Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
PLoS Genet. 2013;9(1):e1003193. doi: 10.1371/journal.pgen.1003193. Epub 2013 Jan 17.
Secondary metabolism and development are linked in Aspergillus through the conserved regulatory velvet complex composed of VeA, VelB, and LaeA. The founding member of the velvet complex, VeA, shuttles between the cytoplasm and nucleus in response to alterations in light. Here we describe a new interaction partner of VeA identified through a reverse genetics screen looking for LaeA-like methyltransferases in Aspergillus nidulans. One of the putative LaeA-like methyltransferases identified, LlmF, is a negative regulator of sterigmatocystin production and sexual development. LlmF interacts directly with VeA and the repressive function of LlmF is mediated by influencing the localization of VeA, as over-expression of llmF decreases the nuclear to cytoplasmic ratio of VeA while deletion of llmF results in an increased nuclear accumulation of VeA. We show that the methyltransferase domain of LlmF is required for function; however, LlmF does not directly methylate VeA in vitro. This study identifies a new interaction partner for VeA and highlights the importance of cellular compartmentalization of VeA for regulation of development and secondary metabolism.
次级代谢和发育在曲霉中通过保守的调节 velvet 复合物联系在一起,该复合物由 VeA、VelB 和 LaeA 组成。velvet 复合物的创始成员 VeA 响应光的变化在细胞质和核之间穿梭。在这里,我们通过反向遗传学筛选描述了一个通过反向遗传学筛选鉴定的 VeA 的新相互作用伙伴,该筛选旨在寻找 Aspergillus nidulans 中的 LaeA 样甲基转移酶。鉴定出的一个假定的 LaeA 样甲基转移酶,LlmF,是麦角甾酮产生和有性发育的负调节剂。LlmF 与 VeA 直接相互作用,LlmF 的抑制功能是通过影响 VeA 的定位来介导的,因为过量表达 llmF 会降低 VeA 的核质比,而删除 llmF 会导致 VeA 在核内积累增加。我们表明,LlmF 的甲基转移酶结构域是其功能所必需的;然而,LlmF 不能在体外直接甲基化 VeA。这项研究鉴定了 VeA 的一个新的相互作用伙伴,并强调了 VeA 的细胞区室化对于发育和次生代谢调节的重要性。