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Ethylene control of E4 transcription during tomato fruit ripening involves two cooperative cis elements
1Department of Biology, 208 Mueller Laboratory, Pennsylvania State University Park 16802, USA.
Plant Molecular Biology
|September 1, 1996
Summary
Ethylene controls tomato fruit ripening by regulating E4 gene transcription. Researchers identified two key DNA regions essential for this ethylene response, crucial for understanding fruit development.
Area of Science:
- Plant Molecular Biology
- Gene Regulation
- Fruit Ripening
Background:
- Ethylene is a key hormone regulating tomato fruit ripening.
- The E4 gene's transcription is known to be controlled by ethylene.
- Understanding the specific promoter elements involved is crucial for deciphering this regulation.
Purpose of the Study:
- To define the specific ethylene-responsive promoter elements of the tomato E4 gene.
- To investigate the role of the E4/E8 binding protein in E4 gene transcription.
Main Methods:
- Utilized linker scan mutations within the E4 promoter region (-160 to -91 bp).
- Constructed chimeric genes by fusing E4 promoter fragments to a minimal 35S promoter.
- Performed transient assays to measure gene transcription levels and ethylene responsiveness.
Main Results:
- Identified a critical region between -150 and -121 bp required for normal ethylene-regulated transcription.
- Demonstrated that E4 sequences from -193 to -40 bp did not confer ethylene responsiveness alone.
- Found that mutations affecting E4/E8 binding protein affinity reduced E4 gene activity, suggesting its regulatory role.
Conclusions:
- At least two distinct cis-acting elements are necessary for ethylene-responsive E4 gene transcription during tomato fruit ripening.
- One element is located between -150 and -121 bp, and another is between -40 and +65 bp.
- The E4/E8 binding site, while important, is not sufficient on its own for ethylene response.