GEM, a Novel Factor in the Coordination of Cell Division to Cell Fate Decisions in the Arabidopsis Epidermis.

Cell division and cell fate decisions are highly regulated processes that need to be coordinated both spatially and temporally for correct plant growth and development. Gaining a deeper molecular and cellular understanding of these links is especially relevant for plant biology since, unlike in animals, formation of new organs is a process that takes place after embryogenesis and continues throughout the entire plant lifespan. The recent identification of a novel factor, GEM, has provided a molecular framework that coordinates cell division to cell fate in the Arabidopsis epidermis. GEM is an inhibitor of cell division through interacting with CDT1, a DNA replication protein. It also inhibits the expression of the homeobox GLABRA2 (GL2) gene that determines the hair/non-hair fate and the pavement/trichome fate in the root and leaf epidermis, respectively. GEM seems to be crucial in controlling the balance of activating/repressing histone modifications at its target promoters.