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Maize ABI4 binds coupling element1 in abscisic acid and sugar response genes
Xiping Niu1, Tim Helentjaris, Nicholas J Bate
1Agronomic Traits, Trait and Technology Development, Pioneer Hi-Bred International, Johnston, IA 50131-0552, USA.
The Plant Cell
|October 9, 2002
Summary
Researchers identified a maize protein, ZmABI4, that binds to a key element (CE1) involved in abscisic acid (ABA) signaling. This discovery links ABA-regulated gene expression to kernel development and sugar responses.
Area of Science:
- Plant Molecular Biology
- Plant Physiology
- Gene Regulation
Background:
- Abscisic acid (ABA) regulates gene expression through elements like ABRE and CE1.
- Transcription factors binding to ABRE are known, but the factor for CE1 remained uncharacterized.
Purpose of the Study:
- To identify and characterize the trans-acting factor that interacts with the CE1 element in ABA-regulated gene expression.
- To investigate the role of this factor in both ABA and sugar signaling pathways.
Main Methods:
- Isolation of a seed-specific maize ABI4 homolog (ZmABI4).
- PCR-based in vitro selection to determine ZmABI4 binding to CE1-like sequences.
- Electrophoretic mobility shift assays (EMSA) to confirm ZmABI4 binding to CE1 in ABA-related genes.
- Complementation studies in Arabidopsis abi4 mutant plants.
Main Results:
- Maize ABI4 (ZmABI4) protein was isolated and shown to bind to the CE1-like sequence CACCG.
- Recombinant ZmABI4 protein binds to the CE1 element in ABA-responsive genes.
- ZmABI4 also binds to the promoter of the sugar-responsive ADH1 gene.
- ZmABI4 complements the ABA- and sugar-sensitive phenotype of Arabidopsis abi4 mutant plants.
Conclusions:
- ZmABI4 is a trans-acting factor that binds to the CE1 element, linking ABA-mediated kernel development to ABA response gene regulation.
- ZmABI4 plays a role in both ABA and sugar signaling pathways.
- This identification provides a crucial link in understanding complex plant regulatory networks.