VirD2 gene product from the nopaline plasmid pTiC58 has at least two activities required for virulence.
AUTOR(ES)
Steck, T R
RESUMO
Virulence genes virD1 and virD2 are required for T-DNA processing in Agrobacterium tumefaciens. The regions within virD2 contributing to T-DNA processing and virulence were investigated. Some insertional mutations in virD2 prevented T-DNA border endonucleolytic cleavage and produced an avirulent phenotype. However, a non-polar insertion immediately after bp 684 of the 1344 bp open reading frame of virD2 did not inhibit endonucleolytic cleavage but still caused a loss of virulence. This suggested that in addition to T-DNA border cleaving activity, the VirD2 protein has another virulence function which resides in the C-terminal half of the protein. Comparative nucleotide sequence analyses of virD2 showed that the first 684 bp were 81% homologous to virD2 of an octopine Ti plasmid whereas the remaining 660 bp were only 44% homologous. A plasmid containing the virD region from octopine Ti plasmid could restore both virulence and processing to a nopaline virD2 mutant. No complementation resulted when a nopaline virD2 clone containing a region similar to eukaryotic nuclear envelope transport sequences was deleted from the 3' end. These results suggest that virD1 and only the first half of virD2 are required to encode for the T-DNA processing endonuclease, and that the 3'-half of virD2 encodes a function separate from endonuclease activity that is required for virulence.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=332755Documentos Relacionados
- Identification of pTiC58 plasmid-encoded proteins for virulence in Agrobacterium tumefaciens.
- TraG from RP4 and TraG and VirD4 from Ti Plasmids Confer Relaxosome Specificity to the Conjugal Transfer System of pTiC58
- Vir box sequences in Agrobacterium tumefaciens pTiC58 and A6.
- Ti plasmid conjugation is independent of vir: reconstitution of the tra functions from pTiC58 as a binary system.
- Opine catabolism and conjugal transfer of the nopaline Ti plasmid pTiC58 are coordinately regulated by a single repressor.