Microbiology. 2014 Oct 29. pii: mic.0.083899-0. doi: 10.1099/mic.0.083899-0. [Epub ahead of print]
UlaR activates the expression of the ula operon in Streptococcus pneumoniae in the presence of ascorbic acid.
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Abstract
In this study, the regulatory mechanism of the ula (utilization of L-ascorbic acid) operon putatively responsible for transport and utilization of ascorbic acid in Streptococcus pneumoniae D39 strain is studied. β-galactosidase assay data demonstrate that the expression of the ula operon is increased in the presence of ascorbic acid, as compared to the effects of other sugar sources, including glucose. The ula operon consists of nine genes, including a BglG-family transcriptional regulator UlaR, and is transcribed as a single transcriptional unit. We demonstrate the role of the BglG-family transcriptional regulator UlaR as a transcriptional activator of the ula operon in the presence of ascorbic acid and show that activation of the ula operon genes by UlaR is CcpA-independent. Furthermore, we predict a 16-bp regulatory site (5'-AACAGTCCGCTGTGTA-3') for UlaR in the promoter region of ulaA. Deletion of the half- or full UlaR regulatory site in the PulaA confirmed that the UlaR regulatory site present in PulaA is functional.
Copyright © 2014, the Society for General Microbiology.
KEYWORDS:
Ascorbic acid; Pneumococcus; UlaR; carbon source; ula operon
PMID: 25355938 [PubMed - as supplied by publisher]
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