A deletion in the sapA homologue cluster is responsible for the loss of the S-layer in Campylobacter fetus strain TK

作者：Fujita M; Moriya T; Fujimoto S; Hara N; Amako K

来源：Archives of Microbiology, 1997, 167(4): 196-201.

DOI：10.1007/s002030050435

• Campylobacter fetus
• sapA homologues
• promoter
• chi sequence
• antigenic variation
• surface layer

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(-)).

• 出版日期1997-4