XVI International Botanical Congess

We have used a yeast two-hybrid screen to search for proteins that interact with the Arabidopsis homologue of RbAp48, a mammalian protein originally identified by its affinity in vitro for Rb, the retinoblastoma tumor supressor protein. Arabidopsis RbAp48 interacts in yeast with human Rb, as well as with AtTAF1, the product of a member of the Arabidopsis NAC (Nam ATAF Cuc) gene family. Mutations in members of the NAC family result in severe developmental abnormalities. We have have identified two reversed WD-40 repeats in AtTAF1 that are involved in its interaction with RbAp48. A single leucine-for-tryptophan substitution in one of these repeats abolishes the interaction. Current work is focused on further analysis of the RbAp48-AtTAF1 interaction in vitro and cell biological studies of these partners in Arabidopsis tissues.