Abstract
ARR1 (Arabidopsis response regulator 1) is a transcription factor that responds a cytokinin signal mediated by His-Asp phosphorelay and directly activates immediately responsive genes. It binds DNA sequences, 5'-(G/A)GAT(T/C)-3', specifically.
We analyzed involvement of sequence structures of cytokinin-responsive promoters in their cytokinin responsivity. To reveal genes which ARR1 directly activates, we examined mRNA levels of 11 A-type ARRs and other immediately responsive genes to cytokinin, using transgenic plants in which transactivating function of ARR1 can be controlled artificially. Then we analyzed upstream sequences of the identified direct target genes. From these results we will discuss the essential structure of promoter sequences that recognized by ARR1 on the cytokinin response.
