Abstract
Apical meristem is maintained through self-renewal, and gives rise to various tissues and organs. Mosses have two types of merstem cells in gametophytes: protonemal apical cells and gametophore apical cells. To understand molecular mechanism of initiation and maintenance of meristem cells, we have generated gene-trap/enhancer-trap lines to identify genes specifically expressed on the meristem. Here we report a characterization of a et21 gene from an enhancer-trap line ET21 and its Arabidopsis orthologue gene Atet21, which encodes a novel protein. In Physcomitrella, native et21 locus was replaced with et21-GFP translational fusion genes. GFP signal was detected in a nucleus of the apical cells. Atet21 was expressed in the shoot meristem of Arabidopsis. The MSA element responsible for G2/M phase-specific transcription was found in the promoter of both et21 and Ater21. These genes are likely expressed during G2/M phase and function in the apical cells.
