GLUCOSE SIGNALING AND REGULATION OF GENE EXPRESSION IN 3T3-L1 ADIPOCYTES

本项目的目的是评估葡萄糖的调节 葡萄糖转运蛋白基因表达，以确定 CCAAT/增强子结合蛋白（C/EBP）参与控制 葡萄糖转运蛋白基因，并测试是否非氧化分支 戊糖磷酸途径的可能是关键的葡萄糖介导的 代谢基因表达 完全分化的3 T3-L1脂肪细胞， 培养物经受四种实验条件：升高的葡萄糖 喂食（25 mM），葡萄糖剥夺，使用非代谢葡萄糖 类似物和木糖醇。 进行北方印迹分析以确定 各种代谢调节基因的表达水平。 一 C/EBPalpha和GLUT-4 mRNA水平的协调调节是 在所有测试的培养条件下观察到。 相反，C/EBPa和 GLUT-1表达在实验过程中变化不大， 葡萄糖饥饿诱导gadd 153基因表达上调。 看来葡萄糖磷酸化为葡萄糖-6-磷酸是 它对C/EBP的转录作用是必不可少的 GLUT-4基因 磷酸戊糖途径的非氧化分支 参与葡萄糖介导的基因表达调控， 提出了

The purpose of this project is to assess the regulation of glucose transporter gene expression by glucose, to identify the CCAAT/enhancer-binding proteins (C/EBP) implicated in the control of glucose transporter genes, and to test whether the nonoxidative branch of the pentose phosphate pathway might be critical for glucose-mediated metabolic gene expression. Fully-differentiated 3T3-L1 adipocytes in culture were subjected to four experimental conditions: elevated glucose feeding (25mM), glucose deprivation, use of non-metabolized glucose analogs, and xylitol. Northern blot analysis were conducted to determine the level of expression of various metabolic regulation genes. A coordinate regulation of C/EBPalpha and GLUT-4 mRNA levels was observed in all the culture conditions tested. In contrast, C/EBPa and GLUT-1 expression changed little over the course of the experiments while gadd153 gene was induced to high level in response to glucose starvation. It appears that phosphorylation of glucose to glucose-6-phosphate is indispensable for its transcriptional action on C/EBP and GLUT-4 genes. Evidence that the non-oxidative branch of the pentose phosphate pathway is involved in glucose-mediated regulation of gene expression is presented.