alpha-skeletal and alpha-cardiac actin genes are coexpressed in adult human skeletal muscle and heart
alpha-skeletal and alpha-cardiac actin genes are coexpressed in adult human skeletal muscle and heart
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α-骨骼和α-心脏肌动蛋白基因在成人骨骼肌和心脏中共表达
DOI：
10.1128/mcb.3.11.1985-1995.1983
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发表时间：
1983
影响因子：
5.3
通讯作者：
L. Kedes
中科院分区：
文献类型：
--
作者：
P. Gunning;P. Ponte;H. Blau;L. Kedes
我们确定了先前从成人肌肉 cDNA 文库中分离出的 30 个肌动蛋白 cDNA 克隆编码的肌动蛋白同种型。使用源自α-骨骼、β-和γ-肌动蛋白cDNA以及α-心脏肌动蛋白基因组克隆的3'非翻译区探针，我们发现28个cDNA对应于α-骨骼肌动蛋白转录物。然而，出乎意料的是，其余两个 cDNA 克隆被证明源自 α-心脏肌动蛋白 mRNA。序列分析证实这两个骨骼肌α-心肌肌动蛋白cDNA源自克隆的α-心肌肌动蛋白基因的转录本。对人骨骼肌中肌动蛋白同种型 mRNA 表达的直接测量表明，α-心肌肌动蛋白 mRNA 的表达水平是 α-骨骼肌肌动蛋白水平的 5%。此外，骨骼肌中表达的α-心肌肌动蛋白基因与在人类心脏中产生α-心肌肌动蛋白mRNA的基因相同。同样令人惊讶的是，我们发现 α-骨骼肌动蛋白 mRNA 约占成人心脏肌动蛋白总 mRNA 的一半。成人骨骼肌和成人心脏中总肌动蛋白 mRNA 水平的比较表明，每微克总细胞 RNA，骨骼肌中的稳态水平大约是心脏中的两倍。因此，在骨骼肌和心脏中，两种肌节肌动蛋白 mRNA 同种型都是相当丰富的转录物。我们得出的结论是，α-骨骼肌动蛋白基因和α-心脏肌动蛋白基因在成人横纹肌中作为肌动蛋白对共表达。由于已知平滑肌肌动蛋白（主动脉和胃）和细胞质肌动蛋白（β和γ）分别在平滑肌和非肌肉细胞中共表达，因此我们假设肌动蛋白对的共表达可能是哺乳动物肌动蛋白基因在所有组织中表达的共同特征。
We determined the actin isotypes encoded by 30 actin cDNA clones previously isolated from an adult human muscle cDNA library. Using 3' untranslated region probes derived from alpha-skeletal, beta- and gamma-actin cDNAs and from an alpha-cardiac actin genomic clone, we showed that 28 of the cDNAs correspond to alpha-skeletal actin transcripts. Unexpectedly, however, the remaining two cDNA clones proved to derive from alpha-cardiac actin mRNA. Sequence analysis confirmed that the two skeletal muscle alpha-cardiac actin cDNAs are derived from transcripts of the cloned alpha-cardiac actin gene. Direct measurements of actin isotype mRNA expression in human skeletal muscle showed that alpha-cardiac actin mRNA is expressed at 5% the level of alpha-skeletal actin. Furthermore, the alpha-cardiac actin gene expressed in skeletal muscle is the same gene which produces alpha-cardiac actin mRNA in the human heart. Of equal surprise, we found that alpha-skeletal actin mRNA accounts for about half of the total actin mRNA in adult heart. Comparison of total actin mRNA levels in adult skeletal muscle and adult heart revealed that the steady-state levels in skeletal muscle are about twofold greater, per microgram of total cellular RNA, than those in heart. Thus, in skeletal muscle and in heart, both of the sarcomeric actin mRNA isotypes are quite abundant transcripts. We conclude that alpha-skeletal and alpha-cardiac actin genes are coexpressed as an actin pair in human adult striated muscles. Since the smooth-muscle actins (aortic and stomach) and the cytoplasmic actins (beta and gamma) are known to be coexpressed in smooth muscle and nonmuscle cells, respectively, we postulate that coexpression of actin pairs may be a common feature of mammalian actin gene expression in all tissues.