Genomic analysis and growth-phase-dependent regulation of the SEF14 fimbriae of Salmonella enterica serovar Enteritidis.
Salmonella enterica serovar Enteritidis is a leading cause of food poisoning in the USA and Europe. Although Salmonella serovars share many fimbrial operons, a few fimbriae are limited to specific Samonella serovars. SEF14 fimbriae are restricted to group D Salmonella and the genes encoding this virulence factor were acquired relatively recently. Genomic, genetic and gene expression studies have been integrated to investigate the ancestry, regulation and expression of the sef genes. Genomic comparisons of the Salmonella serovars sequenced revealed that the sef operon is inserted in leuX in Salmonella Enteritidis, Salmonella Paratyphi and Salmonella Typhi, and revealed the presence of a previously unidentified 25 kb pathogenicity island in Salmonella Typhimurium at this location. Salmonella Enteritidis contains a region of homology between the Salmonella virulence plasmid and the chromosome downstream of the sef operon. The sef operon itself consists of four co-transcribed genes, sefABCD, and adjacent to sefD there is an AraC-like transcriptional activator that is required for expression of the sef genes. Expression of the sef genes was optimal during growth in late exponential phase and was repressed during stationary phase. The regulation was coordinated by the RpoS sigma factor.
Edwards
Robert A
RA
Department of Microbiology, University of Illinois, Urbana, IL 61801, USA1.
Matlock
Brian C
BC
Department of Microbiology, University of Illinois, Urbana, IL 61801, USA1.
Heffernan
Brian J
BJ
Department of Microbiology, University of Illinois, Urbana, IL 61801, USA1.
Maloy
Stanley R
SR
Department of Microbiology, University of Illinois, Urbana, IL 61801, USA1.
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D009876:Operon; D012478:Salmonella Food Poisoning / Q000382:microbiology; D012477:Salmonella enteritidis / Q000235:genetics* / Q000254:growth & development* / Q000472:pathogenicity / Q000648:ultrastructure; D012486:Salmonella typhimurium; D017422:Sequence Analysis, DNA; D015533:Transcriptional Activation; D014161:Transduction, Genetic; D014774:Virulence
D001426:Bacterial Proteins; C080931:sefA protein, Salmonella enteritidis; D036781:Fimbriae Proteins