Synthesis of myosin light chains and accumulation of translatable mRNA coding for light chain-like polypeptides in differentiating muscle cultures.
Synthesis of myosin light chains and accumulation of translatable mRNA coding for light chain-like polypeptides in differentiating muscle cultures.
复制标题
分化肌肉培养物中肌球蛋白轻链的合成和编码轻链样多肽的可翻译 mRNA 的积累。
DOI：
10.1111/j.1432-0436.1977.tb00929.x
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
D. Yaffe
中科院分区：
文献类型：
--
作者：
Z. Yablonka;D. Yaffe
大鼠骨骼肌肌球蛋白含有分子量分别为23,000,17,000和15,000的小亚基（轻链，这里指定为LC1， LC2, LC3）。在分化大鼠骨骼肌培养中，研究了分化过程中肌球蛋白轻链的合成和编码这些蛋白的mRNA的积累。当细胞融合前标记培养物时，凝胶电泳上与骨骼肌肌球蛋白轻链共迁移的放射性轻链不存在或仅几乎检测不到。从融合前培养中提取的与肌球蛋白重链相关的低分子量肽在骨骼肌肌球蛋白轻链上的电泳迁移率不同。细胞融合后，标记LC1和LC2的数量迅速增加。LC3的合成在细胞融合过程中几乎检测不到，从未超过LC1和LC2合成量的五分之一。在分化过程中不同时间提取的聚腺苷化RNA在小麦无生殖细胞系统中被翻译。用等电聚焦- sds双向凝胶电泳对产物进行分析，并测定多肽与肌球蛋白轻链共迁移的放射性。在细胞融合前几小时提取的RNA制剂的产物中，可以检测到与LC1和LC2共迁移的少量放射性产物。然而，由融合后RNA引导的无细胞系统合成了大量的LC1和LC2样多肽。LC1和LC2可翻译mRNA的快速积累与细胞融合密切相关。与LC3共迁移的放射性多肽在融合前RNA的引导下在无细胞体系中大量合成，融合后提取的RNA仅适度增加。
Rat skeletal muscle myosin contains small subunits (light chains, here designated LC1, LC2, LC3) of molecular weight 23,000, 17,000 and 15,000, respectively. The synthesis of myosin light chains during differentiation and the accumulation of mRNA which codes for these proteins were investigated in differentiating rat skeletal muscle cultures. When cultures were labeled prior to cell fusion, radioactive light chains which co-migrated with skeletal muscle myosin light chains on gel electrophoresis were absent or only barely detectable. The low molecular weight peptides which were associated with the heavy chain of myosin extracted from pre-fusion cultures differed in their electrophoretic mobility from light chains of skeletal muscle myosin. Following cell fusion, the amount of labeled LC1 and LC2 increased rapidly. The synthesis of LC3 was barely detectable during cell fusion and never exceeded one-fifth of the amounts of LC1 and LC2 synthesized. Polyadenylated RNA extracted at different times during differentiation was translated in the wheat germ cell-free system. The products were analyzed on isoelectnc focusing-SDS two-dimensional gel electrophoresis, and the radioactivity of the polypeptides co-migrating with myosin light chains was measured. Small amounts of radioactive products co-migrating with LC1 and LC2 became detectable among products of RNA preparations extracted several hours prior to cell fusion. However, the cell-free system directed by post-fusion RNA synthesized much larger amounts of LC1- and LC2- like polypeptides. Rapid accumulation of translatable mRNA for LC1 and LC2 was closely correlated with cell fusion. Radioactive polypeptides co-migrating with LC3 were synthesized in significant amounts in a cell-free system directed by pre-fusion RNA and increased only moderately when RNA extracted after fusion was used.