DIFFERENTIAL PATTERNS OF TRANSCRIPT ACCUMULATION DURING HUMAN MYOGENESIS
DIFFERENTIAL PATTERNS OF TRANSCRIPT ACCUMULATION DURING HUMAN MYOGENESIS
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DOI：
10.1128/mcb.7.11.4100
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发表时间：
1987-11-01
影响因子：
5.3
通讯作者：
KEDES, L
中科院分区：
文献类型：
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作者：
GUNNING, P;HARDEMAN, E;KEDES, L
我们评估了肌肉特异性基因在人类肌肉形成过程中显示相同mRNA积累模式的程度。从成人骨骼肌中分离的克隆卫星细胞在培养中扩增，并在15天的时间内从低、高融合细胞和融合培养中分离RNA。将这些样本中超过20种不同转录本的积累与胎儿和成人骨骼肌中的积累进行了比较。碳酸酐酶3、肌红蛋白、HSP83和编码8种未知蛋白的mrna在人肌源性培养物中的表达进行了检测。一般来说，大多数mrna在融合后被诱导表达形成肌管。然而，有几个例外，包括碳酸酐酶和肌红蛋白，在早期肌管中没有检测到表达。所有转录本的比较显示很少，如果有的话，相同的mRNA积累模式。同样在非肌肉细胞中表达的mrna也出现了类似的变异性。编码。α的mrna的积累。骨骼,.alpha。心脏,度量。-和。gamma。-肌动蛋白，总肌凝蛋白重链，和。-和。beta。-微管蛋白也表现出不协调调节，这对肌节组装具有重要意义。心肌肌动蛋白是唯一在低融合细胞中检测到的肌肉特异性转录物，是主要的α。-肌动蛋白mRNA。骨肌动蛋白在融合培养中短暂诱导，然后减少一个数量级。肌球蛋白重链mRNA总积累滞后于-肌动蛋白。而度量。-和。gamma。-actin在融合开始后急剧下降，此后没有变化。-和。beta。-微管蛋白在培养过程中瞬间被诱导到高水平。我们得出的结论是，每个基因可能都有自己独特的转录积累决定因素，肌肉的表型可能不是由哪些基因活跃或沉默决定的，而是由它们的转录水平被调节的程度决定的。最后，我们观察到肌管培养中建立的转录物积累模式与假设一致，并且从成人组织中分离的成肌细胞概括了肌源性发育程序。然而，我们也在高融合成肌细胞培养中检测到成人骨骼肌特异性转录物的短暂出现。这表明，这些成肌细胞的初始分化可能反映了一个比简单的发育重演更复杂的过程。
We evaluated the extent to which muscle-specific genes display identical patterns of mRNA accumulation during human myogenesis. Cloned satellite cells isolated from adult human skeletal muscle were expanded in culture, and RNA was isolated from low- and high-confluence cells and from fusing cultures over a 15-day time course. The accumulation of over 20 different transcripts was compared in these samples with that in fetal and adult human skeletal muscle. The expression of carbonic anhydrase 3, myoglobin, HSP83, and mRNAs encoding eight unknown proteins were examined in human myogenic cultures. In general, the expression of most of the mRNAs was induced after fusion to form myotubes. However, several exceptions, including carbonic anhydrase and myoglobin, showed no detectable expression in early myotubes. Comparison of all transcripts demonstrated little, if any, identity of mRNA accumulation patterns. Similar variability was also seen for mRNAs which were also expressed in nonmuscle cells. Accumulation of mRNAs encoding .alpha.-skeletal, .alpha.-cardiac, .beta.- and .gamma.-actin, total myosin heavy chain, and .alpha.- and .beta.-tubulin also displayed discordant regulation, which has important implications for sarcomere assembly. Cardiac actin was the only muscle-specific transcript that was detected in low-confluency cells and was the major .alpha.-actin mRNA at all times in fusing cultures. Skeletal actin was transiently induced in fusing cultures and then reduced by an order of magnitude. Total myosin heavy-chain mRNA accumulation lagged behind that of .alpha.-actin. Whereas .beta.- and .gamma.-actin displayed a sharp decrease after initiation of fusion and thereafter did not change, .alpha.- and .beta.-tubulin were transiently induced to a high level during the time course in culture. We conclude that each gene may have its own unique determinants of transcript accumulation and that the phenotype of a muscle may not be determined so much by which genes are active or silent but rather by the extent to which their transcript levels are modulated. Finally, we observed that patterns of transcript accumulation established within the myotube cultures were consistent with the hypothesis and myoblasts isolated from adult tissue recapitulate a myogenic developmental program. However, we also detected a transient appearance of adult skeletal muscle-specific transcripts in high-confluence myoblast cultures. This indicates that the initial differentiation of these myoblasts may reflect a more complex process than simple recapitulation of development.