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PMID: 8132466 Published · ppublish English Journal Article Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S.

The essential virulence protein VirB8 localizes to the inner membrane of Agrobacterium tumefaciens.

Journal of bacteriology ·Vol. 176 ·No. 6 ·1994-03-00 ·Pages 1711-7

Thorstenson YR, Zambryski PC

Abstract

Agrobacterium tumefaciens genetically transforms plant cells by transferring a specific DNA fragment from the bacterium through several biological membranes to the plant nucleus where the DNA is integrated. This complex DNA transport process likely involves membrane-localized proteins in both the plant and the bacterium. The 11 hydrophobic or membrane-localized proteins of the virB operon are excellent candidates to have a role in DNA export from agrobacteria. Here, we show by TnphoA mutagenesis and immunogold electron microscopy that one of the VirB proteins, VirB8, is located at the inner membrane. The observation that a virB8::TnphoA fusion restores export of alkaline phosphatase to the periplasm suggests that VirB8 spans the inner membrane. Immunogold labeling of VirB8 was detected on the inner membrane of vir-induced A. tumefaciens by transmission electron microscopy. Compared with that of the controls, VirB8 labeling was significantly greater on the inner membrane than on the other cell compartments. These results confirm the inner membrane localization of VirB8 and strengthen the hypothesis that VirB proteins help form a transfer DNA export channel or gate.

Related Genes
virB
MeSH Terms
Agrobacterium tumefaciens/chemistry,pathogenicity Amino Acid Sequence Bacterial Proteins/analysis DNA Transposable Elements Membrane Proteins/analysis Microscopy, Immunoelectron Molecular Sequence Data Mutagenesis Virulence Factors
Chemicals
Bacterial Proteins DNA Transposable Elements Membrane Proteins Virulence Factors
Authors & Affiliations
2 authors, click to expand affiliations / ORCID
Thorstenson Y R
Plant Biology Department, University of California, Berkeley 94720.
Zambryski P C
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Article Info
Journal
Journal of bacteriology
Abbr.
J Bacteriol
ISSN
0021-9193
DOI
10.1128/jb.176.6.1711-1717.1994
Published
1994-03-00
Pages
1711-7
Language
English
Region
United States
NLM ID
2985120R
PMCID
PMC205259
Subset
IM
Grants
NIGMS NIH HHS · GM07127 · United States
External Links
PubMed source DOI: 10.1128/jb.176.6.1711-1717.1994 PMC Full Text View journal details
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