ISOLATION OF PUTATIVE PLANT TRANSCRIPTIONAL COACTIVATORS USING A MODIFIED 2-HYBRID SYSTEM INCORPORATING A GFP REPORTER GENE

Dual hybrid interacting screening in yeast led to the identification o f two proteins from Arabidopsis both exhibiting sequence similarity to a family of transcriptional coactivators from a diverse range of orga nisms. Their discovery constitutes the first description of such plant proteins. A modified yeast two-hybrid approach utilising the green fl uorescent protein (GFP) of Aequora victoria was developed and used to clone one of the putative plant transcriptional coactivators from an A rabidopsis cDNA library. The two proteins, designated KIWI and KELP, c an associate both hetero- and homomerically and their genes were clone d and mapped on the Arabidopsis genome. Both proteins are believed to play a role in gene activation during pathogen defence and plant devel opment. The involvement of these proteins in general plant transcripti on as well as the advantages of using GFP as a reporter gene for detec ting protein-protein interactions are discussed.