Luesink E J, Marugg J D, Kuipers O P, de Vos W M
Microbial Ingredients Section, NIZO Food Research, 6710 BA Ede, The Netherlands.
J Bacteriol. 1999 Mar;181(6):1924-6. doi: 10.1128/JB.181.6.1924-1926.1999.
The divergently transcribed sacBK and sacAR operons, which are involved in the utilization of sucrose by Lactococcus lactis NZ9800, were examined by transcriptional and gene inactivation studies. Northern analyses of RNA isolated from cells grown at the expense of different carbon sources revealed three sucrose-inducible transcripts: one of 3.2 kb containing sacB and sacK, a second of 3.4 kb containing sacA and sacR, and a third of 1.8 kb containing only sacR. The inactivation of the sacR gene by replacement recombination resulted in the constitutive transcription of the sacBK and sacAR operons in the presence of different carbon sources, indicating that SacR acts as a repressor of transcription.
通过转录和基因失活研究,对参与乳酸乳球菌NZ9800利用蔗糖的反向转录sacBK和sacAR操纵子进行了检测。对以不同碳源为代价生长的细胞中分离出的RNA进行Northern分析,发现了三种蔗糖诱导转录本:一种3.2 kb,包含sacB和sacK;第二种3.4 kb,包含sacA和sacR;第三种1.8 kb,仅包含sacR。通过置换重组使sacR基因失活,导致在不同碳源存在下sacBK和sacAR操纵子组成型转录,表明SacR作为转录阻遏物发挥作用。