We have isolated an Arabidopsis protein designated 1-2 Ara, which activates transcription from a LexA-specific promoter in yeast. The 1-2 Ara protein specifically binds to the LexA operator sites and activates expression of the lacZ and HIS3+ reporter genes. 1-2 Ara binding to the LexA operators was specific because 1-2 Ara did not recognize the Gal4-inducible promoter. To understand whether 1-2 Ara has functions similiar to the bacterial LexA protein, we use an indicator E. coli strain which allows to specifically assay the LexA-mediated repression activity. Studies on molecular cloning and expression of 1-2 Ara for further analyses are in progress.