INVESTIGADORES
FARIZANO Juan Vicente
congresos y reuniones científicas
Título:
Regulation of the acid-resistance asr gene by RcsCDB and RstBA systems in Salmonella Typhimurium
Autor/es:
MONICA F. TORREZ-LAMBERTI; JUAN V. FARIZANO; MÓNICA A. DELGADO; FABIAN LOPEZ
Lugar:
Rosario, Santa Fe
Reunión:
Congreso; L Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014
Institución organizadora:
SAIB
Resumen:
Salmonella Typhimurium uses specialized mechanisms to control the gene regulation, like the
two component systems, to survive at changes in the environmental. As the RcsCDB system is
induced in acidic medium, our goal was to identify genes whose expression depends on this
system activation. Our results showed that the RcsCDB system controls negatively the asr
transcription, an small acid shock RNA required to establish the Salmonella infection. As was
reported that the RstBA system upregulated the asr expression, we also investigated if exist an
RstBA/RcsCDB systems interaction to control this gene transcription, when the bacteria is growing
in acid medium. The bioinformatic and gel shift analysis showed that the asr gene promoter region
contains a potential binding site for RcsB and RstA, and that both regulators exert their effect by
directly binding to these boxes. In addition, using the asr::lacZY chromosomal transcriptional
fusions, we demonstrated that RcsB and RstA act independently to control the asr expression,
indicating that no interaction between these regulators occurs. However, more advanced studies
showed that the RcsB activation in an acid medium, represses expression of rstA. This observation
suggests that RcsB and RstA indirectly would interact to down or upregulate the asr transcription,
depending on the medium in which the bacteria is growing.