Effect of environmental stress responsive transcription factor ATF5 on adipogenesis

肥胖是糖尿病、高血压、高脂血症等代谢综合征的危险因素。肥胖是由脂肪细胞过多引起的，与脂肪细胞的生长和分化有关。另一方面，我发现随着脂肪细胞的分化，ATF5 mRNA水平下降到30%。提示ATF5可能对脂肪细胞分化有重要作用。我发现ATF5 mRNA的表达在多种应激下上调。这说明应激对ATF5表达的改变可能扰乱了ATF5靶基因的表达模式，从而导致ATF5的病理状态。迄今为止，受ATF5调控的基因表达尚不清楚。对这些基因的探索是阐明ATF5功能的有效途径之一。我计划使用SiRNA技术敲低脂肪细胞中ATF5的表达，并通过DNA微阵列分析比较敲低细胞和对照细胞中多种基因的表达模式。一开始，我试图产生有效的SiRNA来表达ATF5。我用转染flag-ATF5表达质粒的细胞检查SiRNA的效率，flag-ATF5蛋白的表达被有效抑制。此外，为了在细胞中外源表达ATF5，我尝试构建腺病毒载体。

Obesity is a risk factor of metabolic syndrome including diabetes, hypertension and hyperlipidemia. Obesity is caused by an excessive adipocytes and related to the cell growth and differentiation of adipocytes. On the other hand, I have found that ATF5 mRNA levels decreases to 30% according to the adipocyte differentiation. This suggests that ATF5 might have a significant function on the adipocyte differentiation. I have found that ATF5 mRNA expression is up-regulated by a variety of stresses. This shows that changes of ATF5 expression by the stresses might disturb the expression patterns of the target genes for ATF5 and leads to the pathological status. Until now, the genes whose expression are regulated by ATF5 are unknown. The exploration of those genes is one of the useful ways for elucidating the functions of ATF5. I planed to knock down the expression of ATF5 in adipocyte using SiRNA technique, and compare the expression pattern of a variety of genes between in knockdown cells and in control cells with DNA microarray analysis. At first, I tried to produce the effective SiRNA for ATF5 expression. I checked the effeciency of the SiRNA using the cells which transfected with the flag-ATF5 exprerssion plasmid, the expression of flag-ATF5 protein was effectively repressed. Furthermore, to express ATF5 in cells exogenously, I tried to construct the adeno virus vector.