Premium
The Campylobacter jejuni dccRS two‐component system is required for optimal in vivo colonization but is dispensable for in vitro growth
Author(s) -
MacKichan Joanna K.,
Gaynor Erin C.,
Chang Christopher,
Cawthraw Shaun,
Newell Diane G.,
Miller Jeff F.,
Falkow Stanley
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04371.x
Subject(s) - biology , campylobacter jejuni , response regulator , mutant , gene , campylobacter , operon , virulence , colonization , microbiology and biotechnology , phenotype , genetics , bacteria
Summary A Campylobacter jejuni two‐component signal transduction system (TCSTS), designated dccR‐dccS ( d iminished c apacity to c olonize; Cj1223c‐Cj1222c), has been found to be important for in vivo colonization but dispensable for in vitro growth. A Δ dccR response regulator mutant generated using the virulent strain 81–176 background exhibited significantly reduced colonization of immunocompetent limited flora (I‐LF) mice, severe combined immunodeficient limited flora (SCID‐LF) mice, and 1‐day‐old chicks. A Δ dccS sensor kinase mutant was likewise defective for colonization in the I‐LF mouse model. Δ dccR ‐infected SCID‐LF mice also exhibited dramatically reduced inflammation relative to wild type‐infected SCID‐LF mice. Despite this diminished colonization capacity, the Δ dccRS mutants were indistinguishable from wild type for growth under numerous in vitro conditions as well as for various phenotypes. Microarray analysis identified several genes encoding putative periplasmic and membrane proteins as being regulated by this two‐component system; binding of purified His‐tagged DccR to the promoter region of two of these genes supports a direct protein–DNA interaction. A conserved repeat sequence was identified in the promoter regions of these genes and in three other promoter regions in the genome, including that of an operon encoding a putative type I secretion system. Two of the regulated target genes were found to be essential for optimal colonization. Both the two‐component system and the putative regulated genes have uncharacterized homologues in other Campylobacter and Helicobacter spp., suggesting that they may perform an important function in colonization among a variety of related pathogenic species.