PMID:22287513

Citation	Boutry, C, Wahl, A, Delplace, B, Clippe, A, Fontaine, L and Hols, P (2012) Adaptor protein MecA is a negative regulator of the expression of late competence genes in Streptococcus thermophilus. J. Bacteriol. 194:1777-88
Abstract	In Streptococcus thermophilus, the ComRS regulatory system governs the transcriptional level of comX expression and, hence, controls the early stage of competence development. The present work focuses on the posttranslational control of the activity of the sigma factor ComX and, therefore, on the late stage of competence regulation. In silico analysis performed on the S. thermophilus genome revealed the presence of a homolog of mecA (mecA(St)), which codes for the adaptor protein that is involved in ComK degradation by ClpCP in Bacillus subtilis. Using reporter strains and microarray experiments, we showed that MecA(St) represses late competence genes without affecting the early competence stage under conditions that are not permissive for competence development. In addition, this repression mechanism was found not only to act downstream of comX expression but also to be fully dependent on the presence of a functional comX gene. This negative control was similarly released in strains deleted for clpC, mecA, and clpC-mecA. Under artificial conditions of comX expression, we next showed that the abundance of ComX is higher in the absence of MecA or ClpC. Finally, results of bacterial two-hybrid assays strongly suggested that MecA interacts with both ComX and ClpC. Based on these results, we proposed that ClpC and MecA act together in the same regulatory circuit to control the abundance of ComX in S. thermophilus.
Links	PubMed PMC3302459 Online version:10.1128/JB.06800-11
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Gene Expression Regulation, Bacterial; Repressor Proteins/genetics; Repressor Proteins/metabolism; Streptococcus thermophilus/genetics; Streptococcus thermophilus/metabolism; Transformation, Bacterial
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STRT2:MECA	involved_in	GO:0045892: negative regulation of transcription, DNA-templated	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
STRT2:MECA		GO:0045892: negative regulation of transcription, DNA-templated	ECO:0000315:		P		Figure 4: These data show that MecA and ClpC, but not ClpE, negatively affect the abundance of ComX in vivo in S. thermophilus LMD-9, confirming the above-described expression results obtained with the reporter strains.	complete CACAO 9991

References

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