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VirA and VirG activate the Ti plasmid repABC operon, elevating plasmid copy number in response to wound-released chemical signals.
Proc Natl Acad Sci U S A. 2005 Oct 11; 102(41):14843-8.PN

Abstract

The vir genes of Agrobacterium tumefaciens tumor-inducing (Ti) plasmids direct the transfer of oncogenic portion of the Ti (tumor-inducing) plasmid that is transferred to plant cells (T-DNA) into plant cells and are coordinately induced by plant-released phenolic chemical signals. We have used DNA microarrays, representing all genes of the octopine- and nopaline-type Ti plasmids, to identify all Ti-plasmid-encoded genes in the vir regulons of both plasmids. Acetosyringone (AS) induced the expression of all known members of the vir regulons, as well as a small number of additional genes. Unexpectedly, AS also caused a modest induction of virtually every Ti plasmid gene. This suggested that the copy number of the Ti plasmid might increase in response to AS, a hypothesis confirmed by DNA dot blotting. VirA and VirG were the only Vir proteins required for this copy number increase. Promoter resections and primer extension analysis of the repABC promoter region showed that expression of the promoter closest to repA (promoter P4) was induced by AS. We also identified a sequence resembling a consensus VirG-binding motif approximately 70 nucleotides upstream from the P4 transcription start site. Mutating this sequence blocked the AS-induced copy number increase of a RepABC-dependent miniplasmid, indicating that phospho-VirG increases copy number solely by enhancing repABC expression.

Authors+Show Affiliations

Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

16195384

Citation

Cho, Hongbaek, and Stephen C. Winans. "VirA and VirG Activate the Ti Plasmid repABC Operon, Elevating Plasmid Copy Number in Response to Wound-released Chemical Signals." Proceedings of the National Academy of Sciences of the United States of America, vol. 102, no. 41, 2005, pp. 14843-8.
Cho H, Winans SC. VirA and VirG activate the Ti plasmid repABC operon, elevating plasmid copy number in response to wound-released chemical signals. Proc Natl Acad Sci USA. 2005;102(41):14843-8.
Cho, H., & Winans, S. C. (2005). VirA and VirG activate the Ti plasmid repABC operon, elevating plasmid copy number in response to wound-released chemical signals. Proceedings of the National Academy of Sciences of the United States of America, 102(41), 14843-8.
Cho H, Winans SC. VirA and VirG Activate the Ti Plasmid repABC Operon, Elevating Plasmid Copy Number in Response to Wound-released Chemical Signals. Proc Natl Acad Sci USA. 2005 Oct 11;102(41):14843-8. PubMed PMID: 16195384.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - VirA and VirG activate the Ti plasmid repABC operon, elevating plasmid copy number in response to wound-released chemical signals. AU - Cho,Hongbaek, AU - Winans,Stephen C, Y1 - 2005/09/29/ PY - 2005/10/1/pubmed PY - 2006/4/21/medline PY - 2005/10/1/entrez SP - 14843 EP - 8 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc. Natl. Acad. Sci. U.S.A. VL - 102 IS - 41 N2 - The vir genes of Agrobacterium tumefaciens tumor-inducing (Ti) plasmids direct the transfer of oncogenic portion of the Ti (tumor-inducing) plasmid that is transferred to plant cells (T-DNA) into plant cells and are coordinately induced by plant-released phenolic chemical signals. We have used DNA microarrays, representing all genes of the octopine- and nopaline-type Ti plasmids, to identify all Ti-plasmid-encoded genes in the vir regulons of both plasmids. Acetosyringone (AS) induced the expression of all known members of the vir regulons, as well as a small number of additional genes. Unexpectedly, AS also caused a modest induction of virtually every Ti plasmid gene. This suggested that the copy number of the Ti plasmid might increase in response to AS, a hypothesis confirmed by DNA dot blotting. VirA and VirG were the only Vir proteins required for this copy number increase. Promoter resections and primer extension analysis of the repABC promoter region showed that expression of the promoter closest to repA (promoter P4) was induced by AS. We also identified a sequence resembling a consensus VirG-binding motif approximately 70 nucleotides upstream from the P4 transcription start site. Mutating this sequence blocked the AS-induced copy number increase of a RepABC-dependent miniplasmid, indicating that phospho-VirG increases copy number solely by enhancing repABC expression. SN - 0027-8424 UR - https://www.unboundmedicine.com/medline/citation/16195384/VirA_and_VirG_activate_the_Ti_plasmid_repABC_operon_elevating_plasmid_copy_number_in_response_to_wound_released_chemical_signals_ L2 - http://www.pnas.org/cgi/pmidlookup?view=long&pmid=16195384 DB - PRIME DP - Unbound Medicine ER -