Robishaw J D, Smigel M D, Gilman A G
J Biol Chem. 1986 Jul 25;261(21):9587-90.
Most cells contain two forms of the alpha subunit of the G protein (Gs) that stimulates adenylate cyclase; their apparent molecular weights are 45,000 and 52,000. Two cDNAs that correspond to distinct mRNAs for the alpha subunit of Gs have been cloned from a bovine adrenal library and sequenced. The sequences of the two cDNAs, designated pGs-l and pGs-S, are identical except for a single stretch of 46 nucleotides in the coding region, where four are altered and 42 are deleted in pGs-S. Expression of pGs-S and pGs-l in COS-m6 cells yields protein products with apparent molecular weights of 45,000 and 52,000, respectively, based on their mobility in sodium dodecyl sulfate-polyacrylamide gels. We conclude that pGs-S and pGs-l encode the 45- and 52-kDa forms of Gs alpha, respectively, and propose that the mRNAs encoding these proteins arise from a single gene by internal alternative RNA splicing.
大多数细胞含有两种刺激腺苷酸环化酶的G蛋白（Gs）α亚基形式；它们的表观分子量分别为45,000和52,000。已从牛肾上腺文库中克隆并测序了两个与Gsα亚基不同mRNA相对应的cDNA。这两个cDNA，分别命名为pGs-1和pGs-S，其序列除了编码区域中有一段46个核苷酸的序列外完全相同，在该区域中，pGs-S有4个核苷酸发生改变且42个核苷酸被删除。根据pGs-S和pGs-1在十二烷基硫酸钠-聚丙烯酰胺凝胶中的迁移率，它们在COS-m6细胞中的表达分别产生表观分子量为45,000和52,000的蛋白质产物。我们得出结论，pGs-S和pGs-1分别编码45 kDa和52 kDa形式的Gsα，并提出编码这些蛋白质的mRNA是通过内部选择性RNA剪接从单个基因产生的。
