Multiple Mechanisms of Transcriptional Repression by YY1
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Discussion
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Implication
Mechanistic analysis reveals distinct activator-specific repression modes by YY1 zinc fingers, indicating context-dependent inhibition of transcription machinery.
Key Points
- Investigate the molecular mechanisms by which the zinc finger domains of YY1 mediate transcriptional repression and evaluate proposed DNA-bending and coactivator-quenching models.
- Evaluated the functional roles of the four C-terminal GLI-Krüppel type zinc fingers of YY1 using a structure-and-function mutational panel.
- Assessed DNA binding and repression activities against transcription factors CTF-1, Sp1, and CREB, as well as the coactivator p300.
- Identified zinc finger 2 as essential for both DNA binding and transcriptional repression, though mutational separation of these functions refutes the DNA-bending repression model.
- Showed that physical interaction between YY1 and p300 is insufficient to repress CREB-mediated transcription.
- Demonstrated activator-specific repression where YY1 directly binds CTF-1 to inhibit transcription, but represses Sp1 and CREB without requiring direct physical interactions.
Cite This Study
Galvin et al. (1997) studied this question.