Specific in vitro interaction between papillomavirus E2 proteins and TBP-associated factors

Area of Science:

• Molecular Biology
• Virology
• Biochemistry

Background:

• Bovine and human papillomavirus (BPV/HPV) E2 proteins regulate viral oncogene transcription by binding to specific DNA sequences.
• E2 proteins function as transcriptional activators, potentially by influencing preinitiation complex assembly.
• Transcription factor IID (TFIID), comprising TATA-binding protein (TBP) and TBP-associated factors (TAFs), is a potential target for viral E2 proteins.

Purpose of the Study:

• To investigate the interaction between BPV/HPV E2 proteins and TAFs.
• To determine which TAFs interact with E2 proteins and identify the binding domains.
• To elucidate how these interactions might explain functional differences between BPV and HPV E2 proteins.

Main Methods:

• In vitro association assays were used to study protein-protein interactions.
• Specific TAFs (TAFII250 and TAFII80) were identified as binding partners for E2 proteins.
• The carboxy-terminal and amino-terminal regions of E2 proteins were analyzed for their roles in TAF binding.

Main Results:

• BPV and HPV E2 proteins associate with TAFII250 and TAFII80.
• TAFII250 shows a stronger association with BPV1 E2 than with HPV18 E2, mediated by the carboxy-terminal domain.
• TAFII80 binds to both BPV and HPV E2 proteins with similar affinity via their amino-terminal regions.

Conclusions:

• The differential binding of E2 proteins to TAFII250 may contribute to the distinct transcriptional activation capabilities of BPV and HPV E2.
• These findings provide insights into the molecular mechanisms underlying papillomavirus transcriptional regulation.
• Understanding E2-TAF interactions is crucial for deciphering viral oncogenesis and developing therapeutic strategies.