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Developmental stage-specific multi-subunit plastid RNA polymerases (PEP) in wheat
1Graduate School of Human and Environmental Studies, Kyoto University, Japan.
The Plant Journal : for Cell and Molecular Biology
|July 16, 1999
Summary
Wheat leaf development alters plastid-encoded RNA polymerase (PEP) activity. PEP transitions from dark- and light-independent in the leaf base to light-dependent in the leaf tip, affecting gene transcription.
Area of Science:
- Plant molecular biology
- Photosynthesis research
- Gene expression regulation
Background:
- Plastid-encoded RNA polymerase (PEP) transcribes most photosystem I and II genes.
- PEP activity and promoter selectivity are crucial for chloroplast development and function.
Purpose of the Study:
- To investigate developmental changes in PEP's promoter selectivity and light-dependency in wheat leaves.
- To understand how these changes impact the transcription of key photosynthetic genes.
Main Methods:
- Analysis of PEP promoter activity at different developmental stages (leaf tip vs. base).
- In vitro transcription assays using purified PEP and sigma 70-type E. coli RNA polymerase.
- Comparison of promoter elements (-35 and extended -10) in different leaf regions.
Main Results:
- PEP activity and light-dependency change significantly during wheat leaf development.
- In the leaf tip, psbA and psbD promoters are light-induced, while others show reduced activity.
- In the leaf base, most PEP promoters function in both light and dark, with distinct promoter element requirements compared to the leaf tip.
Conclusions:
- Wheat leaf development involves a shift in PEP function from constitutive to light-regulated transcription.
- Developmental changes in PEP and its interaction with promoter elements fine-tune gene expression for photosynthesis.