Identification of a native Dichelobacter nodosus plasmid and implications for the evolution of the vap regions.

Department of Microbiology, Monash University, Clayton, Victoria, Australia.
Gene (Impact Factor: 2.2). 07/1996; 172(1):111-6. DOI: 10.1016/0378-1119(96)00032-7
Source: PubMed

ABSTRACT Studies on the role of various virulence factors of the ovine pathogen, Dichelobacter nodosus, have suffered from the absence of a mechanism for the introduction of DNA into this organism. As an initial step in the development of genetic methods, we have identified and cloned a native 10-kb plasmid, pJIR896, from a clinical isolate. This plasmid was found to be a circular form of vap region 1/3 that is found in the reference strain, A198. However, pJIR896 lacked the duplicated region present in the A198 sequence and instead contained a 1.7-kb putative insertion sequence, IS1253, which shared similarity to a number of unusual IS elements. A model is proposed for the evolution of vap region 1/3 which involves the integration of a plasmid, such as pJIR896, and subsequent rearrangements resulting from the deletion or transposition of IS1253.

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