Transcriptional regulation of the Streptococcus mutans gal operon by the GalR repressor

Dragana Ajdic, Joseph J. Ferretti

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The galactose operon of Streptococcus mutans is transcriptionally regulated by a repressor protein (GalR) encoded by the galR gene, which is divergently oriented from the structural genes of the gal operon. To study the regulatory function of GalR, we partially purified the protein and examined its DNA binding activity by gel mobility shift and DNase I footprinting experiments. The protein specifically bound to the galR-galK intergenic region at an operator sequence, the position of which would suggest that GalR plays a role in the regulation of the gal operon as well as autoregulation. To further examine this hypothesis, transcriptional start sites of the gal operon and the galR gene were determined. Primer extension analysis showed that both promoters overlap the operator, indicating that GalR most likely represses transcription initiation of both promoters. Finally, the results from in vitro binding experiments with potential effector molecules suggest that galactose is a true intracellular inducer of the galactose operon.

Original languageEnglish
Pages (from-to)5727-5732
Number of pages6
JournalJournal of Bacteriology
Volume180
Issue number21
StatePublished - Nov 1 1998
Externally publishedYes

Fingerprint

Streptococcus mutans
Operon
Galactose
Genes
Repressor Proteins
Intergenic DNA
Deoxyribonuclease I
Proteins
Homeostasis
Gels
DNA

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology

Cite this

Transcriptional regulation of the Streptococcus mutans gal operon by the GalR repressor. / Ajdic, Dragana; Ferretti, Joseph J.

In: Journal of Bacteriology, Vol. 180, No. 21, 01.11.1998, p. 5727-5732.

Research output: Contribution to journalArticle

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