REGULATION OF TRANSCRIPTION BY CYCLIC AMP-DEPENDENT PROTEIN-KINASE
REGULATION OF TRANSCRIPTION BY CYCLIC AMP-DEPENDENT PROTEIN-KINASE
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DOI：
10.1073/pnas.86.13.4887
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发表时间：
1989-07-01
影响因子：
11.1
通讯作者：
MCKNIGHT, GS
中科院分区：
文献类型：
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作者：
MELLON, PL;CLEGG, CH;MCKNIGHT, GS
CAMP依赖的蛋白激酶(PKA；ATP：蛋白磷酸转移酶；EC 2.7.1.37)似乎是哺乳动物细胞内cAMP反应的主要介质。我们通过将野生型或突变型PKA亚基与cAMP可诱导的报告基因共转染，研究了PKA亚基在调控cAMP反应的特定基因中的作用。在cAMP水平没有升高的情况下，催化亚基的过表达诱导了三个cAMP调节的启动子(α-亚基、c-fos、E1a)的表达，但不影响两个非调控启动子的表达(劳斯肉瘤病毒、猿猴病毒40)。共转染包含两个cAMP结合位点突变的调节亚基基因，强烈抑制cAMP反应的α亚基启动子的基础和诱导表达，而不影响劳斯肉瘤病毒启动子的表达。这些实验表明，cAMP通过催化亚基的磷酸化诱导基因表达，并且磷酸化的环境程度决定了cAMP调节的α亚基基因的基础水平和诱导表达。
cAMP-dependent protein kinase (PKA;ATP:protein phosphotransferase; EC 2.7.1.37) appears to be the major mediator of cAMP responses in mammalian cells. We have investigated the role of PKA subunits in the regulation of specific genes in response to cAMP by cotransfection of wild-type or mutant subunits of PKA together with cAMP-inducible reporter genes. Overexpression of catalytic subunit induced expression from three cAMP-regulated promoters (.alpha.-subunit, c-fos, E1A) in the absence of elevated levels of cAMP but did not affect expression from two unregulated promoters (Rous sarcoma virus, simian virus 40). Cotransfection of a regulatory subunit gene containing mutations in both cAMP binding sites strongly repressed both basal and induced expression from the cAMP-responsive .alpha.-subunit promoter without affecting expression from the Rous sarcoma virus promoter. These experiments indicate that cAMP induces gene expression through phosphorylation by the catalytic subunit and that the ambient degree of phosphorylation dictates the level of basal as well as induced expression of the cAMP-regulated .alpha.-subunit gene.