A green GEM: intriguing analogies with animal geminin.

The transition of precursor cells from an undifferentiated proliferative state to differentiated cells with specific fates is of primary importance for multicellular organisms. Animals and plants have evolved two unrelated proteins, geminin and GEM, respectively, that play analogous roles in regulating this transition. These proteins are involved, probably in early G1 phase of the cell cycle, in regulating the expression of genes involved in cell fate and initiation of differentiation. They also interact with Cdt1, a component of the pre-replication complexes involved in DNA replication licensing in early G1 phase. The interaction of geminin and GEM with Cdt1 and transcriptional regulators is competitive, suggesting that these interactions can play a pivotal role in coordinating DNA replication, cell division and cell fate decisions.