title: Allelic exchange and site-directed mutagenesis probe the contribution of ActA amino-acid variability to phosphorylation and virulence-associated phenotypes among Listeria monocytogenes strains.
abstract: To test the hypothesis that actA allelic variation contributes to virulence differences among Listeria monocytogenes strains, cell-to-cell spread and intracellular ActA phosphorylation patterns were characterized for 14 wild-type isolates and selected isogenic mutants. Our data show that (i) while actA allelic variation is not responsible for enhanced cell-to-cell spread observed in epidemic clone I strains, actA allelic variation may contribute to reduced plaque size observed in some isolates, (ii) actA sequence alone determines phosphorylation-dependent ActA banding patterns, and (iii) sequence variation at the positively selected ActA residue 498 does not contribute to ActA phosphorylation patterns or to differences in cell-to-cell spread.
authors.affiliation: Department of Food Science, Cornell University, Ithaca, NY, USA. ajr29@cornell.edu
authors.forename: Angela J
authors.initials: AJ
authors.lastname: Roberts
authors.forename: Martin
authors.initials: M
authors.lastname: Wiedmann
mesh_terms: D000483:Alleles; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D014644:Genetic Variation; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D010766:Phosphorylation; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; C072980:actA protein, Listeria monocytogenes