Abstract
The moss Physcomitrella patens development starts from a germinating spore that gives rise to a filamentous structure called protonema. Bud that is arisen from protonema develops to give rise to a leafy shoot called gametohpore. After excision of a leaf from a gametophore, leaf cells facing to the dissected cells change to protonemal cells. To explore molecular framework governing the cell cycle reactivation, we investigated temporal and spatial expression patterns of cell cycle regulators in the excised leaves. PpCDKA transcript and protein were constantly detected in P. patens leaf cells and the PpCDKA activity increased in 24 hours after excision. At the same time, PpCYCD gene expression, which is responsible for the PpCDKA activation, was observed. Taken together, our results indicate that the constant expression of PpCDKA is likely related to the immediate reentry of a cell cycle with response to the excision signal, through the PpCYCD expression.
