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Cooperativity of sequence elements mediates tissue specificity of the rat insulin II gene. 总被引:9,自引:5,他引:4
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The 5'-flanking region of the rat insulin II gene (-448 to +50) is sufficient for tissue-specific expression. To further determine the tissue-specific cis-acting element(s), important sequences defined by linker-scanning mutagenesis were placed upstream of a heterologous promoter and transfected into insulin-producing and -nonproducing cells. Rat insulin promoter element 3 (RIPE3), which spans from -125 to -86, was shown to confer beta-cell-specific expression in either orientation. However, two subregions of RIPE3, RIPE3a and RIPE3b (defined by linker-scanning mutations), displayed only marginal activities. These results suggest that the two subregions cooperate to confer tissue specificity, presumably via their cognate binding factors. 相似文献
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The islet beta cell-enriched RIPE3b1/Maf transcription factor regulates pdx-1 expression 总被引:3,自引:0,他引:3
Samaras SE Zhao L Means A Henderson E Matsuoka TA Stein R 《The Journal of biological chemistry》2003,278(14):12263-12270
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Identification of a pancreatic beta-cell insulin gene transcription factor that binds to and appears to activate cell-type-specific expression: its possible relationship to other cellular factors that bind to a common insulin gene sequence. 总被引:21,自引:13,他引:8
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J Whelan S R Cordle E Henderson P A Weil R Stein 《Molecular and cellular biology》1990,10(4):1564-1572
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Zhao L Cissell MA Henderson E Colbran R Stein R 《The Journal of biological chemistry》2000,275(14):10532-10537
Glucose-stimulated and pancreatic islet beta cell-specific expression of the insulin gene is mediated in part by the C1 DNA-element binding complex, termed RIPE3b1. In this report, we define the molecular weight range of the protein(s) that compose this beta cell-enriched activator complex and show that protein phosphatase treatment inhibits RIPE3b1 DNA binding activity. Fractionation of beta cell nuclear extracts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that RIPE3b1 binding was mediated by a protein(s) within the 37-49-kDa ranges. Direct analysis of the proteins within the RIPE3b1 complex by ultraviolet light cross-linking analysis identified three binding species of approximately 51, 45, and 38 kDa. Incubating beta cell nuclear extracts with either calf alkaline phosphatase or a rat brain phosphatase preparation dramatically reduced RIPE3b1 DNA complex formation. Phosphatase inhibition of RIPE3b1 binding was prevented by sodium pyrophosphate, a general phosphatase inhibitor. We discuss how changes in the phosphorylation status of the RIPE3b1 activator may influence its DNA binding activity. 相似文献
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MafA is a glucose-regulated and pancreatic beta-cell-specific transcriptional activator for the insulin gene 总被引:12,自引:0,他引:12
Kataoka K Han SI Shioda S Hirai M Nishizawa M Handa H 《The Journal of biological chemistry》2002,277(51):49903-49910
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为了解葡萄糖和胰岛素调控小鼠ob基因表达调控的机制,应用荧光素酶报告基因、凝胶迁移率变动分析(gel mobility shift assays,GMSA)、DNase I足迹分析和突变分析技术对小鼠ob基因启动子-1719~-1452bp之间存在负调控元件、GLRE和IRE。GMSA结果显示葡萄糖和胰岛素抑制转录因子与顺式元件。DNase I足迹分析和突变分析显示此结合区这AGCAAAA,位于ob 相似文献