The sae locus of Staphylococcus aureus controls exoprotein synthesis at the transcriptional level (original) (raw)

Abstract

Agr and sar are known regulatory loci of Staphylococcus aureus that control the production of several extracellular and cell-wall-associated proteins. A pleiotropic insertional mutation in S. aureus, designated sae, that leads to the production of drastically diminished levels of α- and β-hemolysins and coagulase and slightly reduced levels of protein A has been described. The study of the expression of the genes coding for these exoproteins in the sae::Tn_551_ mutant (carried out in this work by Northern blot analyses) revealed that the genes for α- and β-hemolysins (hla and hlb) and coagulase (coa) are not transcribed and that the gene for protein A (spa) is transcribed at a somewhat reduced level. These results indicate that the sae locus regulates these exoprotein genes at the transcriptional level. Northern blot analyses also show that the sae mutation does not affect the expression of agr or sar regulatory loci. An sae::Tn_551_ agr::tetM double mutant has been phenotypically characterized as producing reduced or null levels of α-, β-, and δ-hemolysins, coagulase, and high levels of protein A. Northern blot analyses carried out in this work with the double mutant revealed that hla, hlb, hld, and coa genes are not transcribed, while spa is transcribed at high levels. The fact that coa is not expressed in the sae agr mutant, as in the sae parental strain, while spa is expressed at the high levels characteristic of the agr parental strain, suggests that sae and agr interact in a complex way in the control of the expression of the genes of several exoproteins.

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Authors and Affiliations

  1. Departamento de Microbiología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional Río Cuarto, Ruta 36 Km 601, 5800 Río Cuarto, Córdoba, Argentina, , , , , , AR
    A. T. Giraudo & Rosa Nagel
  2. Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA, , , , , , US
    Ambrose L. Cheung

Authors

  1. A. T. Giraudo
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  2. Ambrose L. Cheung
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  3. Rosa Nagel
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Received: 27 August 1996 / Accepted: 7 March 1997

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Giraudo, A., Cheung, A. & Nagel, R. The sae locus of Staphylococcus aureus controls exoprotein synthesis at the transcriptional level.Arch Microbiol 168, 53–58 (1997). https://doi.org/10.1007/s002030050469

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