细胞松弛素是一类具有异吲哚酮骈合大环骨架的真菌次生代谢产物，其独特的结构和显著的生物功能引起了天然药物研究者的关注。黄柄曲霉素A是从真菌黄柄曲霉中分离得到的自然界首个细胞松弛素二聚体化合物，能显著地诱导癌细胞的细胞周期G1期停滞，却不影响正常细胞的生理功能，具有巨大的药用潜力，但产量相对较低，影响进一步的开发应用。为了突破黄柄曲霉素A化学合成难度大，传统诱变选育高产菌株效率低的限制，进而建立以黄柄曲霉素A生物合成基因簇及其代谢调控机理为前提的定向育种方法，本项目拟在黄柄曲霉基因组、转录组、代谢组的基础上，筛选、克隆黄柄曲霉素A合成基因簇。通过目的基因缺失、过表达及异源表达，结合产生菌的生物学特性及细胞松弛素代谢产物的分析，确定基因簇中与黄柄曲霉素A合成相关的关键合成及调控基因。项目研究成果为利用定向育种和代谢工程技术提高黄柄曲霉素A产量或获得更高活性的细胞松弛素衍生物提供理论与技术支持。

A series of isoindolone paralleled macrocyclic skeletons named cytochalasans from funguses attract much attentions by natural medicine researcher due to their unique structures and significant bioactivites. Asperchalasine A, the first dimer cytochalasan in the nature isolated from the fungus Aspergillus flavipes can induce significant G1-phase cell arrest in cancerous, but not normal, cells. Although medicinal potential asperchalasine A has, the relatively low yield hinders the further development and application. It is the fact that either chemial synthesis of asperchalasine A or traditional mutagenic selection of high yield mutant runs into difficulties. In this project, as an alternative, we study on the biosynthesis and regulation mechanism of asperchalasine A in Aspergillus flavipes, with the purpose to establish a site-derected breeding strategy bsed on the characterization of biosynthesis gene cluster. Firstly, the screening and cloning of the asperchalasine A biosynthetic gene culsters are performed on the basis of genome, transcriptome and metabolome analyses of Aspergillus flavipes. The second, integrate appraches, such as gene deletion, over-expression in producing strain, as well as heterologous expression candidate genges in the yeast were applied to identifiy the functions of the key genes invovled in the asperchalasine A biosythesis and regulation. As is described, this project studys on the biosynthesis and regulation mechanism of asperchalasine A, which provides scientific evidences for Aspergillus flavipes molecular breeding to improve the yield of asperchalasine A. In addition, the characterization of asperchalasine A biosynthetic gene clusters shows clues for discovering and refactoring biosynthtic pathway in other fungi to obstain novel bioactive cytochalasan derivates.