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Two polypeptide chains in yeast transcription factor tau interact with DNA
O S Gabrielsen1, N Marzouki, A Ruet
1Département de Biologie, Centre d'Etudes Nucléaires de Saclay, Gif-sur-Yvette, France.
The Journal of Biological Chemistry
|May 5, 1989
Summary
Yeast transcription factor tau is a multisubunit DNA-binding protein. Two distinct polypeptides, 145-kDa and 100-kDa, are crucial for tau
Area of Science:
- Molecular Biology
- Yeast Genetics
- Transcription Regulation
Background:
- Yeast transcription factor tau binds to intragenic promoters of tRNA genes.
- Understanding the subunit composition of tau is essential for elucidating tRNA gene transcription.
Purpose of the Study:
- To investigate the polypeptide composition of yeast transcription factor tau.
- To identify the specific subunits responsible for DNA binding and transcriptional activity.
Main Methods:
- Improved purification of tau factor.
- Polyacrylamide gel electrophoresis and band shift assays.
- Antibody-based inhibition assays and UV cross-linking experiments.
- Limited proteolysis to generate tau B domain.
Main Results:
- Purified tau contains four major polypeptides (145, 135, 100, and 65 kDa).
- Antibodies against 145-kDa and 100-kDa components inhibit tRNA synthesis.
- UV cross-linking identifies 145-kDa and 100-kDa polypeptides as DNA-binding subunits.
- A tau B domain binds the B block and contains a 120-kDa polypeptide derived from the 145-kDa component.
Conclusions:
- Yeast transcription factor tau is a multisubunit DNA-binding protein.
- The 145-kDa and 100-kDa polypeptides are directly involved in DNA recognition.
- The 145-kDa polypeptide within the tau B domain is responsible for binding to the B block of tRNA gene promoters.