|Thompson, M - IOWA STATE UNIVERSITY|
Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: May 24, 2001
Publication Date: N/A
Technical Abstract: B. hyodysenteriae (B. hyo.), the etiologic agent of swine dysentery, contains a mitomycin C-inducible prophage, VSH-1. VSH-1 particles are non-lytic, package random 7.5 kb fragments of the host chromosome, and serve as generalized transducing bacteriophages for B. hyo. After SDS-PAGE, purified whole virion particles separated into 14 protein bands ranging in molecular mass from 12 to 101 kD. Unambiguous amino terminal sequences were determined for proteins designated V1, Svp101, Svp53, Svp45, Svp32, Svp19, V7, Svp13, Svp38, Svp24, V10. PCR primers and nucleotide probes designed from the protein sequences were used to amplify, detect, sequence, and map corresponding VSH-1 genes in purified or cloned B. hyo. chromosomal DNA. Genes encoding nine of the virion-associated proteins spanned 12.4 kb of chromosomal DNA. The genes were contained within 16.2 kb of DNA delimited by predicted ORFs transcribed in the opposite direction and encoding putative bacterial proteins. Thus only VSH-1 structural protein genes were detected and assigned to a DNA region substantially larger than the 7.5 kb DNA contained in virion heads. To evaluate VSH-1's ability to self-replicate, quantitative PCR analysis was used to compare copy numbers of VSH-1 genes (for Svp38 and Svp53) with those of B. hyo. genes (for Nox and E/D transporter proteins). VSH-1 genes were not present in greater copy number than B. hyo. genes in either VSH-1 virions or in B. hyo. cells treated with mitomycin C. The nature of the VSH-1 genome, the size of the genome, and our inability to detect increases in copy number of VSH-1 genes suggest phage VSH-1 is defective in self-replication.