Evidence for multiple,distinct ADAR-containing complexes in Xenopus laevis |
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Authors: | Caterina T.H. Schweidenback Amy B. Emerman Ashwini Jambhekar Michael D. Blower |
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Affiliation: | 1.Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA;2.Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA |
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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. |
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Keywords: | A-to-I editing RNA editing dsRNA RNP |
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