生长素在植物生长发育中起重要作用，但是它控制器官发生的机制还不清楚。为了探寻参与生长素控制器官发生的新基因，我们通过遗传筛选获得了一个拟南芥幼苗和胚胎子叶缺失的突变体ncp104 pid，发现NCP104编码VPS28A。VPS28A和PID的突变导致ncp104 pid子叶缺失。VPS28A是内体蛋白分选转运复合体(ESCRT)的成员。该复合体由多个成员组成，参与多泡体的生物发生，将泛素化修饰的膜蛋白分选进入腔内小泡，并最终进入液泡降解的过程。拟南芥ESCRT-I复合体由VPS23、VPS28、VPS37三种蛋白组成，都有A、B两种同工型，它们在生长发育中的作用还不清楚。ncp104是VPS28A的一个特殊的等位突变体。本项目将鉴定vps28及相关突变体的发育表型，解析VPS28的表达模式和蛋白定位、互作蛋白及其在膜蛋白转运和降解中的作用，揭示其在调控生长素作用和器官发生中的作用机制。

Auxin plays important roles in plant growth and development. However, the mechanisms by which auxin controls organogenesis have not been well understood. To discover new genes involved in auxin regulated organogenesis, we carried out a genetic screen and isolated a no-cotyledon mutant ncp104 pid. Our molecular cloning and complementation experiments demonstrated that NCP104 encodes VPS28A, which is a component of endosomal sorting complex required for transport (ESCRT). The ESCRT machinery is composed of 5 multi-component complexes. It plays essential roles in the biogenesis of the multi-vesicular body and the sorting of ubiquitinated membrane proteins into their intraluminal vesicles and finally into vacuole for degradation. The Arabidopsis ESCRT-I complex consists of VPS23, VPS28 and VPS37, each has A and B isoforms but their roles in growth and development have not been well understood. We found that ncp104 was a special allele of VPS28A. In this project, we will characterize the phenotypes of vps28 and related mutants. We will dissect the gene expression patterns, protein subcellular localizations, interacting proteins of VPS28A/B, and their roles in trafficking and degradation of membrane proteins, to reveal the mechanisms VPS28A/B regulate auxin action and organogenesis.