title: Flagellin gene sequence evolution in Salmonella.
abstract: Salmonella exhibits 70 serologically distinct flagellins, used internationally to diagnose and track infections. The terminal sequences of flagellin protein subunits are conserved in a range of bacteria and are here used as evolutionary markers to reveal how new serotypes arise. Terminal sequences of flagellins that exhibit factors g or m (G-group) were distinct from other Salmonella antigens (Non-G-group) and cluster more closely with Escherichia coli. It is postulated that G-group flagellins were inherited from a common ancestor of E. coli and Salmonella and that these antigens were among the original set in Salmonella. Sequence differences at the 5' termini may prevent recombination between co-infecting strains. Evidence of increased variation of flagellin in rare biphasic G-group serotypes suggests that the presence of a second flagellin locus allows mutation of the G-group flagellin. FljB probably arose from a single duplication of a Non-G gene, since which synonymous mutations resulted in the fljB-specific sequence at the 5' termini.
authors.affiliation: Centre for Infections, Health Protection Agency, 61 Colindale Avenue, Colindale, London NW9 5EQ, UK. chloe.mortimer@hpa.org.uk
authors.forename: Chloe K B
authors.initials: CK
authors.lastname: Mortimer
authors.forename: Saheer E
authors.initials: SE
authors.lastname: Gharbia
authors.forename: Julie M J
authors.initials: JM
authors.lastname: Logan
authors.forename: Tansy M
authors.initials: TM
authors.lastname: Peters
authors.forename: Catherine
authors.initials: C
authors.lastname: Arnold
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D019143:Evolution, Molecular; D005408:Flagellin / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012475:Salmonella / Q000145:classification / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000942:Antigens, Bacterial; D005408:Flagellin