POLARITY IN RELAXED STRAINS OF SALMONELLA TYPHIMURIUM

A relaxed RNA control (rel) mutation of Salmonella typhimurium has been isolated and genetically mapped. As in the Escherichia coli chromosome, the gene order seems to be thy, arg, rel. The effect of polar mutations on the amount of enzyme synthesized by operator-distal genes of the histidine operon has been studied in both stringent and relaxed control strains. No effect of the rel locus on polarity was observed. It is concluded that either the primary function of the rel locus is not to uncouple the processes of translation and transcription, or that such coupling is not the basis of the phenomenon of polarity. © 1968.