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HilD-mediated transcriptional cross-talk between SPI-1 and SPI-2.
Bustamante, Víctor H; Martínez, Luary C; Santana, Francisco J; Knodler, Leigh A; Steele-Mortimer, Olivia; Puente, José L.
Afiliação
  • Bustamante VH; Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa. Cuernavaca, Morelos 62210, Mexico.
Proc Natl Acad Sci U S A ; 105(38): 14591-6, 2008 Sep 23.
Article em En | MEDLINE | ID: mdl-18799744
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.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Salmonella typhimurium / Proteínas de Bactérias / Fatores de Transcrição / Proteínas de Membrana Idioma: En Revista: Proc Natl Acad Sci U S A Ano de publicação: 2008 Tipo de documento: Article País de afiliação: México País de publicação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Salmonella typhimurium / Proteínas de Bactérias / Fatores de Transcrição / Proteínas de Membrana Idioma: En Revista: Proc Natl Acad Sci U S A Ano de publicação: 2008 Tipo de documento: Article País de afiliação: México País de publicação: Estados Unidos