Phase variation controls expression of Salmonella lipopolysaccharide modification genes by a DNA methylation-dependent mechanism
SE Broadbent, MR Davies, MW van der Woude
Molecular Microbiology | WILEY-BLACKWELL | Published : 2010
The O-antigen of Salmonella lipopolysaccharide is a major antigenic determinant and its chemical composition forms the basis for Salmonella serotyping. Modifications of the O-antigen that can affect the serotype include those carried out by the products of glycosyltransferase operons (gtr), which are present on specific Salmonella and phage genomes. Here we show that expression of the gtr genes encoded by phage P22 that confers the O1 serotype is under the control of phase variation. This phase variation occurs by a novel epigenetic mechanism requiring OxyR in conjunction with the DNA methyltransferase Dam. OxyR is an activator or a repressor of the system depending on which of its two bindi..View full abstract
Awarded by Wellcome Trust
We would like to acknowledge the Technology Facility at the Department of Biology, University of York, M. Hodgkinson, E.B. Glennon and T. Taynton for technical support, P. Roberts for photography, M. Susskind for discussions, and S. Casjens and N. Thomson for reagents. This work was supported by the Wellcome Trust (WT080086MA) and S.E.B. was supported by a UK BBSRC graduate studentship.