Elmorjani K, Liotenberg S, Houmard J, de Marsac N T
Département de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France.
Biochem Biophys Res Commun. 1992 Dec 30;189(3):1296-302. doi: 10.1016/0006-291x(92)90214-6.
In order to study the regulation of the synthesis of glutamine synthetase in response to changes in environmental parameters (light and nitrogen sources), we have cloned and sequenced the glnA gene from the filamentous cyanobacterium Calothrix PCC 7601. This gene consists of 472 codons and encodes a polypeptide of M(r) 52,290 highly homologous to that from Anabaena PCC 7120, but more distant from those identified from other procaryotes. The relative abundance of the two glnA transcripts (1.6 and 1.8 kb) is equivalent in cells grown under either red or green light, but the 1.6-kb species predominates in nitrate-grown cells and the 1.8-kb species in ammonia-grown cells. The very high identity (74%) observed between the 374-bp long nucleotide sequence upstream from the Calothrix and Anabaena glnA genes suggests the existence of similar regulatory signals for the control of glnA expression in both cyanobacteria.
为了研究谷氨酰胺合成酶合成的调控对环境参数（光照和氮源）变化的响应，我们从丝状蓝细菌聚球藻PCC 7601中克隆并测序了glnA基因。该基因由472个密码子组成，编码一个分子量为52,290的多肽，与鱼腥藻PCC 7120的多肽高度同源，但与其他原核生物中鉴定出的多肽亲缘关系较远。在红光或绿光下生长的细胞中，两种glnA转录本（1.6 kb和1.8 kb）的相对丰度相当，但在硝酸盐培养的细胞中1.6 kb的转录本占主导，而在氨培养的细胞中1.8 kb的转录本占主导。聚球藻和鱼腥藻glnA基因上游374 bp长的核苷酸序列之间观察到的极高同源性（74%）表明，在这两种蓝细菌中存在类似的调控信号来控制glnA的表达。
