title: Salmonella phage ST64B encodes a member of the SseK/NleB effector family.
abstract: Salmonella enterica is a species of bacteria that is a major cause of enteritis across the globe, while certain serovars cause typhoid, a more serious disease associated with a significant mortality rate. Type III secreted effectors are major contributors to the pathogenesis of Salmonella infections. Genes encoding effectors are acquired via horizontal gene transfer, and a subset are encoded within active phage lysogens. Because the acquisition of effectors is in flux, the complement of effectors possessed by various Salmonella strains frequently differs. By comparing the genome sequences of S. enterica serovar Typhimurium strain SL1344 with LT2, we identified a gene with significant similarity to SseK/NleB type III secreted effector proteins within a phage ST64B lysogen that is absent from LT2. We have named this gene sseK3. SseK3 was co-regulated with the SPI-2 type III secretion system in vitro and inside host cells, and was also injected into infected host cells. While no role for SseK3 in virulence could be identified, a role for the other family members in murine typhoid was found. SseK3 and other phage-encoded effectors were found to have a significant but sparse distribution in the available Salmonella genome sequences, indicating the potential for more uncharacterised effectors to be present in less studied serovars. These phage-encoded effectors may be principle subjects of contemporary selective processes shaping Salmonella-host interactions.
authors: Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia. nfbrown@unimelb.edu.au
authors: Nat F
authors: NF
authors: Brown
authors: Brian K
authors: BK
authors: Coombes
authors: Jenna L
authors: JL
authors: Bishop
authors: Mark E
authors: ME
authors: Wickham
authors: Michael J
authors: MJ
authors: Lowden
authors: Ohad
authors: O
authors: Gal-Mor
authors: David L
authors: DL
authors: Goode
authors: Erin C
authors: EC
authors: Boyle
authors: Kristy L
authors: KL
authors: Sanderson
authors: B Brett
authors: BB
authors: Finlay
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D005434:Flow Cytometry; D005814:Genes, Viral; D016679:Genome, Viral; D051379:Mice; D008969:Molecular Sequence Data; D021381:Protein Transport; D012475:Salmonella / Q000472:pathogenicity; D012483:Salmonella Phages / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; C490535:SseK1 protein, Salmonella enterica