Roy A, Haziza C, Danchin A
EMBO J. 1983;2(5):791-7. doi: 10.1002/j.1460-2075.1983.tb01502.x.
The regulatory region of the cya gene from Escherichia coli has been characterized by nucleotide sequence analysis and genetic approaches. Two promoters, P1 and P2, organized in that order with respect to the beginning of the cya open reading frame, were identified. Using cya-lac operon and protein fusions, it was possible to show that both promoters are active in vivo. P1 activity seemed sensitive to catabolite repression whereas activity of the stronger promoter, P2, did not respond to inhibition by glucose. No effect of cAMP or its receptor, catabolite activator protein (CAP), could be found although the DNA sequence reveals a consensus CAP site downstream of P2. The 548 nucleotides situated at the 3' end of the sequence carry an open reading frame which can tentatively be assigned to the beginning of adenylate cyclase. Among noteworthy features of the corresponding sequence are an UUG codon as the putative start site of cyclase, and a long hydrophobic stretch of amino acids resembling leader peptides in secreted or membrane proteins.
通过核苷酸序列分析和遗传学方法对大肠杆菌cya基因的调控区进行了表征。确定了两个启动子P1和P2，它们相对于cya开放阅读框的起始以该顺序排列。利用cya-乳糖操纵子和蛋白质融合，有可能证明这两个启动子在体内均具有活性。P1的活性似乎对分解代谢物阻遏敏感，而较强的启动子P2的活性则不受葡萄糖抑制的影响。尽管DNA序列显示在P2下游有一个共有CAP位点，但未发现cAMP或其受体分解代谢物激活蛋白（CAP）的作用。位于该序列3'端的548个核苷酸带有一个开放阅读框，可初步确定为腺苷酸环化酶的起始部分。相应序列的显著特征包括一个UUG密码子作为环化酶的假定起始位点，以及一段类似于分泌或膜蛋白中前导肽的长疏水氨基酸序列。
