The RRM domains of PARP14 mediate replication fork degradation in BRCA2-deficient cells

Area of Science:

• Molecular Biology
• Genetics
• Cancer Research

Background:

• BRCA-deficient cells exhibit chemosensitivity due to nuclease-mediated degradation of reversed replication forks.
• PARP14 was previously identified as a regulator of MRE11 recruitment to reversed replication forks, promoting their degradation and genomic instability.

Purpose of the Study:

• To investigate the mechanism by which PARP14 binds to nascent DNA at reversed replication forks.
• To determine the role of PARP14's RNA Recognition Motifs (RRMs) in MRE11 recruitment and DNA degradation.

Main Methods:

• Recruitment assays to identify PARP14 binding to nascent DNA.
• Functional assays to assess the necessity of RRM domains for MRE11 recruitment and DNA degradation.
• Analysis of replication stress-induced double-strand break formation.

Main Results:

• PARP14 is recruited to nascent DNA at reversed replication forks via its RRM domains in BRCA-deficient cells.
• The RRM domains are essential for recruiting MRE11 to reversed forks, promoting nascent strand degradation at stalled replication forks in BRCA2-deficient cells.
• These RRM domains are critical for replication stress-induced double-strand break formation.

Conclusions:

• PARP14's RRM domains mediate its binding to nascent DNA at reversed replication forks.
• This interaction is crucial for MRE11 recruitment, nascent strand degradation, and subsequent double-strand break formation in BRCA-deficient cells.
• The findings enhance the understanding of nuclease engagement at stalled forks and its role in maintaining genomic stability.