Gene Details:

• Gene ID: MELO3C004359P1
• Gene Family: GeBP Family
• Description: GeBP Family protein
• Species: Cucumis melo
• Source: GeBP family gene from PlantTFDB

Protein Features:

• Pfam:  PF04504
• InterPro:  IPR007592

Annotation Proteins:

• Refseq:  XP_011648769.1  — PREDICTED: mediator-associated protein 1
• TrEMBL:  E5GBR9  — E5GBR9_CUCME; Uncharacterized protein
• STRING:  XP_004139376.1  — (Cucumis sativus)
• STRING:  XP_004156488.1  — (Cucumis sativus)

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.

Literature:

• GeBP and GeBP-Like Proteins Are Noncanonical Leucine-Zipper Transcription Factors That Regulate Cytokinin Response in Arabidopsis.   DOI:  10.1104/pp.107.110270 ;  PMID:  18162594

Sequences: