Abstract
DNA double-strand breaks (DSBs) at RNA polymerase II (RNAPII) transcribed genes lead to inhibition of transcription. The DNA-dependent protein kinase (DNA-PK) complex plays a pivotal role in transcription inhibition at DSBs by stimulating proteasome-dependent eviction of RNAPII at these lesions. How DNA-PK triggers RNAPII eviction to inhibit transcription at DSBs remains unclear. Here we show that the HECT E3 ubiquitin ligase WWP2 associates with components of the DNA-PK and RNAPII complexes and is recruited to DSBs at RNAPII transcribed genes. In response to DSBs, WWP2 targets the RNAPII subunit RPB1 for K48-linked ubiquitylation, thereby driving DNA-PK- and proteasome-dependent eviction of RNAPII. The lack of WWP2 or expression of nonubiquitylatable RPB1 abrogates the binding of nonhomologous end joining (NHEJ) factors, including DNA-PK and XRCC4/DNA ligase IV, and impairs DSB repair. These findings suggest that WWP2 operates in a DNA-PK-dependent shutoff circuitry for RNAPII clearance that promotes DSB repair by protecting the NHEJ machinery from collision with the transcription machinery.
Highlights
DNA double-strands breaks (DSBs) are a threat to the integrity of our genome
WWP2-depleted cells were markedly more sensitive to IR when compared with control cells, not to the same extent as cells depleted of the core nonhomologous end joining (NHEJ) factor XRCC4 (Fig. 1A)
In this study, we provide insight into the molecular events that lead to transcription silencing induced by DSBs at RNA polymerase II (RNAPII) transcribed genes
Summary
DNA double-strands breaks (DSBs) are a threat to the integrity of our genome. If left unrepaired or repaired inaccurately, they can lead to chromosomal rearrangements or loss of genetic information. While RNF8/RNF168 recruitment relies on ATMdependent phosphorylation of H2AX and MDC1 (Dantuma and van Attikum 2016), Ring1B is recruited through ATM-dependent phosphorylation of the superelongating complex (SEC) and the PBAF chromatin remodeling complex (Shanbhag et al 2010; Kakarougkas et al 2014; Ui et al 2015) These ATM-driven mechanisms for transcription silencing are critical for proper DSB repair through NHEJ. While NELF promotes DSB repair via both NHEJ and HR, KDM5a, ZMYND8–NuRD, and CDYL1 promote DSB repair through HR only (Gong et al 2015, 2017; Abu-Zhayia et al 2018) Together, these studies revealed that ATM and PARP1 silence transcription of genes that flank DSBs by triggering extensive chromatin remodeling around the damage, thereby promoting efficient repair by NHEJ and HR. WWP2 acts in a DNA-PKcs-dependent manner to target RNAPII for ubiquitylation and subsequent degradation by the proteasome, thereby promoting transcription repression and DSB repair by cNHEJ
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
