Abstract
Asymmetric cell division, generating two cell types from one, is important to understand mechanisms of ontogenesis in animals and in plants. The various events of asymmetric cell division should be tightly coupled to a cell-cycle regulation. One of the important links between cell-cycle regulation and asymmetric cell division has been reported in cyclin-dependent kinase Cdc2 of Drosophila melanogaster. Attenuation of its Cdc2 function resulted in a symmetric cell division in the neural precursor cell, which normally divides asymmetrically. While homozygous mutant of Arabidopsis thaliana CDKA;1, a homologue of Cdc2, is lethal, little is known about how CDKA functions in a process of asymmetric cell division in plants.
A protonemal apical cell of the moss, Physcomitrella patens provides a good system for the study of asymmetric cell division at a single cell level. P. patens has two copies of CDKA in the genome, and to investigate the function of CDKA in the process of asymmetric cell division, we made double knock-out lines of CDKA by homologous recombination. Thus we will report their phenotypes and discuss the function.
