of the miRNA machinery genes such as DICER LIKE1 （DCL1）, SERRATE （SE）, HYPONASTIC LEAVES1 （HYL1） and ARGONAUTE1 （AGO1）. Chromatin immunoprecipitation assays revealed that GCN5 targets to a subset of MIRNA genes and is required for acetylation of histone H3 lysine 14 at these loci. Moreover, inhibition of histone deacetylation by trichostatin A treatment or in histone deacetylase gene mutants impaired the accumulation of certain miRNAs. These data together suggest that Arabidopsis GCN5 interferes with the miRNA pathway at both the transcriptional and posttranscriptional levels and histone acetylation/deacetylation is an epigenetic mechanism involved in the regulation of miRNA production.展开更多
Hepatitis B virus （HBV） biosynthesis is primarily restricted to hepatocytes due to the governing of liver-enriched nuclear receptors （NRs） on viral RNA synthesis. The liver-enriched NR hepatocyte nuclear factor 4...Hepatitis B virus （HBV） biosynthesis is primarily restricted to hepatocytes due to the governing of liver-enriched nuclear receptors （NRs） on viral RNA synthesis. The liver-enriched NR hepatocyte nuclear factor 4α （HNF4α, the key regulator of genes implicated in hepatic glucose metabolism, is also a primary determinant of HBV pregenomic RNA synthesis and HBV replication. Peroxisome proliferator-activated receptor-r coactivator la （PGCla） coactivates and further enhances the effect of HNF4α on HBV biosynthesis. Here, we showed that the acetyltransferase General Control Non-repressed Protein 5 （GCN5） acetylated PGC 1 α, leading to alteration of PGC 1 α from a transcriptionally active state into an inactive state. As a result, the coactivation activity of PGCla on HBV transcription and replication was suppressed. Apparently, an acetylation site mutant of PGC 1 α （PGC 1 αR13） still had coactivation activity as GCN5 could not suppress the coactivation activity of the mutant. Moreover, a catalytically inactive acetyltransferase mutant GCN5m, due to the loss of acetylation activity, failed to inhibit the coactivation function of PGClα in HBV biosynthesis. Our results demonstrate that GCN5, through its acetyltransferase activity, inhibits PGCla-induced enhancement of HBV transcription and replication both in vitro and in vivo.展开更多
目的:研究沉默大鼠肾组织中通用控制核苷酸合成5(general control nonderepressible 5,GCN5)基因、性别决定区Y框蛋白9(SRY related HMG box-9,SOX9)基因对Thy-1肾炎(Thy-1 nephritis,Thy-1N)大鼠肾组织内转化生长因子-β1(transforming...目的:研究沉默大鼠肾组织中通用控制核苷酸合成5(general control nonderepressible 5,GCN5)基因、性别决定区Y框蛋白9(SRY related HMG box-9,SOX9)基因对Thy-1肾炎(Thy-1 nephritis,Thy-1N)大鼠肾组织内转化生长因子-β1(transforming growth factor-β1,TGF-β1)生成的影响。方法:分别用慢病毒(lentivirus,LV)包装GCN5和SOX9发夹状小干扰RNA(shRNA),即制备LV-shGCN5和LV-shSOX9重组病毒。然后行大鼠肾动脉灌注术将LV-shGCN5和LV-shSOX9分别导入大鼠肾脏,再经尾静脉注射兔抗大鼠胸腺细胞抗血清(anti-thymocyte serum,ATS)复制Thy-1N模型。在注射ATS后3 h,取大鼠肾组织,用RTPCR和Western blot检查各组大鼠肾组织中GCN5和SOX9的mRNA及蛋白表达水平,以验证干扰效果及GCN5、SOX9对TGF-β1产生的影响。结果:利用肾动脉灌注术将LV-shGCN5或LV-shSOX9重组病毒导入大鼠肾组织后,不仅能有效沉默相应的靶基因,而且还能下调TGF-β1的表达。结论:沉默大鼠肾组织中GCN5或SOX9基因后能显著抑制Thy-1N大鼠肾内TGF-β1的生成。展开更多
