Cellular localization of muscle and nonmuscle actin mRNAs in chicken primary myogenic cultures: the induction of alpha-skeletal actin mRNA is regulated independently of alpha-cardiac actin gene expression.
Cellular localization of muscle and nonmuscle actin mRNAs in chicken primary myogenic cultures: the induction of alpha-skeletal actin mRNA is regulated independently of alpha-cardiac actin gene expression.
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DOI：
10.1083/jcb.106.6.2077
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发表时间：
1988-06
期刊：
影响因子：
--
通讯作者：
Schwartz RJ
中科院分区：
文献类型：
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作者：
Hayward LJ;Zhu YY;Schwartz RJ
与β-、α-心脏和α-骨骼肌动蛋白mRNA的3'非翻译区互补的特异性DNA片段被用作原位杂交探针，以检查这些mRNA在原代生肌培养物中的差异表达和分布。我们证明，来自第3天分离的胚胎体节的融合前双极形细胞相当于来自胚胎第11-12天胸肌组织的成肌细胞的α-心脏肌动蛋白基因的表达。原代肌肉培养物中存在的成纤维细胞未被α-心脏肌动蛋白基因探针标记。由于几乎所有的双极细胞融合前表达α-心脏肌动蛋白mRNA，我们认为，双极表型可能区分一个承诺肌源性细胞类型。相比之下，α-骨骼肌动蛋白mRNA仅在多核肌管中积累，并且似乎独立于α-心脏肌动蛋白基因进行调节。α-骨骼肌动蛋白mRNA而非α-心脏肌动蛋白mRNA的积累可以通过在Ca 2+缺乏培养基中生长而被阻断，这阻止了成肌细胞融合。因此，α-心脏，然后α-骨骼肌动蛋白mRNA的顺序出现可能是由于终末分化过程中出现的因素。最后，β-肌动蛋白mRNA位于成纤维细胞和成肌细胞中，但在成肌细胞融合过程中含量减少，并且不存在于分化的肌管中。看来，在原代肌源性培养物中，两种不同的α-横纹肌动蛋白mRNA种类的异步阶段依赖性诱导与非肌肉β-肌动蛋白基因的去诱导同时发生。
Specific DNA fragments complementary to the 3' untranslated regions of the beta-, alpha-cardiac, and alpha-skeletal actin mRNAs were used as in situ hybridization probes to examine differential expression and distribution of these mRNAs in primary myogenic cultures. We demonstrated that prefusion bipolar-shaped cells derived from day 3 dissociated embryonic somites were equivalent to myoblasts derived from embryonic day 11-12 pectoral tissue with respect to the expression of the alpha-cardiac actin gene. Fibroblasts present in primary muscle cultures were not labeled by the alpha-cardiac actin gene probe. Since virtually all of the bipolar cells express alpha-cardiac actin mRNA before fusion, we suggest that the bipolar phenotype may distinguish a committed myogenic cell type. In contrast, alpha-skeletal actin mRNA accumulates only in multinucleated myotubes and appears to be regulated independently from the alpha-cardiac actin gene. Accumulation of alpha- skeletal but not alpha-cardiac actin mRNA can be blocked by growth in Ca2+-deficient medium which arrests myoblast fusion. Thus, the sequential appearance of alpha-cardiac and then alpha-skeletal actin mRNA may result from factors that arise during terminal differentiation. Finally, the beta-actin mRNA was located in both fibroblasts and myoblasts but diminished in content during myoblast fusion and was absent from differentiated myotubes. It appears that in primary myogenic cultures, an asynchronous stage-dependent induction of two different alpha-striated actin mRNA species occurs concomitant with the deinduction of the nonmuscle beta-actin gene.