Abstract
In Arabidopsis thaliana, a Histidine-to-Aspartate (His->Asp) phosphorelay is involved in the signal transduction for propagation of certain stimuli, such as plant hormones. Through the phosphorelay, the type-B phospho-accepting response regulator (ARR) family members serve as DNA-binding transcriptional regulators. Based on the fact that this higher plant has 11 type-B ARR family genes, we clarified the expression profiles for all of their transcripts in plants, each carrying a given ARR-promoter::GUS transgene. Comparative studies were also done focusing on ARR20 and ARR21, each of which is a representative member of an uncharacterized minor sub-family. A set of transgenic lines was constructed, in each of which a C-terminal DNA-binding domain was aberrantly overexpressed. These resulting transgenic lines, including ARR14-C-ox, ARR20-C-ox, and ARR21-C-ox, showed characteristic anomalies during development. Together with the results of microarray analyses, these results are discussed with reference to the His ->Asp phosphorelay signal transduction.
