title: RNase L restricts the mobility of engineered retrotransposons in cultured human cells.
abstract: Retrotransposons are mobile genetic elements, and their mobility can lead to genomic instability. Retrotransposon insertions are associated with a diverse range of sporadic diseases, including cancer. Thus, it is not a surprise that multiple host defense mechanisms suppress retrotransposition. The 2',5'-oligoadenylate (2-5A) synthetase (OAS)-RNase L system is a mechanism for restricting viral infections during the interferon antiviral response. Here, we investigated a potential role for the OAS-RNase L system in the restriction of retrotransposons. Expression of wild type (WT) and a constitutively active form of RNase L (NΔ385), but not a catalytically inactive RNase L mutant (R667A), impaired the mobility of engineered human LINE-1 (L1) and mouse intracisternal A-type particle retrotransposons in cultured human cells. Furthermore, WT RNase L, but not an inactive RNase L mutant (R667A), reduced L1 RNA levels and subsequent expression of the L1-encoded proteins (ORF1p and ORF2p). Consistently, confocal immunofluorescent microscopy demonstrated that WT RNase L, but not RNase L R667A, prevented formation of L1 cytoplasmic foci. Finally, siRNA-mediated depletion of endogenous RNase L in a human ovarian cancer cell line (Hey1b) increased the levels of L1 retrotransposition by ∼2-fold. Together, these data suggest that RNase L might function as a suppressor of structurally distinct retrotransposons.
authors.affiliation: Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, OH, 44195, USA, Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA, Department of Human Genetics, Ann Arbor, MI 48109, USA, Cellular and Molecular Biology Program, Ann Arbor, MI 48109, USA, Department of Internal Medicine, Ann Arbor, MI 48109, USA and Howard Hughes Medical Institute, University of Michigan Medical School, Ann Arbor, Michigan, 48109, USA.
authors.forename: Ao
authors.initials: A
authors.lastname: Zhang
authors.forename: Beihua
authors.initials: B
authors.lastname: Dong
authors.forename: Aurélien J
authors.initials: AJ
authors.lastname: Doucet
authors.forename: John B
authors.initials: JB
authors.lastname: Moldovan
authors.forename: John V
authors.initials: JV
authors.lastname: Moran
authors.forename: Robert H
authors.initials: RH
authors.lastname: Silverman
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004722:Endoribonucleases / Q000378:metabolism*; D007426:Genes, Intracisternal A-Particle; D006367:HeLa Cells; D006801:Humans; D020084:Long Interspersed Nucleotide Elements; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D014764:Viral Proteins; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease