Horinouchi S, Malpartida F, Hopwood D A, Beppu T
Department of Agricultural Chemistry, University of Tokyo, Japan.
Mol Gen Genet. 1989 Jan;215(2):355-7. doi: 10.1007/BF00339742.
The pleiotropic regulatory gene, afsB, from Streptomyces coelicolor A3(2), possibly encoding a DNA-binding protein, is required for actinorhodin production in this organism. Northern blot hybridization using a DNA fragment covering part of the set of cloned actinorhodin biosynthetic gene cluster (act) as the probe showed lack of the act transcripts in an afsB-negative mutant of S. coelicolor A3(2); the transcripts were restored on introduction of a cloned afsB gene. Introduction of the cloned afsB gene into Streptomyces lividans stimulated transcription of the act genes under conditions in which they are normally silent in this strain, leading to production of actinorhodin in large quantity. These data show that afsB exerts its positive regulatory effect by means of transcriptional stimulation of its target genes.
来自天蓝色链霉菌A3(2)的多效调控基因afsB可能编码一种DNA结合蛋白，该基因是这种生物体中放线紫红素产生所必需的。使用覆盖部分克隆的放线紫红素生物合成基因簇（act）的DNA片段作为探针进行Northern印迹杂交，结果显示在天蓝色链霉菌A3(2)的afsB阴性突变体中缺乏act转录本；在导入克隆的afsB基因后，转录本得以恢复。将克隆的afsB基因导入变铅青链霉菌，在该菌株中通常沉默的条件下刺激了act基因的转录，导致大量放线紫红素的产生。这些数据表明，afsB通过对其靶基因的转录刺激发挥其正调控作用。
