title: Chromosomal mapping of a gene affecting enterotoxin A production in Staphylococcus aureus.
abstract: In a previous study, transformation demonstrated that a gene governing enterotoxin A production (entA+) in Staphylococcus aureus strain S-6 was located on the chromosome between the purB110 and ilv-129 markers; in contrast, the entA+ gene of strain FRI-196E was shown not to be located in the same position. In the current study, 54 enterotoxin A-producing strains of S. aureus were examined to locate the entA+ gene. Conventional transformation procedures and a series of multiply marked derivatives of NCTC 8325 were used as recipients for chromosomal mapping. Of the 54 strains tested, 23 were found to contain the entA+ gene at the original locus between the purB110 and ilv-129 markers. Twenty-seven strains could not be analyzed either because their DNA was genetically ineffective in transforming strain 8325 (23 strains), or Pur+ Ilv+ transformants could not be recovered (four strains). Four other strains contained an entA+ gene that could not be located in any of the chromosomal linkage groups. A new insertion site for Tn551 was located within the hla+ gene involved in alpha-toxin production. It eliminated alpha-toxin production and was used to separate the entA+ gene from the hla+ marker in the purB110-ilv-129 region. This segment of the chromosome is shown to consist of the purB110, entA+, hla+, and ilv-129 markers in that order.
mesh_terms: D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D004251:DNA Transposable Elements; D004768:Enterotoxins / Q000096:biosynthesis / Q000235:genetics*; D005798:Genes, Bacterial; D008040:Genetic Linkage; D013211:Staphylococcus aureus / Q000235:genetics* / Q000378:metabolism; D014169:Transformation, Bacterial
chemical_list: D004251:DNA Transposable Elements; D004768:Enterotoxins; C026066:enterotoxin A, Staphylococcal