Abstract
Plant cell cycle is tightly controlled by various environmental stresses including elicitors from pathogens. Ubiquitin-mediated proteolysis plays crucial roles in cell cycle regulation, and Anaphase-Promoting Complex/Cyclosome (APC/C) , a multi-subunit E3 ubiquitin ligase, regulates cell cycle in animals and yeasts. Though homologs of all vertebrate APC/C subunits have been computationally identified in Arabidopsis thaliana, functional analyses of APC/C and its subunits are limited in plants. We have been characterizing AtAPC5, APC/C subunit 5 from Arabidopsis. A null atapc5 allele could only be maintained as a heterozygote. Genetic analysis showed that the mutant had female gametophytic defect. Confocal laser scanning microscopic observation of the ovules revealed that the female gametophytes arrested at the one-nucleus stage. We also identified a weak atapc5 allele and characterized its phenotype in planta. We will report phenotypes of loss-of-function mutants as well as overexpressing lines of AtAPC5 and discuss its possible functions.
