The human HELQ helicase and XRN2 exoribonuclease cooperate in R-loop resolution

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Human HELQ helicase (Helicase with RNAse H-like domain) is a Superfamily 2, 3'-5' helicase involved in DNA repair.
• HELQ interacts with Replication Protein A (RPA) and is a potential therapeutic target for cancer.
• R-loops are nucleic acid structures formed by DNA:RNA hybrids that can compromise genome stability.

Purpose of the Study:

• To investigate a novel role for HELQ in the resolution of R-loops.
• To elucidate the mechanism of HELQ recruitment and activity at R-loops.
• To identify potential protein interactions coordinating HELQ function in R-loop metabolism.

Main Methods:

• Cell-based assays to observe HELQ localization and function.
• In vitro biochemical assays to assess HELQ ATPase/helicase activity.
• Co-immunoprecipitation and functional interaction studies with XRN2.

Main Results:

• HELQ is recruited by RPA to R-loops in cells and in vitro.
• Catalytically active HELQ resolves R-loops.
• A functional interaction between HELQ and the nuclear exoribonuclease XRN2 was identified.

Conclusions:

• HELQ plays a significant role in resolving R-loops, contributing to genome stability.
• The coordinated action of HELQ and XRN2 (nuclear 5' to 3' exoribonuclease) is crucial for R-loop metabolism.
• This study assigns a new biological function for HELQ in maintaining genome stability in metazoans.