A Novel Interaction Between RAD23A/B and Y-family DNA Polymerases

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Y-family DNA polymerases (Pol ι, Pol η, Pol κ, Rev1) are key players in translesion synthesis (TLS), enabling DNA replication past damage.
• TLS bypasses DNA lesions that stall normal replication forks, maintaining genome integrity.

Purpose of the Study:

• To investigate and characterize novel interactions between Y-family DNA polymerases and nucleotide excision repair (NER) proteins RAD23A and RAD23B.
• To elucidate the binding interfaces and functional significance of these newly identified protein-protein interactions.

Main Methods:

• Biochemical assays to confirm direct interactions.
• Cell-based assays to assess functional consequences.
• Structural analyses to determine binding sites.
• Site-directed mutagenesis to probe the necessity of specific domains.

Main Results:

• Demonstrated a novel interaction between all Y-family polymerases and RAD23A/RAD23B.
• Identified specific binding sites on RAD23A (UBA1 and UBA2 domains) and Pol ι catalytic domain.
• Confirmed that both UBA domains of RAD23A are essential for stable interaction with Pol ι.
• Showed that RAD23 proteins interact similarly with Pol ι and other Y-family polymerases.

Conclusions:

• RAD23A and RAD23B engage in novel interactions with Y-family DNA polymerases.
• These interactions involve distinct binding sites on RAD23A's UBA domains and the Pol ι catalytic domain.
• The findings highlight a potential interplay between TLS and NER pathways through these protein interactions.