INVESTIGADORES
ESPARIZ Martin
artículos
Título:
Expression of the agmatine deiminase pathway in Enterococcus faecalis is activated by the AguR regulator and repressed by CcpA and PTSMan systems
Autor/es:
CRISTIAN SUAREZ; MARTÍN ESPARIZ; VÍCTOR S. BLANCATO; CHRISTIAN MAGNI
Revista:
PLOS ONE
Editorial:
PUBLIC LIBRARY SCIENCE
Referencias:
Lugar: San Francisco; Año: 2013 vol. 8 p. 1 - 11
ISSN:
1932-6203
Resumen:
Although the agmatine deiminase system
(AgDI) has been investigated in Enterococcus faecalis, little
information is available with respect to its gene regulation. In this study we
demonstrate that the presence of exogenous agmatine induces the expression of agu
genes in this bacterium. In contrast to the homologous and extensively characterized AgDI system of S. mutants, the
aguBDAC operon in E. faecalis is not induced in response
to low pH. In spite of this, agmatine catabolism in this bacterium contributes
by neutralizing the external medium while enhancing bacterial growth.
Our results indicate that carbon catabolic
repression (CCR) operates on the AgDI system via a mechanism that involves
interaction of CcpA and P-Ser-HPr with a cre
site found in an unusual position considering the aguB promoter (55 nt upstream the +1 position). In addition, we
found that components of the mannose phosphotransferase (PTSMan)
system also contributed to CCR in E.
faecalis since a complete relief of the PTS-sugars repressive effect was
observed only in a PTSMan and CcpA double defective strain.
Our gene context analysis revealed that aguR is present in oral and
gastrointestinal microorganisms. Thus, regulation of the aguBDAC operon in E. faecalis
seems to have evolved to obtain energy and resist low pH conditions in order to
persist and colonize gastrointestinal niches.