Disease relevance of hsdR

• The Sau1 type I restriction-modification system is found on the chromosome of all nine sequenced strains of Staphylococcus aureus and includes a single hsdR (restriction) gene and two copies of hsdM (modification) and hsdS (sequence specificity) genes [1].
• We show that Ral enhances modification in a host strain lacking the entire hsdR gene, and lambda phages carrying the hsdM and S genes modify their own DNA inefficiently in the absence of Ral, despite the fact that derivatives of these phages provide efficient amplification of the K-specific methylase [2].
• A probe comprising most of the hsdR gene and all of the hsdM and S genes of E. coli K 12 shares extensive homology with the DNA of E. coli B but none with that of E. coli C [3].
• Joining of simian virus 40 DNA molecules at endonuclease R Eco Ri sites by polynucleotide ligase and analysis of the products by agarose gel electrophoresis [4].

High impact information on hsdR

• This enzyme, designated endonuclease R Dpn II, produces a similar pattern of fragments from the DNA of T7 without prior methylation of the DNA [5].
• Transposon mutagenesis was used to locate the positions of the hsdR, hsdM, and hsdS genes on the cloned fragments in conjunction with complementation tests for gene function [6].

Analytical, diagnostic and therapeutic context of hsdR

• Three genes, whose products are required for K-specific restriction and modification, have been identified by complementation tests as hsdR, M and S [3].

References