Structural Characterization of the virB Operon of the Hairy-root-inducing Plasmid pRiA4 (MOLECULAR BIOLOGY AND INFORMATION-Molecular Biology)

Abstract

The virulence (vir) loci of the hairy-root-inducing plasmid pRiA4 are essential for pathogenicity of its host Agrobacterium rhizogenes A4. We have now determined the nucleotide sequence of virB region (9, 926 bp). It was found that the virB operon is composed of 11 genes (virB1 to virB11), whose products mostly appear to be associated with the cell membrane. A novel structural characteristic is frequent overlapping between the translation termination and initiation codons of the adjacent genes This is indicative of fine tuning of relative translation frequencies for each VirB protein, supporting the view that VirB multisubunit complexes provide facilities for T-DNA transfer at the bacterial cell membrane.