title: Evidence for multiple, distinct ADAR-containing complexes in Xenopus laevis.
abstract: ADAR (adenosine deaminase acting on RNA) is an RNA-editing enzyme present in most metazoans that converts adenosines in double-stranded RNA targets into inosines. Although the RNA targets of ADAR-mediated editing have been extensively cataloged, our understanding of the cellular function of such editing remains incomplete. We report that long, double-stranded RNA added to Xenopus laevis egg extract is incorporated into an ADAR-containing complex whose protein components resemble those of stress granules. This complex localizes to microtubules, as assayed by accumulation on meiotic spindles. We observe that the length of a double-stranded RNA influences its incorporation into the microtubule-localized complex. ADAR forms a similar complex with endogenous RNA, but the endogenous complex fails to localize to microtubules. In addition, we characterize the endogenous, ADAR-associated RNAs and discover that they are enriched for transcripts encoding transcriptional regulators, zinc-finger proteins, and components of the secretory pathway. Interestingly, association with ADAR correlates with previously reported translational repression in early embryonic development. This work demonstrates that ADAR is a component of two, distinct ribonucleoprotein complexes that contain different types of RNAs and exhibit diverse cellular localization patterns. Our findings offer new insight into the potential cellular functions of ADAR.
authors.affiliation: Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Caterina T H
authors.initials: CT
authors.lastname: Schweidenback
authors.affiliation: Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Amy B
authors.initials: AB
authors.lastname: Emerman
authors.affiliation: Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Ashwini
authors.initials: A
authors.lastname: Jambhekar
authors.affiliation: Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA blower@molbio.mgh.harvard.edu.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Blower
mesh_terms: D000243:Adenosine Deaminase / Q000378:metabolism*; D000818:Animals; D009865:Oocytes / Q000201:enzymology; D034443:RNA Transport; D012330:RNA, Double-Stranded / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D012330:RNA, Double-Stranded; D012261:Ribonucleoproteins; D029867:Xenopus Proteins; D000243:Adenosine Deaminase
keywords: A-to-I editing; RNA editing; RNP; dsRNA