PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Nicotiana tabacum
GeBP Family
Species TF ID Description
XP_016437432.1GeBP family protein
XP_016452114.1GeBP family protein
XP_016459167.1GeBP family protein
XP_016461631.1GeBP family protein
XP_016470442.1GeBP family protein
XP_016473271.1GeBP family protein
XP_016475702.1GeBP family protein
XP_016476085.1GeBP family protein
XP_016480385.1GeBP family protein
XP_016481909.1GeBP family protein
XP_016488993.1GeBP family protein
XP_016489373.1GeBP family protein
XP_016493197.1GeBP family protein
XP_016496498.1GeBP family protein
XP_016507116.1GeBP family protein
XP_016508976.1GeBP 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