Identification Of Genes Involved In Cell Polarity Or Asymmetric Cell Division By Overexpression Of Full-length cDNAs During Protoplast Regeneration Of 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 for cell polarity or asymmetric cell division. We have devised a systematic overexpression screening for genes affecting the regeneration step of protoplasts in P. patens.
We transiently overexpressed >3,000 of full-length cDNAs, which were selected based on their sequence and subcloned under a constitutive promoter. We observed and categorized phenotypes of regeneration of the protoplasts. We identified cDNAs, whose overexpression resulted in symmetric cell division rather than asymmetric cell division, isotropic outgrowth with no polarity or curved cells showing incorrect direction of growth, indicating that some of genes identified may have roles for polarity formation or asymmetric cell division of the protoplasts.