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HilD-mediated transcriptional cross-talk between SPI-1 and SPI-2.
Proc Natl Acad Sci U S A. 2008 Sep 23; 105(38):14591-6.PN

Abstract

The acquisition of new genetic traits by horizontal gene transfer and their incorporation into preexisting regulatory networks have been essential events in the evolution of bacterial pathogens. An example of successful assimilation of virulence traits is Salmonella enterica, which acquired, at distinct evolutionary times, Salmonella pathogenicity island 1 (SPI-1), required for efficient invasion of the intestinal epithelium and intestinal disease, and SPI-2, essential for Salmonella replication and survival within macrophages and the progression of a systemic infection. A positive regulatory cascade mainly composed of HilD, HilA, and InvF, encoded in SPI-1, controls the expression of SPI-1 genes, whereas the two-component regulatory system SsrA/B, encoded in SPI-2, controls expression of SPI-2 genes. In this study, we report a previously undescribed transcriptional cross-talk between SPI-1 and SPI-2, where the SPI-1-encoded regulator HilD is essential for the activation of both the SPI-1 and SPI-2 regulons but at different times during the stationary phase of growth in Luria-Bertani medium. Our data indicate that HilD counteracts the H-NS-mediated repression exerted on the OmpR-dependent activation of the ssrAB operon by specifically interacting with its regulatory region. In contrast, HilD is not required for SPI-2 regulon expression under the in vitro growth conditions that are thought to resemble the intracellular environment. Our results suggest that two independent SPI-2 activation pathways evolved to take advantage of the SPI-2-encoded information at different niches and, in consequence, in response to different growth conditions.

Authors+Show Affiliations

Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa. Cuernavaca, Morelos 62210, Mexico.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Intramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18799744

Citation

Bustamante, Víctor H., et al. "HilD-mediated Transcriptional Cross-talk Between SPI-1 and SPI-2." Proceedings of the National Academy of Sciences of the United States of America, vol. 105, no. 38, 2008, pp. 14591-6.
Bustamante VH, Martínez LC, Santana FJ, et al. HilD-mediated transcriptional cross-talk between SPI-1 and SPI-2. Proc Natl Acad Sci U S A. 2008;105(38):14591-6.
Bustamante, V. H., Martínez, L. C., Santana, F. J., Knodler, L. A., Steele-Mortimer, O., & Puente, J. L. (2008). HilD-mediated transcriptional cross-talk between SPI-1 and SPI-2. Proceedings of the National Academy of Sciences of the United States of America, 105(38), 14591-6. https://doi.org/10.1073/pnas.0801205105
Bustamante VH, et al. HilD-mediated Transcriptional Cross-talk Between SPI-1 and SPI-2. Proc Natl Acad Sci U S A. 2008 Sep 23;105(38):14591-6. PubMed PMID: 18799744.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - HilD-mediated transcriptional cross-talk between SPI-1 and SPI-2. AU - Bustamante,Víctor H, AU - Martínez,Luary C, AU - Santana,Francisco J, AU - Knodler,Leigh A, AU - Steele-Mortimer,Olivia, AU - Puente,José L, Y1 - 2008/09/17/ PY - 2008/9/19/pubmed PY - 2008/10/23/medline PY - 2008/9/19/entrez SP - 14591 EP - 6 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc Natl Acad Sci U S A VL - 105 IS - 38 N2 - The acquisition of new genetic traits by horizontal gene transfer and their incorporation into preexisting regulatory networks have been essential events in the evolution of bacterial pathogens. An example of successful assimilation of virulence traits is Salmonella enterica, which acquired, at distinct evolutionary times, Salmonella pathogenicity island 1 (SPI-1), required for efficient invasion of the intestinal epithelium and intestinal disease, and SPI-2, essential for Salmonella replication and survival within macrophages and the progression of a systemic infection. A positive regulatory cascade mainly composed of HilD, HilA, and InvF, encoded in SPI-1, controls the expression of SPI-1 genes, whereas the two-component regulatory system SsrA/B, encoded in SPI-2, controls expression of SPI-2 genes. In this study, we report a previously undescribed transcriptional cross-talk between SPI-1 and SPI-2, where the SPI-1-encoded regulator HilD is essential for the activation of both the SPI-1 and SPI-2 regulons but at different times during the stationary phase of growth in Luria-Bertani medium. Our data indicate that HilD counteracts the H-NS-mediated repression exerted on the OmpR-dependent activation of the ssrAB operon by specifically interacting with its regulatory region. In contrast, HilD is not required for SPI-2 regulon expression under the in vitro growth conditions that are thought to resemble the intracellular environment. Our results suggest that two independent SPI-2 activation pathways evolved to take advantage of the SPI-2-encoded information at different niches and, in consequence, in response to different growth conditions. SN - 1091-6490 UR - https://www.unboundmedicine.com/medline/citation/18799744/HilD_mediated_transcriptional_cross_talk_between_SPI_1_and_SPI_2_ L2 - http://www.pnas.org/cgi/pmidlookup?view=long&pmid=18799744 DB - PRIME DP - Unbound Medicine ER -