Putney S D, Herlihy W C, Schimmel P
Nature. 1983 Apr 21;302(5910):718-21. doi: 10.1038/302718a0.
Complete amino acid sequences have been established for 19 muscle-related proteins and these proteins are each sufficiently abundant to suggest that their mRNA levels are about 0.4% or higher. Based on these considerations, a simple theoretical analysis shows that clones for most of these proteins can be identified within a complementary DNA library by sequencing cDNA inserts from 150-200 randomly selected clones. This procedure should not only rigorously identify specific clones, but it could also uncover amino acid sequence variants of major muscle proteins such as the troponins. We have determined sequences for about 20,000 nucleotides within 178 randomly selected clones of a rabbit muscle cDNA library, and report here that in addition to finding sequences encoding the two known skeletal muscle isotypes of troponin C, we have discovered sequences encoding two forms of troponin T. Over the region of nucleotide sequence overlap in the troponin T clones, the new isotype diverges significantly from its counterpart. Altogether, clones for 13 of the 19 known muscle-specific proteins were identified, in addition to the clone for the new troponin T isotype.
已确定了19种肌肉相关蛋白的完整氨基酸序列，这些蛋白各自的丰度足以表明它们的mRNA水平约为0.4%或更高。基于这些考虑，一个简单的理论分析表明，通过对150 - 200个随机选择的克隆的cDNA插入片段进行测序，就可以在互补DNA文库中鉴定出这些蛋白中大多数的克隆。这个过程不仅应该能严格鉴定出特定的克隆，还可能揭示主要肌肉蛋白如肌钙蛋白的氨基酸序列变体。我们已经测定了兔肌肉cDNA文库中178个随机选择的克隆内约20,000个核苷酸的序列，并在此报告，除了发现编码两种已知骨骼肌肌钙蛋白C同型异构体的序列外，我们还发现了编码两种形式肌钙蛋白T的序列。在肌钙蛋白T克隆的核苷酸序列重叠区域，新的同型异构体与其对应物有显著差异。除了新的肌钙蛋白T同型异构体的克隆外，还鉴定出了19种已知肌肉特异性蛋白中13种的克隆。