该文研究了Islet-1诱导间充质干细胞C3H10T1/2向心肌样细胞特异分化过程中Akt与Islet-1/GCN5(general control of amino acid biosynthesis protein 5)蛋白质复合体的关系,进一步探讨了间充质干细胞诱导分化的调控机制。该文用过表达Isl...该文研究了Islet-1诱导间充质干细胞C3H10T1/2向心肌样细胞特异分化过程中Akt与Islet-1/GCN5(general control of amino acid biosynthesis protein 5)蛋白质复合体的关系,进一步探讨了间充质干细胞诱导分化的调控机制。该文用过表达Islet-1基因的慢病毒感染小鼠间充质干细胞C3H10T1/2,倒置显微镜观察细胞形态,免疫荧光检测Islet-1、c Tn T(cardiac troponin T)、Connexin43蛋白质水平,免疫共沉淀技术(Co IP)检测激活或抑制Akt的情况下Islet-1与GCN5的结合情况。结果表明,感染过表达Islet-1基因慢病毒的C3H10T1/2细胞形态出现心肌样变,Islet-1、c Tn T、Connexin43蛋白质水平均高于未感染组。在Islet-1蛋白质高峰的第三周时间点,激活或抑制Akt的情况下,Islet-1与GCN5的结合量分别低于或高于未加药处理的细胞组(P<0.05)。该研究结果表明,在诱导间充质干细胞C3H10T1/2向心肌样细胞特异分化过程中Akt的活性与Islet-1/GCN5蛋白质的结合量存在相互拮抗的关系。展开更多
Deregulated c-Myc expression is a hallmark of many human cancers. We have recently identified a role of mammalian homolog of yeast SPT-ADA-GCN5-acetyltransferas(SAGA) complex component, SAGAassociated factor 29(SGF29)...Deregulated c-Myc expression is a hallmark of many human cancers. We have recently identified a role of mammalian homolog of yeast SPT-ADA-GCN5-acetyltransferas(SAGA) complex component, SAGAassociated factor 29(SGF29), in regulating the c-Myc overexpression. Here, we discuss the molecular nature of SFG29 in SPT3-TAF9-GCN5-acetyltransferase complex, a counterpart of yeast SAGA complex, and the mechanism through which the elevated SGF29 expression contribute to oncogenic potential of c-Myc in hepatocellularcarcinoma(HCC). We propose that the upstream regulation of SGF29 elicited by sexdetermining region Y(Sry) is also augmented in HCC. We hypothesize that c-Myc elevation driven by the deregulated Sry and SGF29 pathway is implicated in the male specific acquisition of human HCCs.展开更多
文摘为探讨小鼠植入前胚胎组蛋白乙酰化酶GCN5(general control of nucleotide synthesis,GCN5) 和组蛋白去乙酰化酶1(histone deacetyluse1,HDAC1)的表达模式及常规体外培养对它们表达的影响,应用荧光免疫细胞化学技术,检测了体内和体外培养的小鼠2、4、8细胞期卵裂胚胎、桑葚胚和囊胚GCN5和HDAC1的表达。结果显示,GCN5在体内组各细胞期卵裂胚胎和桑葚胚的细胞浆内均呈高表达,细胞核内未见明显表达,而囊胚细胞的细胞浆和细胞核内均无表达:HDAC1在体内组小鼠2细胞期胚胎中以细胞浆内表达为主,在其他各期胚胎均以细胞核内表达为主．囊胚期内细胞团部分细胞的细胞核内未见HDAC1表达。GCN5在体外组小鼠植入前各期胚胎均不表达,而 HDAC1的表达强度明显低于体内组的。提示体外培养抑制小鼠植入前胚胎GCN5和明显降低 HDAC1的表达,影响胚胎基因的正确性表达。
文摘MicroRNAs （miRNA） that guide sequence-specific posttranscriptional gene silencing play an important role in gene expression required for both developmental processes and responses to environmental conditions in plants. However, little is known about the transcriptional and posttranscriptional regulation of miRNA expression. Histone acetylation plays an important role in chromatin remodeling and is required for gene activation. By analyzing the accumulation of subset of miRNAs and the corresponding primary miRNAs in mutants of Arabidopsis, we show that histone acetyltransferase GCN5 （General control non-repressed protein 5） has a general repressive effect on miRNA production, while it is required for the expression of a subset of （e.g. stress-inducible） MIRNA genes. The general negative function of GCN5 in miRNA production is likely achieved through an indirect repression of the miRNA machinery genes such as DICER LIKE1 （DCL1）, SERRATE （SE）, HYPONASTIC LEAVES1 （HYL1） and ARGONAUTE1 （AGO1）. Chromatin immunoprecipitation assays revealed that GCN5 targets to a subset of MIRNA genes and is required for acetylation of histone H3 lysine 14 at these loci. Moreover, inhibition of histone deacetylation by trichostatin A treatment or in histone deacetylase gene mutants impaired the accumulation of certain miRNAs. These data together suggest that Arabidopsis GCN5 interferes with the miRNA pathway at both the transcriptional and posttranscriptional levels and histone acetylation/deacetylation is an epigenetic mechanism involved in the regulation of miRNA production.
