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The PER2:BRCA1:POU2F1(OCT-1) ternary complex represents a multi-component scaffold model for circadian gene
Elizaveta Kadukhina1,2, Siqi Jia1,2, Linda M Villa2
1Fralin Biomedical Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA, 24016, USA.
Neurobiology of Sleep and Circadian Rhythms
|June 22, 2026
Summary
The circadian clock protein PER2 forms a complex with BRCA1 and POU2F1(OCT-1) to control gene expression. This discovery reveals how PER2 acts as a scaffold, influencing transcription and circadian rhythms.
Area of Science:
- Molecular Biology
- Chronobiology
- Genetics
Background:
- The circadian clock component Period 2 (PER2) regulates daily gene expression, but its role in protein complex assembly is unclear.
- Understanding how PER2 interacts with other proteins is crucial for deciphering circadian regulatory mechanisms.
Purpose of the Study:
- To investigate the role of PER2 in assembling multi-protein regulatory complexes.
- To identify novel PER2-interacting proteins and elucidate their function in circadian transcription.
Main Methods:
- Bacterial two-hybrid screening to identify PER2-interacting proteins.
- Biochemical mapping and structural modeling to analyze protein-protein interactions.
- In vitro pull-down and electrophoretic mobility shift assays to study complex formation and DNA binding.
- Circadian transcriptome analysis in mouse models.
Main Results:
- BRCA1 was identified as a novel PER2-interacting protein, forming a ternary complex with PER2 and POU2F1(OCT-1).
- PER2 interacts with BRCA1 via multiple interfaces, suggesting differential affinities for ordered complex assembly.
- BRCA1 is essential for stabilizing PER2 recruitment to DNA-bound POU2F1(OCT-1), regulating target gene promoters like ESR1.
- PER2 acts as a circadian scaffold, temporally gating transcription.
Conclusions:
- PER2, BRCA1, and POU2F1(OCT-1) form a ternary complex that imposes circadian control on target gene promoters.
- This mechanism provides insight into how circadian disruption affects gene expression.
- PER2 functions as a crucial scaffold protein in circadian transcriptional regulation.
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