title: A deletion in the sapA homologue cluster is responsible for the loss of the S-layer in Campylobacter fetus strain TK.
abstract: The surface array protein (SAP) of Campylobacter fetus strain TK is encoded by seven homologous sapA genes clustered on the chromosomal DNA. The spontaneously arising variant strain TK(SAP-) produces no SAP and carries an approximately 10-kb chromosomal deletion. To elucidate the mechanism underlying the loss of SAP synthesis, we analyzed the region containing the sapA homologues and the deletion. We constructed a physical map of the sapA cluster region by aligning the clones that contain sapA homologues. These analyses demonstrated that all sapA homologues were located within a limited region of about 50 kb of chromosomal DNA of strain TK. The TK(SAP-) deletion was located within this cluster and was 13.3 kb in size. The deletion occurred between two sapA homologues and resulted in the formation of a chimeric sapA homologue in the variant strain. Sequence analysis of the upstream regions and the conserved regions of all sapA homologues revealed a high degree of similarity. However, only one sapA homologue contained a putative promoter sequence. This promoter sequence was located in the deleted region. Thus, the deletion of the promoter appears to be responsible for the loss of SAP expression in TK(SAP-).
authors.affiliation: Department of Bacteriology, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-82, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Fujita
authors.forename: T
authors.initials: T
authors.lastname: Moriya
authors.forename: S
authors.initials: S
authors.lastname: Fujimoto
authors.forename: N
authors.initials: N
authors.lastname: Hara
authors.forename: K
authors.initials: K
authors.lastname: Amako
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins; D001483:Base Sequence; D002168:Campylobacter fetus / Q000235:genetics*; D017353:Gene Deletion; D005798:Genes, Bacterial; D008562:Membrane Glycoproteins; D008969:Molecular Sequence Data; D005810:Multigene Family; D011401:Promoter Regions, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins