HELZ is a RNA-DNA helicase that resolves R loops to facilitate homologous recombination repair

R Ramona Haji-Seyed-Javadi A Allyson E. Koyen S Sandip K. Rath B Bo Wu M Matthew Z. Madden Y Yingzi Hou P Priya Kapoor-Vazirani R Roshika Roshika M Meili Aiello N Nho Cong Luong W Wei-Che Tseng F Fatmata Sesay J John S. Kim T Tony Tan S Seohyun Kim B Boya Gao B Boying S. Song A Anna M. Kenney E Erin C. Connolly L Lily Yang B Blerta Xhemalce X Xiaoxian Li J Jeffrey M. Switchenko (Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University) X Xiaofeng Yang Z Zachary S. Buchwald X Xingming Deng K Kyle M. Miller B Bing Yao L Li Lan (Department of Molecular Genetics and Microbiology, Duke University) W Weixing Zhao D David S. Yu

Abstract

Abstract R loop homeostasis is critical for DNA double-strand break (DSB) repair; however, how R loops are resolved in this context is poorly understood. Here, we define HELZ as a unique RNA-DNA helicase that resolves R loops to facilitate homologous recombination (HR) repair. From a synthetic lethal etoposide resistance siRNA screen, we found that HELZ depletion causes R loop-mediated hypersensitivity to DSB-inducing agents, and HELZ localizes and binds to DSBs. HELZ preferentially binds to and unwinds RNA-DNA hybrids with 5’ssRNA overhangs to promote R loop resolution genome-wide and at DSBs. Interestingly, HELZ facilitates BRCA1 recruitment to DSBs by preventing R loop accumulation, thereby promoting DNA end resection and HR to prevent R loop mediated genomic instability. In summary, we show that HELZ resolves R loops critical for HR, thereby promoting genome stability and resistance to DSB-inducing agents.

Article Details

Volume / Issue Vol. 17, Issue 1
Published July 23, 2026
ISSN 2041-1723
Publisher Nature Portfolio

Journal Info

Nature Communications

Nature Portfolio

ISSN: 2041-1723 Open Access Life Sciences

Authors (31)

R

Ramona Haji-Seyed-Javadi

A

Allyson E. Koyen

S

Sandip K. Rath

B

Bo Wu

M

Matthew Z. Madden

Y

Yingzi Hou

P

Priya Kapoor-Vazirani

R

Roshika Roshika

M

Meili Aiello

N

Nho Cong Luong

W

Wei-Che Tseng

F

Fatmata Sesay

J

John S. Kim

T

Tony Tan

S

Seohyun Kim

B

Boya Gao

B

Boying S. Song

A

Anna M. Kenney

E

Erin C. Connolly

L

Lily Yang

B

Blerta Xhemalce

X

Xiaoxian Li

J

Jeffrey M. Switchenko

Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University

X

Xiaofeng Yang

Z

Zachary S. Buchwald

X

Xingming Deng

K

Kyle M. Miller

B

Bing Yao

L

Li Lan

Department of Molecular Genetics and Microbiology, Duke University

W

Weixing Zhao

D

David S. Yu