TISSUE-SPECIFIC CONTROL OF MUSCLE GENE EXPRESSION

骨骼肌的分化伴随着骨骼肌的 肌节蛋白的诱导。 的外观 蛋白质之前， 相应的mRNA反映了转录水平的增加， 活动 反过来，这种转录增加依赖于 存在正确的顺式和反式作用元件。 我们 最近在骨骼肌中发现了一种核因子， 以高亲和力特异性结合上游序列 位于编码肌节蛋白的基因的5'端的元件， α-肌动蛋白和肌球蛋白轻链2。 这一发现支持了 肌节蛋白协同诱导的假说 通过有限数量的反式作用因子的作用。 在 在本申请中，我们建议扩展这些观察 通过（i）描述上游肌肉特异性的作用， 调控肌肉基因表达的序列元件（ii） 骨骼肌核因子的纯化和表征 （iii）开发体外转录 严格评估监管职能的制度 肌肉特异性因素 我们的目标，反式作用的纯化 因素和DNA结合序列的作用的阐明 在组织特异性基因调控中， 理解最终导致 在成肌细胞分化中。

Skeletal muscle differentiation is accompanied by the coordinate induction of sarcomeric proteins. The appearance of these proteins is preceded by a rise in the abundance of the corresponding mRNAs reflecting an increase in transcriptional activity. This transcriptional increase, in turn, is dependent upon the presence of the correct cis- and trans- acting elements. We have recently identified a nuclear factor in skeletal muscle which binds specifically and with high affinity to an upstream sequence element located 5' to the genes encoding the sarcomeric proteins, a-actin and myosin light chain 2. This finding lends support to the hypothesis that the sarcomeric proteins are coordinately induced through the action of a limited number of trans-acting factors. In the present application, we propose to extend these observations by (i) Delineating the role of the upstream muscle specific, sequence element in the regulation muscle gene expression (ii) Purifying and characterizing the skeletal muscle nuclear factor(s) that bind to this sequence (iii) Developing an in vitro transcription system with which to rigorously assess the regulatory function of muscle specific factors. Our goal, the purification of trans-acting factors and the elucidation of the role of DNA binding sequences in tissue-specific gene regulation, is the first step in understanding the developmental cascade which eventually results in myoblast differentiation.