Ordahl C P
Dev Biol. 1986 Oct;117(2):488-92. doi: 10.1016/0012-1606(86)90315-5.
The relative steady-state abundance of cardiac and skeletal alpha-actin mRNAs at different stages of embryonic skeletal and cardiac (striated) muscle development was determined by a reverse transcriptase extension assay employing an single oligonucleotide primer complementary to a perfectly conserved region near the 5' end of both mRNAs. Both mRNAs were found to be present at every stage of embryonic striated muscle development tested, including the earliest assayable stages of limb muscle and cardiac muscle development. At early stages of skeletal muscle development the two mRNAs are present at similar levels while at later stages the abundance of the skeletal alpha-actin mRNA far exceeds that of the cardiac alpha-actin mRNA. Both mRNAs are also present at similar levels throughout embryonic cardiac muscle development while in adult cardiac muscle the cardiac alpha-actin mRNA predominates over the skeletal alpha-actin mRNA. These results for early embryonic striated muscle, in combination with previous results with late embryonic and adult striated muscle, indicate that both genes are coexpressed throughout striated muscle ontogeny. These two genes may not, therefore, be regulated under unique tissue-specific regulatory programs but each may have acquired regulatory elements which confer important quantitative differences in their level of expression in mature striated muscle cells.
采用逆转录酶延伸分析法，使用与两种mRNA 5'端附近完全保守区域互补的单一寡核苷酸引物，测定了胚胎骨骼肌和心肌（横纹肌）发育不同阶段心脏和骨骼肌α-肌动蛋白mRNA的相对稳态丰度。在所测试的胚胎横纹肌发育的每个阶段都发现了这两种mRNA，包括肢体肌肉和心肌发育的最早可检测阶段。在骨骼肌发育的早期阶段，这两种mRNA以相似的水平存在，而在后期阶段，骨骼肌α-肌动蛋白mRNA的丰度远远超过心脏α-肌动蛋白mRNA。在整个胚胎心肌发育过程中，这两种mRNA也以相似的水平存在，而在成年心肌中，心脏α-肌动蛋白mRNA的含量超过骨骼肌α-肌动蛋白mRNA。早期胚胎横纹肌的这些结果，与先前关于晚期胚胎和成年横纹肌的结果相结合，表明这两个基因在整个横纹肌个体发育过程中共同表达。因此，这两个基因可能不是在独特的组织特异性调控程序下进行调控的，而是每个基因可能都获得了调控元件，这些元件在成熟横纹肌细胞中的表达水平上产生了重要的数量差异。
