Staphylococcal enterotoxin A gene is associated with a variable genetic element

Proc Natl Acad Sci U S A. 1984 Aug;81(16):5179-83. doi: 10.1073/pnas.81.16.5179.

Abstract

The genetic determinant of Staphylococcus aureus enterotoxin A (SEA) has been cloned in pBR322 in Escherichia coli and found to be expressed and secreted into the periplasmic space in that organism. The SEA gene (entA) is within a 2.5-kilobase-pair HindIII fragment that is part of a discrete genetic element 8-12 kilobase pairs in length. This entA element has a standard chromosomal location [between the purine (pur) and isoleucine-valine (ilv) markers] in most S. aureus strains. In some strains it is unlinked to pur-ilv. However, its internal structure is conserved at different locations. Some naturally occurring SEA-nonproducer (EntA-) strains lack the entire entA element, and one instance of its spontaneous loss is reported. Other naturally occurring strains have EntA- structural variants of the element at the same pur-ilv location at which the intact element is most commonly found. Some of these strains are EntA-, others are EntA+; the latter have a second, unlinked copy of the element containing their functional entA gene. These results suggest that entA is associated with a structurally unstable, possibly mobile, discrete genetic element.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • DNA Restriction Enzymes
  • Enterotoxins / genetics*
  • Escherichia coli / genetics
  • Genes*
  • Genes, Bacterial*
  • Genotype
  • Nucleic Acid Hybridization
  • Plasmids
  • Species Specificity
  • Staphylococcus aureus / genetics*

Substances

  • Enterotoxins
  • enterotoxin A, Staphylococcal
  • DNA Restriction Enzymes