Disease relevance of ros

• Site-directed mutagenesis of Cys-82 and His-92 in this motif showed that these residues are essential for Zn2+ and DNA binding activities of Ros. The existence of such a regulator in Agrobacterium may be due to horizontal interkingdom retrotransfer of the ros gene from plant to bacteria [1].
• The ros gene is highly conserved in members of the Rhizobiaceae [2].

High impact information on ros

• An ipt promoter::cat reporter gene fusion showed a 10-fold increase in ipt promoter activity in A. tumefaciens ros mutant strains when compared with wild type [1].
• Also, increased levels (10- to 20-fold) of isopentenyl adenosine, the product of the reaction catalyzed by isopentenyl transferase, were detected in ros mutant strains [1].
• This mutant affected the expression of exoY but not of ros [3].
• It was shown that the two cysteine residues in the Ros protein were essential for the complementation of the exopolysaccharide synthesis defect of ros mutant strains [3].
• Pleiotropic effects of regulatory ros mutants of Agrobacterium radiobacter and their interaction with Fe and glucose [4].

Chemical compound and disease context of ros

• The ros chromosomal gene is present in octopine and nopaline strains of Agrobacterium tumefaciens as well as in Rhizobium meliloti [5].
• The virulence genes of nopaline (pTiC58) and octopine (pTiA6NC) Ti plasmids are similarly affected by the Agrobacterium tumefaciens ros mutation [6].

Biological context of ros

• The ros mutation is chromosomal in nature and is characterized by a more-than-300-fold increase in the level of expression of bak and a 12-fold increase in the level of expression of an adjacent divergent operon containing the hdv genes, which are involved in some aspect of host specificity [7].
• Genetic and biochemical evidence indicates that the product of the ros locus is a negative regulator of Ti plasmid genes and is related to undefined chromosomally encoded functions that are involved in the mutant phenotype [7].
• Reporter fusion to the ros gene indicates that the level of transcription is controlled in part by autoregulation [5].
• Mapping of the ros virulence regulatory gene of A. tumefaciens [8].
• 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 [9].

Associations of ros with chemical compounds

• The effects of the ros mutation and acetosyringone were cumulative for all vir promoters examined [6].
• The pleiotropic characteristics of the ros mutant include the complete absence of the major acidic capsular polysaccharide [6].

Regulatory relationships of ros

• In both cases, virC was expressed constitutively in the Agrobacterium tumefaciens ros mutant [10].
• Agrobacterium transcriptional regulator Ros is a prokaryotic zinc finger protein that regulates the plant oncogene ipt [1].

Analytical, diagnostic and therapeutic context of ros

• The ros gene was cloned from a genomic bank by electroporation and complementation in Agrobacterium cells [5].

References