Poster abstracts

Poster number 4 submitted by Antje Feller

The Role of the Transcription Factor RED1 in Regulation of Anthocyanin Biosynthesis in maize

Antje Feller (Dept. of Plant Cellular and Molecular Biology and Plant Biotechnology Center, The Ohio State University, Columbus, OH 43210), Que Kong (Dept. Of Plant and Soil Sciences and Kentucky Tobacco Research and Development Center, University of Kentucky), Sitakanta Pattanaik (Dept. Of Plant and Soil Sciences and Kentucky Tobacco Research and Development Center, University of Kentucky), Joshua Werkman (Dept. Of Plant and Soil Sciences and Kentucky Tobacco Research and Development Center, University of Kentucky), Ling Yuan (Dept. Of Plant and Soil Sciences and Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, KY 40546), Erich Grotewold (Dept. of Plant Cellular and Molecular Biology and Plant Biotechnology Center, The Ohio State University, Columbus, OH 43210)

Abstract:
One of the largest transcription factor families in plants is characterized by the presence of a basic-helix-loop-helix (bHLH) domain. This highly conserved domain consists of a stretch of 40-50 amino acid residues which mediate dimerization. Most of these proteins have an adjacent basic region of about 15 amino acids which binds sequence specific to DNA. The first identified plant bHLH factor corresponded to the product of the maize Red1 (R) gene, which functions as an essential co-activator of C1 (R2R3-MYB) in the activation of maize anthocyanin biosynthetic genes. Although the bHLH domain is highly conserved, for maize R no dimerization or DNA binding has been reported. Here we show that the bHLH domain of R is able to homo- and heterodimerize and that it binds to a cis-regulatory element called G-box (CACGTG) independently of C1. In addition, we demonstrate that the previously identified ACT-like domain at the C-terminus of R, which is able to homodimerize and which is necessary for anthocyanin biosynthesis, inhibits DNA binding through the bHLH domain. The results shown here suggest that R can regulate different set of genes depending on the ability to homodimerize through the ACT-like domain or through the bHLH domain.

Keywords: Transcription Factor, Dimerization, DNA binding