In:
Microbiology, Microbiology Society, Vol. 152, No. 2 ( 2006-02-01), p. 323-331
Abstract:
Natural competence for genetic transformation in Streptococcus pneumoniae is controlled by the ComCDE signal-transduction pathway. Together, ComD, a membrane histidine kinase, and ComE, its cognate response regulator, constitute a typical two-component regulatory system involved in sensing the comC -encoded competence-stimulating peptide (CSP). The comCDE operon is strongly upregulated when CSP reaches a critical threshold, probably to coordinate competence induction throughout the population. During a study of the early regulation of the comCDE operon, a mutation which resulted in increased β -galactosidase production from a comC : : lacZ fusion was isolated. This mutation, which was characterized as a G→T change in the transcription terminator of the tRNA Arg located immediately upstream of comCDE , is suggested to destabilize the terminator and to allow transcriptional readthrough of comCDE . Here, it is shown that, quite unexpectedly, the mutation confers reduced transformability. A series of experiments undertaken with the aim of understanding this surprising phenotype is described. Evidence is presented that increased basal-level expression of comDE impedes both spontaneous and CSP-induced competence in S. pneumoniae . There is a discussion of how an increased concentration of ComD and/or ComE could affect competence development.
Type of Medium:
Online Resource
ISSN:
1350-0872
,
1465-2080
DOI:
10.1099/mic.0.28425-0
Language:
English
Publisher:
Microbiology Society
Publication Date:
2006
detail.hit.zdb_id:
2008736-6
SSG:
12
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