Two Additional Connections between the Transcriptional Programs Controlling Invasion and Intracellular Replication of Salmonella: HilD-SprB Positively Regulates phoP and slyA
Por:
Banda, Maria M., Perez-Morales, Deyanira, Zavala-Alvarado, Crispin, Nava-Galeana, Jessica, Bustamante, Victor H.
Publicada:
15 nov 2022
Ahead of Print:
1 oct 2022
Resumen:
Salmonella virulence relies on the ability of this bacterium to invade
the intestinal epithelium and to replicate inside macrophages, which are
functions mainly encoded in Salmonella pathogenicity islands 1 and 2
(SPI-1 and SPI-2), respectively. Complex regulatory programs control the
expression of SPI-1 and SPI-2 and functionally related genes, involving
the integration of ancestral regulators and regulators that Salmonella
has acquired during its evolution. Interestingly, some previous studies
have revealed cross talk between the regulatory programs for SPI-1 and
SPI-2. Here, we report two additional connections between the regulatory
programs controlling the expression of genes for invasion and
intracellular replication. Our results show that the acquired regulators
HilD and SprB, both encoded in SPI-1, induce, in a cascade fashion, the
expression of PhoP and SlyA, two ancestral regulators that activate the
expression of SPI-2 and other genes required for intracellular
replication. We provide evidence supporting that the regulation of phoP
and slyA by HilD-SprB was adapted during the divergence of Salmonella
from its closer species, Escherichia coli, with the acquisition of SPI-1
and thus the gain of HilD and SprB, as well as through cis-regulatory
evolution of phoP and slyA. Therefore, our study further expands the
knowledge about the intricate regulatory network controlling the
expression of virulence genes in Salmonella.
IMPORTANCE Bacteria have developed diverse regulatory mechanisms to
control genetic expression, in the case of pathogenic bacteria, to
induce the expression of virulence genes in particular niches during
host infection. In Salmonella, an intricate regulatory network has been
determined, which controls the spatiotemporal expression of the SPI-1
and SPI-2 gene clusters that mediate the invasion to and the replication
inside host cells, respectively. In this study, we report two additional
pathways of cross talk between the transcriptional programs for SPI-1
and SPI-2. Additionally, our results support that these additional
regulatory pathways were adapted during the divergence of Salmonella
from its closer species, Escherichia tali. This study further expands
the knowledge about the mechanisms determining the Salmonella virulence.
Filiaciones:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Microbiol Mol, Cuernavaca, Morelos, Mexico
|