Identification of Genes Involved in Cell Polarity, Asymmetric Cell Division or Cell Differentiation by Overexpression of Full-length cDNAs in the Moss Physcomitrella Patens

Abstract

Asymmetric cell division is of fundamental importance in the generation of the overall cellular pattern. Its molecular mechanism, however, remains unknown in plants. Regeneration of protoplasts in the moss, Physcomitrella patens assures a good system for the study of molecular mechanisms such as cell polarity, asymmetric cell division, and cell differentiation. We have devised a comprehensive system to screen genes affecting the regeneration step of protoplasts in P. patens.
We used full-length cDNA clones, whose sequences were determined from both ends, and >2,000 cDNAs were selected based on their sequence, subcloned under a constitutive promoter, then introduced into moss protoplasts for overexpression. We scored the phenotypes of regeneration of the protoplasts. About 5% of cDNAs caused abnormal regeneration at various degrees, some of which encode cytoskeletal proteins, signal transduction, unknown proteins and novel proteins. We will present the current status of this project.