Open AccessA single amino acid substitution beyond the C2H2‐zinc finger in Ros derepresses virulence and T‐DNA genes in Agrobacterium tumefaciens
Author(s) -
Archdeacon John,
Bouhouche Naima,
O'Connell Fergus,
Kado Clarence I
Publication year - 2000
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2000.tb09156.x
Subject(s) - agrobacterium tumefaciens , zinc finger , mutant , biology , gene , ti plasmid , octopine , repressor , plasmid , virulence , microbiology and biotechnology , genetics , gene expression , transcription factor , transformation (genetics)
Ros is a chromosomally‐encoded repressor containing a novel C2H2 zinc finger in Agrobacterium tumefaciens . Ros regulates the expression of six virulence genes and an oncogene on the Ti plasmid. Constitutive expression of these genes occurs in the spontaneous mutant 4011R derived from the octopine strain Ach‐5, resulting in T‐DNA processing in the absence of induction, and in the biosynthesis of cytokinin. Interestingly, the mutation in 4011R is an Arg to Cys conversion at amino acid residue 125 near the C‐terminus well outside the zinc finger of Ros. Yet, Ros bearing this mutation is unable to bind to the Ros‐box and is unable to complement other ros mutants.