在存在抗坏血酸的情况下，UlaR激活肺炎链球菌中ula操纵子的表达。
UlaR activates expression of the ula operon in Streptococcus pneumoniae in the presence of ascorbic acid.
作者信息
Afzal Muhammad, Shafeeq Sulman, Henriques-Normark Birgitta, Kuipers Oscar P
机构信息
Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, 17177, Stockholm, Sweden.
出版信息
Microbiology (Reading). 2015 Jan;161(Pt 1):41-49. doi: 10.1099/mic.0.083899-0. Epub 2014 Oct 29.
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 strain D39, is studied. β-Galactosidase assay data demonstrate that expression of the ula operon is increased in the presence of ascorbic acid as compared with the effects of other sugar sources including glucose. The ula operon consists of nine genes, including a transcriptional regulator UlaR, and is transcribed as a single transcriptional unit. We demonstrate the role of the 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 PulaA confirmed that the UlaR regulatory site present in PulaA is functional.
在本研究中，我们对肺炎链球菌D39菌株中假定负责抗坏血酸转运和利用的ula（l - 抗坏血酸利用）操纵子的调控机制进行了研究。β - 半乳糖苷酶测定数据表明，与包括葡萄糖在内的其他糖源的作用相比，在抗坏血酸存在的情况下，ula操纵子的表达增加。ula操纵子由九个基因组成，包括一个转录调节因子UlaR，并作为一个单一的转录单元进行转录。我们证明了转录调节因子UlaR在抗坏血酸存在的情况下作为ula操纵子的转录激活因子的作用，并表明UlaR对ula操纵子基因的激活不依赖于CcpA。此外，我们在ulaA的启动子区域预测了一个16 bp的UlaR调控位点（5'-AACAGTCCGCTGTGTA-3'）。ulaA中UlaR调控位点的一半或全部缺失证实了ulaA中存在的UlaR调控位点是有功能的。
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