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Proteins that bind to the yeast rDNA enhancer.
B E Morrow1, S P Johnson, J R Warner
1Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461.
The Journal of Biological Chemistry
|May 25, 1989
Summary
Researchers discovered two proteins, REB1 and REB2, that bind to a ribosomal RNA gene enhancer in yeast. These proteins are crucial for regulating rRNA gene transcription and DNA conformation.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Ribosomal RNA (rRNA) gene transcription in yeast (Saccharomyces cerevisiae) is unique, involving specialized polymerases, high transcription levels, and tandem gene arrangements.
- A regulatory sequence within the non-transcribed spacer region of rRNA genes exhibits enhancer-like properties and is involved in transcription and termination.
Purpose of the Study:
- To identify protein factors that bind to the rRNA gene enhancer.
- To investigate the role of these proteins in the activation and termination of rRNA gene transcription.
Main Methods:
- Electrophoretic mobility shift assays (EMSA) to detect protein-DNA interactions.
- DNase footprinting assays to map protein binding sites on the DNA.
- Analysis of DNA conformation changes upon protein binding.
Main Results:
- Identification of two proteins, REB1 and REB2, that specifically bind to the rRNA gene enhancer sequence.
- REB1 and REB2 binding protects distinct DNA regions within the enhancer.
- A second REB1 binding site was found upstream of the rRNA transcription origin, influencing DNA conformation near the initiation site.
Conclusions:
- REB1 and REB2 are key regulatory proteins involved in controlling yeast rRNA gene transcription.
- These proteins likely play a role in the coordinated regulation of adjacent rRNA genes.
- REB1 binding can modulate DNA structure, potentially impacting transcription initiation.