Lubelska Joanna M, Jonuscheit Melanie, Schleper Christa, Albers Sonja-Verena, Driessen Arnold J M
Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9751 NN Haren, The Netherlands.
Extremophiles. 2006 Oct;10(5):383-91. doi: 10.1007/s00792-006-0510-7. Epub 2006 Apr 8.
Sugar uptake in Sulfolobus solfataricus, a thermoacidophilic archaeon, occurs through high-affinity binding of protein-dependent ABC transporters. We have investigated the expression patterns of two sugar transport operons, that is, the glucose and arabinose transporters. Analysis of the araS promoter activity, and the mRNA and protein levels in S. solfataricus cells grown on different carbon sources showed that expression of the arabinose transporter gene cluster is highly regulated and dependent on the presence of arabinose in the medium. Glucose in the growth medium repressed the expression of the arabinose transport genes. By means of primer extension, the transcriptional start site for the arabinose operon was mapped. Interestingly, expression of the arabinose transporter is down-regulated by addition of a selective set of amino acids to the medium. Expression of the glucose transporter genes appeared constitutive. These data confirm the earlier observation of a catabolite repression-like system in S. solfataricus.
嗜热嗜酸古菌嗜热栖热菌中的糖摄取是通过蛋白质依赖性ABC转运蛋白的高亲和力结合来实现的。我们研究了两个糖转运操纵子的表达模式，即葡萄糖和阿拉伯糖转运体。对araS启动子活性以及在不同碳源上生长的嗜热栖热菌细胞中的mRNA和蛋白质水平进行分析，结果表明阿拉伯糖转运体基因簇的表达受到高度调控，并且依赖于培养基中阿拉伯糖的存在。生长培养基中的葡萄糖会抑制阿拉伯糖转运基因的表达。通过引物延伸法，确定了阿拉伯糖操纵子的转录起始位点。有趣的是，向培养基中添加一组特定的氨基酸会下调阿拉伯糖转运体的表达。葡萄糖转运体基因的表达似乎是组成型的。这些数据证实了之前在嗜热栖热菌中观察到的类似分解代谢物阻遏的系统。
