植物的器官大小是重要的生物学性状，其调控也是一个重要的发育生物学问题。拟南芥DA3编码去泛素化酶UBP14，通过核内复制调控细胞和器官大小，然而DA3调控器官大小的关键蛋白组分及其调节机制还知之甚少。我们曾利用EMS诱变da3突变体，筛选并克隆到两个da3的遗传抑制子MAC3A和MAC3B。在此基础上，拟通过T-DNA插入突变体进一步等位验证这两个抑制子基因突变，利用遗传学方法确定其遗传关系，同时利用生物化学、细胞生物学等方法对DA3与MAC3A/B蛋白功能的互作及调控机制开展系统研究，进一步解析DA3与MAC3A/B调控器官大小的分子机制。因此，本课题的顺利实施将阐明DA3和MAC3A/B协同调控拟南芥器官大小两个分子路径的关系，丰富植物器官大小分子调控网络，具有重要理论意义。

Plant organ size is of great importance in agriculture, thus organ size regulation has attracted significant efforts in developmental biology. DA3, encoding UBIQUITIN-SPECIFIC PROTEASE14 (UBP14), regulates endoreduplication and cell/organ growth. However, the key molecular components of DA3 module and detailed regulating mechanism have not been fully elucidated. We have obtained two DA3 suppressors by screening the EMS mutagenesis populations. Subsequently we have cloned the two suppressor genes (MAC3A and MAC3B). Currently, we are systematically studying the interaction of DA3 and MAC3A/B and the molecular/genetic relationship. By obtaining the T-DNA insertion mutants of MAC3A/B, we will identify the suppressor genes and the genetic relationship of DA3 and MAC3A/B. Meanwhile, with biochemical, cell biology approaches we aim to characterize the roles of DA3- MAC3A/B complex in cell and organ size control. Therefore, this study will illustrate a novel molecular pathway/relationship of coordinated regulations of organ size in Arabidopsis. Our research will have important theoretical significance for agricultural production.