title: Mutations affecting hemolysin production in Listeria monocytogenes located outside the listeriolysin gene.
abstract: We have investigated the molecular basis of spontaneous mutations leading to non-hemolytic and avirulent variants of the Listeria monocytogenes serotype 1/2a strain NCTC 7973 using Southern hybridization to DNA fragments that harbor the listeriolysin gene (hlyA) and adjacent regions cloned from a L. monocytogenes serotype 1/2a strain. The analysis of such non-hemolytic variants revealed the presence of a deletion of 300 base pairs, located 1.6 kb upstream of an otherwise intact listeriolysin gene. The importance of regions upstream of the hlyA gene in controlling the expression of the listeriolysin gene was further emphasized by the detection of a transposon-derived nonhemolytic mutant in which the transposon had inserted approximately 200 bp upstream of the listeriolysin gene. We conclude that at least two elements, contained within a region encompassing 1.6 kb of sequences upstream of the hlyA gene, may be required for expression of the listeriolysin gene.
authors.affiliation: Institut für Genetik und Mikrobiologie, Universität Würzburg, F.R.G.
authors.forename: M
authors.initials: M
authors.lastname: Leimeister-Wächter
authors.forename: W
authors.initials: W
authors.lastname: Goebel
authors.forename: T
authors.initials: T
authors.lastname: Chakraborty
mesh_terms: D001427:Bacterial Toxins; D015139:Blotting, Southern; D004251:DNA Transposable Elements; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D006460:Hemolysin Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D008089:Listeria monocytogenes / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D015183:Restriction Mapping
chemical_list: D001427:Bacterial Toxins; D004251:DNA Transposable Elements; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; C038705:hlyA protein, Listeria monocytogenes