Garfinkel L I, Periasamy M, Nadal-Ginard B
J Biol Chem. 1982 Sep 25;257(18):11078-86.
A library of cDNA clones was constructed from adult rat skeletal muscle mRNA, from which a set of contractile protein clones was selected. These clones were identified by sequencing the cDNA inserts and comparing the derived amino acid sequences with published sequences of rabbit contractile proteins. In this manner, clones corresponding to myosin light chains 1, 2, and 3, troponin-C, troponin-T, alpha-tropomyosin, and alpha-actin were identified. A high degree of amino acid sequence conservation was found upon comparison of the rat and rabbit proteins. Using the cDNA clone panel, we analyzed the expression of abundant rat muscle mRNAs. We show that abundant rat muscle mRNAs can be classified into four developmentally regulated groups, based upon their expression at different stages of myogenesis. One class of mRNAs is expressed during all stages of muscle development. Since these mRNAs are also present in nonmuscle tissues, we conclude that they code for housekeeping proteins. The second class of mRNAs is present in both embryonic and adult muscle, while a third class of mRNAs is expressed only in adult muscle. A small number of mRNAs, which are present at greater levels in undifferentiated myoblasts than in adult muscle, comprise a fourth class. These results suggest the existence of at least four modes of gene control during myogenesis.
从成年大鼠骨骼肌mRNA构建了一个cDNA克隆文库，从中挑选出一组收缩蛋白克隆。通过对cDNA插入片段进行测序，并将推导的氨基酸序列与已发表的兔收缩蛋白序列进行比较，来鉴定这些克隆。通过这种方式，鉴定出了与肌球蛋白轻链1、2和3、肌钙蛋白C、肌钙蛋白T、α-原肌球蛋白和α-肌动蛋白相对应的克隆。比较大鼠和兔的蛋白质时发现氨基酸序列具有高度保守性。利用cDNA克隆库，我们分析了大鼠丰富肌肉mRNA的表达情况。我们发现，根据大鼠丰富肌肉mRNA在肌生成不同阶段的表达情况，可将其分为四个发育调控组。一类mRNA在肌肉发育的所有阶段都有表达。由于这些mRNA也存在于非肌肉组织中，我们得出结论，它们编码管家蛋白。第二类mRNA存在于胚胎肌肉和成年肌肉中，而第三类mRNA仅在成年肌肉中表达。一小部分mRNA在未分化的成肌细胞中的水平高于成年肌肉，它们构成了第四类。这些结果表明在肌生成过程中至少存在四种基因控制模式。
