Regulation of the Competence Pathway as a Novel Role Associated with a Streptococcal Bacteriocin
Regulation of the Competence Pathway as a Novel Role Associated with a Streptococcal Bacteriocin
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DOI：
10.1128/jb.05968-11
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发表时间：
2011-12-01
影响因子：
3.2
通讯作者：
Levesque, Celine M.
中科院分区：
文献类型：
--
作者：
Dufour, Delphine;Cordova, Martha;Levesque, Celine M.
口腔生物膜生物变形链球菌必须面对大量的环境压力才能在其自然栖息地生存。在特定的胁迫下，变形链球菌表达能力刺激肽(CSP)信息素，已知能诱导自溶并促进外源DNA的吸收和掺入，这一过程被称为DNA转化。我们先前已经证明，CSP诱导的CipB细菌素(Mutalin V)是参与这两个细胞过程的主要因素。我们在这项工作中的目的是表征CipB细菌素在DNA转化中的作用。虽然其他细菌素突变体在CSP诱导的条件下获得DNA的能力受到损害，但Delta cipB突变体是唯一一个转化效率急剧下降的突变体。CipB细菌素的自溶功能不参与DNA转化过程，因为通过裂解细胞亚群释放的因子不有助于存活群体中遗传能力的发展。此外，CipB似乎不参与帮助DNA通过的膜去极化。基于基因芯片的表达谱分析表明，在CSP诱导条件下，CipB共调控了130个基因，其中包括comDE基因、comR和comX基因，编码了影响变形链球菌能力发展的关键因子。我们还发现，对CipB诱导的自溶具有免疫力的CipI蛋白也阻止了CipB的转录调节活性。我们的数据表明，变形链球菌CipB细菌素除了在细胞裂解中发挥作用外，还作为一种多肽调节因子来调控能力调节子的转录。
The oral biofilm organism Streptococcus mutans must face numerous environmental stresses to survive in its natural habitat. Under specific stresses, S. mutans expresses the competence-stimulating peptide (CSP) pheromone known to induce autolysis and facilitate the uptake and incorporation of exogenous DNA, a process called DNA transformation. We have previously demonstrated that the CSP-induced CipB bacteriocin (mutacin V) is a major factor involved in both cellular processes. Our objective in this work was to characterize the role of CipB bacteriocin during DNA transformation. Although other bacteriocin mutants were impaired in their ability to acquire DNA under CSP-induced conditions, the Delta cipB mutant was the only mutant showing a sharp decrease in transformation efficiency. The autolysis function of CipB bacteriocin does not participate in the DNA transformation process, as factors released via lysis of a subpopulation of cells did not contribute to the development of genetic competence in the surviving population. Moreover, CipB does not seem to participate in membrane depolarization to assist passage of DNA. Microarray-based expression profiling showed that under CSP-induced conditions, CipB regulated similar to 130 genes, among which are the comDE locus and comR and comX genes, encoding critical factors that influence competency development in S. mutans. We also discovered that the CipI protein conferring immunity to CipB-induced autolysis also prevented the transcriptional regulatory activity of CipB. Our data suggest that besides its role in cell lysis, the S. mutans CipB bacteriocin also functions as a peptide regulator for the transcriptional control of the competence regulon.