基金supported by grants from the National Major Science and Technology Special Projects for Infectious Diseases of China (2012ZX10004503-008, 2012ZX10001006-002,and 2012ZX10002006-002)
文摘Hepatitis B virus （HBV） biosynthesis is primarily restricted to hepatocytes due to the governing of liver-enriched nuclear receptors （NRs） on viral RNA synthesis. The liver-enriched NR hepatocyte nuclear factor 4α （HNF4α, the key regulator of genes implicated in hepatic glucose metabolism, is also a primary determinant of HBV pregenomic RNA synthesis and HBV replication. Peroxisome proliferator-activated receptor-r coactivator la （PGCla） coactivates and further enhances the effect of HNF4α on HBV biosynthesis. Here, we showed that the acetyltransferase General Control Non-repressed Protein 5 （GCN5） acetylated PGC 1 α, leading to alteration of PGC 1 α from a transcriptionally active state into an inactive state. As a result, the coactivation activity of PGCla on HBV transcription and replication was suppressed. Apparently, an acetylation site mutant of PGC 1 α （PGC 1 αR13） still had coactivation activity as GCN5 could not suppress the coactivation activity of the mutant. Moreover, a catalytically inactive acetyltransferase mutant GCN5m, due to the loss of acetylation activity, failed to inhibit the coactivation function of PGClα in HBV biosynthesis. Our results demonstrate that GCN5, through its acetyltransferase activity, inhibits PGCla-induced enhancement of HBV transcription and replication both in vitro and in vivo.
文摘该文研究了Islet-1诱导间充质干细胞C3H10T1/2向心肌样细胞特异分化过程中Akt与Islet-1/GCN5(general control of amino acid biosynthesis protein 5)蛋白质复合体的关系,进一步探讨了间充质干细胞诱导分化的调控机制。该文用过表达Islet-1基因的慢病毒感染小鼠间充质干细胞C3H10T1/2,倒置显微镜观察细胞形态,免疫荧光检测Islet-1、c Tn T(cardiac troponin T)、Connexin43蛋白质水平,免疫共沉淀技术(Co IP)检测激活或抑制Akt的情况下Islet-1与GCN5的结合情况。结果表明,感染过表达Islet-1基因慢病毒的C3H10T1/2细胞形态出现心肌样变,Islet-1、c Tn T、Connexin43蛋白质水平均高于未感染组。在Islet-1蛋白质高峰的第三周时间点,激活或抑制Akt的情况下,Islet-1与GCN5的结合量分别低于或高于未加药处理的细胞组(P<0.05)。该研究结果表明,在诱导间充质干细胞C3H10T1/2向心肌样细胞特异分化过程中Akt的活性与Islet-1/GCN5蛋白质的结合量存在相互拮抗的关系。
基金Supported by The "Academic Frontier" project for Private University:a matching fund subsidy from MEXT(Ministry of Education,Culture,Sports,Science and Technology),2006-2010(to Tashiro F)
文摘Deregulated c-Myc expression is a hallmark of many human cancers. We have recently identified a role of mammalian homolog of yeast SPT-ADA-GCN5-acetyltransferas(SAGA) complex component, SAGAassociated factor 29(SGF29), in regulating the c-Myc overexpression. Here, we discuss the molecular nature of SFG29 in SPT3-TAF9-GCN5-acetyltransferase complex, a counterpart of yeast SAGA complex, and the mechanism through which the elevated SGF29 expression contribute to oncogenic potential of c-Myc in hepatocellularcarcinoma(HCC). We propose that the upstream regulation of SGF29 elicited by sexdetermining region Y(Sry) is also augmented in HCC. We hypothesize that c-Myc elevation driven by the deregulated Sry and SGF29 pathway is implicated in the male specific acquisition of human HCCs.
