Cell-type specific role of the RNA-binding protein, NONO, in the DNA double-strand break response in the mouse testes

• Type of Material: Article
• Authors: Shuyi Li, Emory University; Feng-jue Shu, Emory University; Zhentian Li, Emory University; Lahcen Jaafar, Emory University; Shourong Zhao, Columbus Pathology; William Dynan, Emory University
• Language: English
• Date: 2017-03-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Elsevier B.V.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.dnarep.2017.02.002
• Title of Journal or Parent Work: DNA Repair
• ISSN: 1568-7864
• Volume: 51
• Start Page: 70
• End Page: 78
• Grant/Funding Information: This work was supported by a USPHS R01 grant, CA98239,a US Department of Energy grant, DE-SC0002343, to WSD, and by the Emory University School of Medicine.; The JEOL JEM-1400 electron microscope was acquired with USPHS S10 grant (RR025679 01).
• Keywords: Ionizing radiation; Testes; Genetics & Heredity; Toxicology; Life Sciences & Biomedicine; PSF; GENE-REGULATION; SPERMATOGENESIS; NHEJ; NONO; P54(NRB); DAMAGE RESPONSE; Double-strand break repair; SPLICING-FACTOR; Science & Technology; CONNEXIN-43; COMPLEX; Knockout mouse; REPAIR; TRANSCRIPTION
• Research Categories: Biology, Genetics; Health Sciences, Oncology; Biology, Cell

Abstract

The tandem RNA recognition motif protein, NONO, was previously identified as a candidate DNA double-strand break (DSB) repair factor in a biochemical screen for proteins with end-joining stimulatory activity. Subsequent work showed that NONO and its binding partner, SFPQ, have many of the properties expected for bona fide repair factors in cell-based assays. Their contribution to the DNA damage response in intact tissue in vivo has not, however, been demonstrated. Here we compare DNA damage sensitivity in the testes of wild-type mice versus mice bearing a null allele of the NONO homologue (Nono gt ). In wild-type mice, NONO protein was present in Sertoli, peritubular myoid, and interstitial cells, with an increase in expression following induction of DNA damage. As expected for the product of an X-linked gene, NONO was not detected in germ cells. The Nono gt/0 mice had at most a mild testis developmental phenotype in the absence of genotoxic stress. However, following irradiation at sublethal, 2–4 Gy doses, Nono gt/0 mice displayed a number of indicators of radiosensitivity as compared to their wild-type counterparts. These included higher levels of persistent DSB repair foci, increased numbers of apoptotic cells in the seminiferous tubules, and partial degeneration of the blood-testis barrier. There was also an almost complete loss of germ cells at later times following irradiation, evidently arising as an indirect effect reflecting loss of stromal support. Results demonstrate a role for NONO protein in protection against direct and indirect biological effects of ionizing radiation in the whole animal.