A Search For Common Regulatory Elements Of DREB2-type Transcription Factors Based On A Molecular Phylogenetic Analysis

Abstract

DREB2A is a transcriptional activator regulating drought- and heat-inducible gene expression. Although many DREB2A homologs have been isolated, low similarity between these genes has made it difficult to deduce which protein has a same function as DREB2A and which residues are functionally important.
We made similarity searches against public databases and identified over 100 proteins similar with DREB2A. Through a molecular phylogenetic analysis of these proteins, we found that DREB2-type proteins could be classified into four subfamilies and that there were several conserved regions shared among subfamilies. Some of these regions were included in previously identified functional domains of DREB2A, suggesting that certain amino acid residues or secondary structures within these regions might be related to common mechanisms for activity regulation. Thus, we introduced mutations into these regions of DREB2A-type proteins from rice and soybean and evaluated the effects of mutations on transcriptional activity.