Genetic and molecular analysis of GogB, a phage-encoded type III-secreted substrate in Salmonella enterica serovar typhimurium with autonomous expression from its associated phage.
Salmonella enterica serovar Typhimurium is lysogenized by several temperate bacteriophages that encode lysogenic conversion genes, which can act as virulence factors during infection and contribute to the genetic diversity and pathogenic potential of the lysogen. We have investigated the temperate bacteriophage called Gifsy-1 in S.enterica serovar Typhimurium and show here that the product of the gogB gene encoded within this phage shares similarity with proteins from other Gram-negative pathogens. The amino-terminal portion of GogB shares similarity with leucine-rich repeat-containing virulence-associated proteins from other Gram-negative pathogens, whereas the carboxyl-terminal portion of GogB shares similarity with uncharacterized proteins in other pathogens. We show that GogB is secreted by both type III secretion systems encoded in Salmonella Pathogenicity Island-1 (SPI-1) and SPI-2 but translocation into host cells is a SPI-2-mediated process. Once translocated, GogB localizes to the cytoplasm of infected host cells. The genetic regulation of gogB in Salmonella is influenced by the transcriptional activator, SsrB, under SPI-2-inducing conditions, but the modular nature of the gogB gene allows for autonomous expression and type III secretion following horizontal gene transfer into a heterologous pathogen. These data define the first autonomously expressed lysogenic conversion gene within Gifsy-1 that acts as a modular and promiscuous type III-secreted substrate of the infection process.
Coombes
Brian K
BK
Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
Wickham
Mark E
ME
Brown
Nat F
NF
Lemire
Sebastien
S
Bossi
Lionello
L
Hsiao
William W L
WW
Brinkman
Fiona S L
FS
Finlay
B Brett
BB
D000595:Amino Acid Sequence; D015967:Gene Expression Regulation, Viral; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D039002:Prophages / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D021381:Protein Transport; D012483:Salmonella Phages / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D012486:Salmonella typhimurium / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D016415:Sequence Alignment; D013379:Substrate Specificity; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D014764:Viral Proteins; D037521:Virulence Factors