Plant Transcription Factor Database
Previous version: v3.0
Thellungiella parvula
GeBP Family
Species TF ID Description
Tp1g10140GeBP family protein
Tp2g02820GeBP family protein
Tp2g20280GeBP family protein
Tp3g03750GeBP family protein
Tp3g27600GeBP family protein
Tp3g27630GeBP family protein
Tp4g18590GeBP family protein
Tp4g18600GeBP family protein
Tp7g04640GeBP family protein
Tp7g04750GeBP family protein
Tp7g05050GeBP family protein
Tp7g05370GeBP family protein
Tp7g05390GeBP family protein
Tp7g05550GeBP family protein
Tp7g05700GeBP family protein
Tp7g05720GeBP family protein
Tp7g05730GeBP family protein
Tp7g11180GeBP family protein
Tp7g11190GeBP family protein
Tp7g23230GeBP family protein
Tp_un0005_003GeBP family protein
Tp_un0005_014GeBP family protein
Tp_un0006_003GeBP family protein
Tp_un0006_014GeBP family protein
Tp_un0032_002GeBP family protein
Tp_un0053_001GeBP family protein
Tp_un0053_003GeBP 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