Affiliation:
1. Institut de Génétique et Microbiologie, Université Paris XI, 91405 Orsay, France
2. Institute of Molecular Biology, Dubravska cesta 21, 845 51 Bratislava, Slovak Republic
Abstract
ABSTRACT
The PhoR/PhoP two-component system of
Streptomyces lividans
was previously shown to allow the growth of the bacteria at low P
i
concentrations and to negatively control antibiotic production. The present study focuses on the transcriptional analysis of
phoR
and
phoP
, along with the
phoU
and
mtpA
genes that are transcribed divergently from the
phoRP
operon in
S. lividans
. The effect of
phoR
,
phoP
,
phoU
, and
ppk
mutations on transcription of these genes was examined under phosphate-replete and phosphate-limited conditions. We demonstrated that
phoR
and
phoP
were cotranscribed as a leaderless bicistronic transcript cleaved at discrete sites toward the 3′ end of
phoR
. In addition,
phoP
could also be transcribed alone from a promoter located at the 3′ end of
phoR
. The
phoU
and
mtpA
genes, predicted to encode metal binding proteins, were shown to be transcribed as monocistronic transcripts. The expression of
phoR-phoP
,
phoP
, and
phoU
was found to be induced under conditions of P
i
limitation in
S. lividans
TK24. This induction, requiring both PhoR and PhoP, was significantly weaker in the
phoU
mutant but much stronger in the
ppk
mutant than in the parental strain. The expression of
mtpA
was also shown to be up-regulated when P
i
was limiting but independently of PhoR/PhoP. The induction of
mtpA
expression was much stronger in the
phoU
mutant strain than in the other strains. This study revealed interesting regulatory interactions between the different genes and allowed us to propose putative roles for PhoU and MtpA in the adaptation to phosphate scarcity.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
64 articles.
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