In:
Journal of Bacteriology, American Society for Microbiology, Vol. 183, No. 11 ( 2001-06), p. 3310-3317
Abstract:
A yeast two-hybrid screen searching for chromosomally encoded proteins that interact with the Agrobacterium tumefaciens VirB8 protein was carried out. This screen identified an interaction candidate homologous to the partial sequence of a gene that had previously been identified in a transposon screen as a potential regulator of virG expression, chvD . In this report, the cloning of the entire chvD gene is described and the gene is sequenced and characterized. Insertion of a promoterless lacZ gene into the chvD locus greatly attenuated virulence and vir gene expression. Compared to that of the wild-type strain, growth of the chvD mutant was reduced in rich, but not minimal, medium. Expression of chvD , as monitored by expression of β-galactosidase activity from the chvD-lacZ fusion, occurred in both rich and minimal media as well as under conditions that induce virulence gene expression. The ChvD protein is highly homologous to a family of ATP-binding cassette transporters involved in antibiotic export from bacteria and has two complete Walker box motifs. Molecular genetic analysis demonstrated that disruption of either Walker A box, singly, does not inactivate this protein's effect on virulence but that mutations in both Walker A boxes renders it incapable of complementing a chvD mutant strain. Constitutive expression of virG in the chvD mutant strain restored virulence, supporting the hypothesis that ChvD controls virulence through effects on virG expression.
Type of Medium:
Online Resource
ISSN:
0021-9193
,
1098-5530
DOI:
10.1128/JB.183.11.3310-3317.2001
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2001
detail.hit.zdb_id:
1481988-0
SSG:
12
