Disease relevance of vsr

• The vsr gene product of E. coli K-12 is a strand- and sequence-specific DNA mismatch endonuclease [1].
• Identification of the XorII methyltransferase gene and a vsr homolog from Xanthomonas oryzae pv. oryzae [2].

High impact information on vsr

• T:G and U:G mispairs in the methylatable sequence and in related sequences are recognized by the product of vsr, a gene adjacent to dcm [3].
• Mechanism of expression of DNA repair gene vsr, an Escherichia coli gene that overlaps the DNA cytosine methylase gene, dcm [4].
• The Escherichia coli vsr endonuclease recognises T:G base-pair mismatches in double-stranded DNA and initiates a repair pathway by hydrolysing the phosphate group 5' to the incorrectly paired T [5].
• The gene encoding the vsr endonuclease is next to the gene specifying the E. coli dcm DNA-methyltransferase; an enzyme that adds CH3 groups to the first dC within its target sequence CC[A/T]GG, giving C5MeC[A/T]GG [5].
• The addition of vsr on a plasmid to a wild-type lysogen resulted in a 4-fold reduction in mutation at the hotspot [6].

Biological context of vsr

• We find that sufficient Vsr is produced by a single chromosomal copy of vsr to prevent mutagenesis [7].
• This gene, named vsr, is not essential for DNA methylation [8].
• Overexpression of vsr in Escherichia coli stimulates transition and frameshift mutations [9].

Associations of vsr with chemical compounds

• We show that the frequency of occurrence of the mutation is influenced by two genes: dcm, the cytosine methylase gene, and vsr, one of the genes involved in very short patch repair [10].

Other interactions of vsr

• Based on these studies we conclude that there is a six-codon overlap between vsr and dcm [4].

Analytical, diagnostic and therapeutic context of vsr

• This was confirmed using "competitive titrations" (where competitor oligonucleotides are used to displace a (32)P-labelled nucleic acid from the vsr protein) and burst kinetic analysis [11].

References