PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Sisymbrium irio
GeBP Family
Species TF ID Description
676706490GeBP family protein
676706754GeBP family protein
676707316GeBP family protein
676710418GeBP family protein
676711844GeBP family protein
676716400GeBP family protein
676720428GeBP family protein
676723568GeBP family protein
676724844GeBP family protein
676729786GeBP family protein
676733630GeBP family protein
676745678GeBP family protein
676754294GeBP family protein
676760402GeBP family protein
676760412GeBP family protein
676762152GeBP family protein
676767668GeBP family protein
676768160GeBP family protein
676768814GeBP family protein
676776370GeBP family protein
676776376GeBP family protein
676776378GeBP family protein
676776380GeBP family protein
676776406GeBP family protein
676782494GeBP family protein
676787946GeBP family protein
676788056GeBP family protein
676788502GeBP family protein
676790314GeBP family protein
676792224GeBP 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