CHARACTERIZATION OF PILIN GENES FROM 7 SEROLOGICALLY DEFINED PROTOTYPE STRAINS OF MORAXELLA-BOVIS

Numerous field isolates of Moraxella bovis have previously been classi fied by serological techniques into seven serogroups, each defined by homologous cross-reaction with antisera prepared against purified pill of a single prototype strain. The gene encoding pilin from each of th e prototype strains has been characterized by nucleotide sequence dete rmination. The coding sequences show extensive homology (70 to 80%),wh ile the proximal downstream sequences show a dichotomy into nonhomolog ous sets. The pilin genes of three more strains were also characterize d. The presence of an additional, partial pilin gene in each prototype strain was confirmed by Southern blot analysis, and the partial pilin genes from two strains of one serogroup were characterized by sequenc e determination. Features of the pilin gene sequences are considered i n relation to pilin gene inversion and the serological variants of str ains which may arise from gene inversion events.