Abstract
Asymmetric cell division in a stem cell generates two different daughter cells; one is a self-renewed stem cell daughter and the other is a differentiated, non-stem cell daughter. Although unequal distribution of mRNA or proteins has been known to play a pivotal role to specialize each daughter cell, such molecules in plants remain largely unknown. The isolated protoplasts of P. patens divide asymmetrically to generate stem cells and differentiated non-stem cells, assuring a good system for the study of molecular mechanisms for asymmetric cell division. We transiently overexpressed P. patens cDNAs in the protoplasts and identified 58 genes as candidates involved in asymmetric cell division. For those candidates, we made cDNA-YFP knock-in transgenic plants by using gene targeting technique to investigate protein localization under a control of their native promoters. We found nine proteins accumulated preferentially in the stem cells but not in differentiated protonemal cells.
