Abstract：
In this study, an NSDD gene, which encoded a GATA-type transcription factor involved in the regulation and biosynthesis of melanin, pullulan, and polymalate (PMA) in Aureobasidium melanogenum, was characterized. After the NSDD gene was completely removed, melanin production by the Δnsd mutants was enhanced, while pullulan and polymalate production was significantly reduced. Transcription levels of the genes involved in melanin biosynthesis were up-regulated while expression levels of the genes responsible for pullulan and PMA biosynthesis were down-regulated in the Δnsdd mutants. In contrast, the complementation of the NSDD gene in the Δnsdd mutants made the overexpressing mutants restore melanin production and transcription levels of the genes responsible for melanin biosynthesis. Inversely, the complementation strains, compared to the wild type strains, showed enhanced pullulan and PMA yields. These results demonstrated that the NsdD was not only a negative regulator for melanin biosynthesis, but also a key positive regulator for pullulan and PMA biosynthesis in A. melanogenum. It was proposed how the same transcriptional factor could play a negative role in melanin biosynthesis and a positive role in pullulan and PMA biosynthesis. This study provided novel insights into the regulatory mechanisms of multiple A. melanogenum metabolites and the possibility for improving its yields of some industrial products through genetic approaches.
摘要：
在这项研究中,NSDD基因,编码GATA型转录因子，参与黑色素的调节和生物合成，普鲁兰,和多苹果酸盐（PMA）在黑原幼鱼，被表征。在NSDD基因被完全去除后,Δnsd突变体的黑色素产量得到增强，而支链淀粉和多苹果酸的产量显著减少。在Δnsdd突变体中，参与黑色素生物合成的基因的转录水平上调，而负责支链淀粉和PMA生物合成的基因的表达水平下调。相比之下,Δnsdd突变体中NSDD基因的互补使过度表达的突变体恢复了黑色素的产生和负责黑色素生物合成的基因的转录水平。相反，互补菌株，与野生型菌株相比，显示出较高的支链淀粉和PMA产量。这些结果表明，NsdD不仅是黑色素生物合成的负调节剂，也是黑色素A.中普鲁兰和PMA生物合成的关键正调节剂。有人提出了相同的转录因子如何在黑色素生物合成中起负作用，而在支链淀粉和PMA生物合成中起积极作用。这项研究提供了对多种黑色素原A的调节机制的新见解。通过遗传方法提高某些工业产品的产量的可能性。
