Regulation of the protein A-encoding gene in Staphylococcus aureus.
The synthesis of several exoproteins, including protein A (SpA) in Staphylococcus aureus is coordinately regulated by the agr locus. Different constructs of the SpA-encoding gene (spa) were introduced into Agr+ and Agr- derivatives of a spa- strain of S. aureus. Plasmid-located spa with deletions at the 3' end expressed a truncated SpA which was almost exclusively extracellular and which confirmed the role of C-terminal region X in cell-wall binding. In the Agr- host, the production of SpA was elevated severalfold. Transcriptional and translational fusions were constructed to study the agr- mediated regulation of spa gene expression. Translational fusions of a beta-lactamase (Bla)-encoding ApR reporter gene with the spa promoter and N-terminal coding sequences expressed elevated levels of Bla activity in the Agr- host. In contrast, a transcriptional fusion of the spa gene with a promoter of the positively regulated staphylococcal epidermolytic toxin A (ETA)-encoding gene synthesized higher levels of SpA in an Agr+ host, as compared to Agr-. Moreover, the synthesis of SpA in the Agr+ strain was switched on during the transition from the exponential to stationary phase in a similar fashion to ETA itself. These data strongly indicate that the regulation of both SpA and ETA occurs at the transcriptional level in S. aureus. The agr-regulated spa promoter was defined by deletion analysis and by transcript mapping.
Patel
A H
AH
Microbiology Department, Trinity College, Dublin, Ireland.
Kornblum
J
J
Kreiswirth
B
B
Novick
R
R
Foster
T J
TJ
D001483:Base Sequence; D015153:Blotting, Western; D004252:DNA Mutational Analysis; D005083:Exfoliatins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013205:Staphylococcal Protein A / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000235:genetics* / Q000254:growth & development; D014158:Transcription, Genetic / Q000235:genetics*
D005083:Exfoliatins; D011993:Recombinant Fusion Proteins; D013205:Staphylococcal Protein A