@article{da9d192c0f5c4f3b80eb3978a8133214,
title = "Replication Stress Induces Global Chromosome Breakage in the Fragile X Genome",
abstract = "Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by mutations in the FMR1 gene and deficiency of a functional FMRP protein. FMRP is known as a translation repressor whose nuclear function is not understood. We investigated the global impact on genome stability due to FMRP loss. Using Break-seq, we map spontaneous and replication stress-induced DNA double-strand breaks (DSBs) in an FXS patient-derived cell line. We report that the genomes of FXS cells are inherently unstable and accumulate twice as many DSBs as those from an unaffected control. We demonstrate that replication stress-induced DSBs in FXS cells colocalize with R-loop forming sequences. Exogenously expressed FMRP in FXS fibroblasts ameliorates DSB formation. FMRP, not the I304N mutant, abates R-loop-induced DSBs during programmed replication-transcription conflict. These results suggest that FMRP is a genome maintenance protein that prevents R-loop accumulation. Our study provides insights into the etiological basis for FXS. Chakraborty et al. report a genome-wide increase of DNA double-strand breaks in fragile X syndrome patient cells and suggest that FMRP functions in the R-loop pathway to prevent genome instability induced by DNA replication-transcription conflicts.",
keywords = "DNA double-strand breaks, DNA replication stress, DSB, FMRP, FXS, I304N, R-loops, chromosome fragile sites, fragile X syndrome, genome instability",
author = "Arijita Chakraborty and Piroon Jenjaroenpun and Jing Li and {El Hilali}, Sami and Andrew McCulley and Brian Haarer and Hoffman, {Elizabeth A.} and Aimee Belak and Audrey Thorland and Heidi Hehnly and Carl Schildkraut and Chen, {Chun long} and Kuznetsov, {Vladimir A.} and Wenyi Feng",
note = "Funding Information: We thank V. Van Steenkist for systems support; Drs. L. Kotula, C. Dobkin, B. Howell, and A. Aguilera for antibodies and plasmids; and Drs. L. Kotula, F. Middleton, P. Kane, and T. Wongsurawat for helpful discussions. We also thank the staff at SUNY Upstate Flow Cytometry Core and the University at Buffalo Genomics Core for flow sorting and HiSeq sequencing, respectively. This work was supported by the National Institutes of Health grants 5R00GM08137805 and 5R01-GM118799 to W.F.; the Department of Defense CDMRP Discovery Award W81XWH-15-1-0204 to W.F.; institutional support from A ∗ STAR and a SUNY EMPIRE scholar grant to V.A.K.; the Department of Defense grant PC160083 to H.H.; the I. Curie YPI program , the ATIP-Avenir program from CNRS and Plan Cancer from INSERM , and the Agence Nationale pour la Recherche (ANR) to C.L.C.; and the National Institutes of Health grant 5R01-GM045751 to C.S. Funding Information: We thank V. Van Steenkist for systems support; Drs. L. Kotula, C. Dobkin, B. Howell, and A. Aguilera for antibodies and plasmids; and Drs. L. Kotula, F. Middleton, P. Kane, and T. Wongsurawat for helpful discussions. We also thank the staff at SUNY Upstate Flow Cytometry Core and the University at Buffalo Genomics Core for flow sorting and HiSeq sequencing, respectively. This work was supported by the National Institutes of Health grants 5R00GM08137805 and 5R01-GM118799 to W.F.; the Department of Defense CDMRP Discovery Award W81XWH-15-1-0204 to W.F.; institutional support from A?STAR and a SUNY EMPIRE scholar grant to V.A.K.; the Department of Defense grant PC160083 to H.H.; the I. Curie YPI program, the ATIP-Avenir program from CNRS and Plan Cancer from INSERM, and the Agence Nationale pour la Recherche (ANR) to C.L.C.; and the National Institutes of Health grant 5R01-GM045751 to C.S. A.C. and W.F. conceived the study and designed the experiments. A.C. A.M. E.A.H. B.H. A.B. and W.F. performed the Break-seq experiments. A.C. J.L. and H.H. performed and analyzed the immunostaining experiments. A.C. and A.T. performed the recombination assays. A.C. performed and analyzed the flow cytometry. P.J. V.A.K. S.E.H. C.L.C. and W.F. performed the computational analyses. C.S. provided intellectual contributions over many discussions on fragile sites. A.C. and W.F. wrote the manuscript with input from all of the authors. The authors declare no competing interests. Publisher Copyright: {\textcopyright} 2020",
year = "2020",
month = sep,
day = "22",
doi = "10.1016/j.celrep.2020.108179",
language = "English (US)",
volume = "32",
journal = "Cell Reports",
issn = "2211-1247",
publisher = "Cell Press",
number = "12",
}