Poster abstracts

Poster number 3 submitted by Antje Feller

The many faces of the bHLH transcription factor R

Antje Feller (Plant Cellular and Molecular Biology, OSU), Marcela Hernandez (Dept. of Veterinary Biosciences, OSU), Kengo Morohashi (Plant Celullar and Molecular Biology, OSU), Choon Seok Oh (Plant Celullar and Molecular Biology, OSU), Erich Grotewold (Plant Celullar and Molecular Biology, OSU)

Abstract:
One of the largest transcription factor families in plants is characterized by the presence of a basic-helix-loop-helix (bHLH) domain. The first identified plant bHLH factor corresponded to the product of the maize R gene, which functions as an essential co- activator of C1 (R2R3-MYB) in the activation of maize anthocyanin biosynthetic genes. Besides the highly conserved bHLH domain, R contains three other dimerization interfaces. Here I will introduce three R-interacting factors, Pac1, RIF1 and ZmbHLH5. Pac1 and RIF1 are essential for regulation of anthocyanin biosynthesis by C1 and R and both are part of the transcription factor complex on the A1 promoter. ZmbHLH5 is a novel maize protein which forms heterodimers with the bHLH domain of R. This data presented here shows that R forms a docking site for many proteins and it will be interesting to determine how these proteins cooperate in the combinatorial regulation of gene expression and it may lead to the discovery of novel functions of R.

Keywords: bHLH, protein-protein interaction, combinatorial regulation