The sigA gene encoding the major sigma factor of RNA polymerase from the marine cyanobacterium Synechococcus sp strain PCC 7002: Cloning and characterization
The sigA gene encoding the major sigma factor of RNA polymerase from the marine cyanobacterium Synechococcus sp strain PCC 7002: Cloning and characterization
复制标题
DOI：
10.1099/13500872-142-2-347
复制
发表时间：
1996-02-01
期刊：
影响因子：
2.8
通讯作者：
Bryant, DA
中科院分区：
文献类型：
--
作者：
Caslake, LF;Bryant, DA
从聚珠球菌（Synechococcus sp.）菌株pcc7002中分离并鉴定了主sigma因子的编码基因。聚球菌菌株pcc7002 sigA基因编码375个氨基酸（43.7 kDa）的蛋白质，这是正常生长条件下生存所必需的。SigA蛋白在大肠杆菌中大量产生，纯化后的蛋白用于家兔多克隆抗血清的培养。用该抗血清对聚血球菌PR6000部分纯化的RNA聚合酶进行免疫印迹分析，通过对大肠杆菌中过量产生的SigA蛋白的氨基酸测序结果与蓝藻中RNA聚合酶粗制剂中SigA蛋白的免疫印迹分析，确定了可能的体内翻译起始位点。sigA基因编码在1700个碱基的转录本上，从可能的体内翻译起始位点上游启动496个核苷酸。从生长培养基中去除组合氮后，sigA转录本的丰度迅速下降。
The gene encoding the principal sigma factor from Synechococcus sp. strain PCC 7002 was isolated and characterized. The Synechococcus sp, strain PCC 7002 sigA gene encodes a protein of 375 amino acids (43.7 kDa) that is required for viability under normal growth conditions. The SigA protein was overproduced in Escherichia coli and the purified protein was used to raise polyclonal antiserum in rabbits. This antiserum was used in immunoblot analyses of partially purified RNA polymerase from Synechococcus sp, strain PR6000, The probable in vivo translational start site was identified by a comparison of amino acid sequencing results obtained with SigA proteins overproduced in E. coli with immunoblot analyses of SigA protein in crude preparations of RNA polymerase from the cyanobacterium. The sigA gene is encoded on a transcript of 1700 bases that initiates 496 nucleotides upstream from the probable in vivo translational start site. The abundance of sigA transcripts decreases rapidly after the removal of combined nitrogen from the growth medium.