Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, D.F. 04510, México.
Can J Microbiol. 2012 Oct;58(10):1195-201. doi: 10.1139/w2012-100. Epub 2012 Oct 10.
Streptomyces coelicolor mutants resistant to 2-deoxyglucose are insensitive to carbon catabolite repression (CCR). Total reversion to CCR sensitivity is observed by mutant complementation with a DNA region harboring both glucose kinase glkA gene and the sco2127 gene. The sco2127 is located upstream of glkA and encodes a putative protein of 20.1 kDa. In S. coelicolor, actinorhodin production is subject to glucose repression. To explore the possible involvement of both SCO2127 and glucose kinase (Glk) in the glucose sensitivity of actinorhodin production, this effect was evaluated in a wild-type S. coelicolor A3(2) M145 strain and a sco2127 null mutant (Δsco2127) derived from this wild-type strain. In comparison with strain M145, actinorhodin production by the mutant was insensitive to glucose repression. Under repressive conditions, only minor differences were observed in glucose utilization and Glk production between these strains. SCO2127 was detected mainly during the first 36 h of fermentation, just before the onset of antibiotic production, and its synthesis was not related to a particular carbon source. The glucose sensitivity of antibiotic production was restored to wild-type phenotype by transformation with an integrative plasmid containing sco2127. Our results support the hypothesis that SCO2127 is a negative regulator of actinorhodin production and suggest that the effect is independent of Glk.
变铅青链霉菌 2-脱氧葡萄糖抗性突变体对碳分解代谢物阻遏（CCR）不敏感。通过用含有葡萄糖激酶 glkA 基因和 sco2127 基因的 DNA 区域互补突变体，观察到对 CCR 敏感性的完全回复。sco2127 位于 glkA 上游，编码一个推定的 20.1 kDa 蛋白。在变铅青链霉菌中，放线紫红素的产生受到葡萄糖的抑制。为了探讨 sco2127 和葡萄糖激酶（Glk）在放线紫红素产生的葡萄糖敏感性中的可能作用，在野生型变铅青链霉菌 A3(2) M145 菌株和从该野生型菌株衍生的 sco2127 缺失突变体（Δsco2127）中评估了这种效应。与菌株 M145 相比，突变体的放线紫红素产生对葡萄糖抑制不敏感。在抑制条件下，这两种菌株之间在葡萄糖利用和 Glk 产生方面仅观察到微小差异。SCO2127 主要在发酵的前 36 小时内被检测到，就在抗生素产生开始之前，并且其合成与特定的碳源无关。通过转化含有 sco2127 的整合质粒，将抗生素产生的葡萄糖敏感性恢复到野生型表型。我们的结果支持 SCO2127 是放线紫红素产生的负调控因子的假设，并表明该效应独立于 Glk。
