CIF150, a human cofactor for transcription factor IID-dependent initiator function

Area of Science:

• Molecular Biology
• Gene Regulation
• Biochemistry

Background:

• Transcription factor IID (TFIID) is vital for gene transcription and is conserved across species.
• Most Drosophila TAFs have mammalian homologs, except dTAF(II)150.
• CIF is a known cofactor for TFIID-dependent transcription at initiator (Inr) elements.

Purpose of the Study:

• To clone and characterize the human homolog of dTAF(II)150.
• To investigate the role of this human homolog in initiator (Inr) element activity.
• To elucidate the interaction of this factor with the human TFIID complex.

Main Methods:

• Molecular cloning of the human homolog of dTAF(II)150 (CIF150).
• Biochemical assays to assess Inr activity mediation.
• Complementation assays to evaluate CIF150's functional role.
• In vitro binding assays to determine protein interactions.

Main Results:

• CIF150, the human homolog of dTAF(II)150, was cloned.
• CIF150 mediates TFIID-dependent Inr activity.
• CIF150 interacts directly with hTAF(II)135.
• CIF150 stabilizes TFIID binding to core promoters, despite not being part of the canonical human TFIID complex.

Conclusions:

• CIF150 plays a significant role in initiator element-driven transcription in humans.
• CIF150's interaction with hTAF(II)135 is important for its function.
• CIF150 enhances TFIID function by stabilizing its core promoter binding.