biostudies-literatureUnknown102(15)Srikhanta YNSeveral host-adapted bacterial pathogens contain methyltransferases associated with type III restriction-modification (R-M) systems that are subject to reversible, high-frequency on/off switching of expression (phase variation). To investigate the role of phase-variable expression of R-M systems, we made a mutant strain lacking the methyltransferase (mod) associated with a type III R-M system of Haemophilus influenzae and analyzed its phenotype. By microarray analysis, we identified a number of genes that were either up- or down-regulated in the mod mutant strain. This system reports the coordinated random switching of a set of genes in a bacterial pathogen and may represent a widely used mechanism.Proceedings of the National Academy of Sciences of the United States of America5547-51https://www.ebi.ac.uk/biostudies/studies/S-EPMC556257biostudies-literatureThe phasevarion: a genetic system controlling coordinated, random switching of expression of multiple genes.PMC556257Srikhanta YNStacey KJGrimmond SMMaguire TLJennings MPfalseThe phasevarion: a genetic system controlling coordinated, random switching of expression of multiple genes.Several host-adapted bacterial pathogens contain methyltransferases associated with type III restriction-modification (R-M) systems that are subject to reversible, high-frequency on/off switching of expression (phase variation). To investigate the role of phase-variable expression of R-M systems, we made a mutant strain lacking the methyltransferase (mod) associated with a type III R-M system of Haemophilus influenzae and analyzed its phenotype. By microarray analysis, we identified a number of genes that were either up- or down-regulated in the mod mutant strain. This system reports the coordinated random switching of a set of genes in a bacterial pathogen and may represent a widely used mechanism.2005-01-01T00:00:00Z2005 Apr2024-11-13T02:03:28.72Z2019-03-27T01:08:41ZS-EPMC5562571580247110.1073/pnas.0501169102