The transcriptional regulation of the Streptococcus mutans bgl regulon
The transcriptional regulation of the Streptococcus mutans bgl regulon
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DOI：
10.1046/j.0902-0055.2001.00087.x
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发表时间：
2002-02-01
影响因子：
--
通讯作者：
Honeyman, AL
中科院分区：
文献类型：
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作者：
Cote, CK;Honeyman, AL
最近从变形链球菌中分离出的β-葡萄糖苷利用调节子已被证明含有参与β-葡萄糖苷水解的基因和推定的调节子。bglP基因编码磷酸烯醇化酸依赖性磷酸转移酶系统的β-葡糖苷特异性酶II（EII）组分，bglC基因编码推定的转录调节因子，bglA基因编码推定的磷酸-β-葡糖苷酶。为了研究这些基因的转录活性，将bglP、bglC和bglA基因的推定启动子区与E. colilacZ报告基因。将得到的报告质粒用于监测这些位点在S.变种人结果表明，这些基因在诱导性β-葡萄糖苷七叶苷存在下不被葡萄糖抑制至在不存在七叶苷的情况下观察到的表达水平。因此，这些基因座不受葡萄糖的分解代谢产物抑制至非诱导表达水平。bglC基因产物被确定为bglA基因的正转录调节因子，但不调节bglP基因的表达。因此，这些基因座的调节需要不同的和多种控制机制。
A beta-glucoside utilization regulon recently isolated from Streptococcus mutans has been shown to contain genes involved in beta-glucoside hydrolysis and a putative regulator. The bglP gene encodes a beta-glucoside-specific enzyme II (EII) component of the phosphoenolpyruvate-dependent phosphotransferase system, the bglC gene encodes a putative transcriptional regulator, and the bglA gene encodes a putative phospho-beta-glucosidase. To investigate the transcriptional activity of these genes, the putative promoter regions of the bglP, bglC and bglA genes were fused with the E. coli lacZ reporter gene. The resultant reporter plasmids were used to monitor the transcriptional activity of these loci in S. mutans. The results illustrate that these genes are not repressed by glucose in the presence of an inducing beta-glucoside, esculin, to the levels of expression observed in the absence of esculin. Therefore, these loci are not subject to catabolite repression by glucose to noninduced levels of expression. The bglC gene product was determined to be a positive transcriptional regulator of the bglA gene but does not regulate the expression of the bglP gene. Thus, regulation of these loci requires different and multiple control mechanisms.