PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Raphanus raphanistrum
GeBP Family
Species TF ID Description
RrC10491_p3GeBP family protein
RrC12807_p1GeBP family protein
RrC12807_p2GeBP family protein
RrC1307_p4GeBP family protein
RrC14690_p1GeBP family protein
RrC1484_p2GeBP family protein
RrC15967_p1GeBP family protein
RrC1981_p5GeBP family protein
RrC21904_p1GeBP family protein
RrC22553_p1GeBP family protein
RrC23087_p1GeBP family protein
RrC26004_p1GeBP family protein
RrC2737_p3GeBP family protein
RrC3277_p4GeBP family protein
RrC3287_p4GeBP family protein
RrC3310_p6GeBP family protein
RrC4459_p1GeBP family protein
RrC501_p7GeBP family protein
RrC63_p2GeBP family protein
RrC643_p3GeBP family protein
RrC7614_p1GeBP family protein
RrC7901_p1GeBP family protein
RrC9340_p1GeBP family protein
GeBP Family Introduction

Understanding the role of transcription factors (TFs) is essential in reconstructing developmental regulatory networks. The plant-specific GeBP TF family of Arabidopsis thaliana (Arabidopsis) comprises 21 members, all of unknown function. A subset of four members, the founding member GeBP and GeBP-like proteins (GPL) 1, 2, and 3, shares a conserved C-terminal domain. Here we report that GeBP/GPL genes represent a newly defined class of leucine-zipper (Leu-zipper) TFs and that they play a redundant role in cytokinin hormone pathway regulation. Specifically, we demonstrate using yeast, in vitro, and split-yellow fluorescent protein in planta assays that GeBP/GPL proteins form homo- and heterodimers through a noncanonical Leu-zipper motif located in the C-terminal domain. A triple loss-of-function mutant of the three most closely related genes gebp gpl1 gpl2 shows a reduced sensitivity to exogenous cytokinins in a subset of cytokinin responses such as senescence and growth, whereas root inhibition is not affected. We find that transcript levels of type-A cytokinin response genes, which are involved in the negative feedback regulation of cytokinin signaling, are higher in the triple mutant. Using a GPL version that acts as a constitutive transcriptional activator, we show that the regulation of Arabidopsis response regulators (ARRs) is mediated by at least one additional, as yet unknown, repressor acting genetically downstream in the GeBP/GPL pathway. Our results indicate that GeBP/GPL genes encode a new class of unconventional Leu-zipper TF proteins and suggest that their role in the cytokinin pathway is to antagonize the negative feedback regulation on ARR genes to trigger the cytokinin response.

Chevalier F, Perazza D, Laporte F, Le Henanff G, Hornitschek P, Bonneville JM, Herzog M, Vachon G
GeBP and GeBP-Like Proteins Are Noncanonical Leucine-Zipper Transcription Factors That Regulate Cytokinin Response in Arabidopsis
Plant Physiol. 2008 Mar;146(3):1142-54.
PMID: 18162594