Abstract
Mutations that enhance the response to double-stranded RNA (dsRNA) have revealed components of the RNA interference (RNAi) pathway or related small RNA pathways. To explore these small RNA pathways, we screened for Caenorhabditis elegans mutants displaying an enhanced response to exogenous dsRNAs. Here we describe the isolation of mutations in two adjacent, divergently transcribed open reading frames (eri-6 and eri-7) that fail to complement. eri-6 and eri-7 produce separate pre-messenger RNAs (pre-mRNAs) that are trans-spliced to form a functional mRNA, eri-6/7. Trans-splicing of eri-6/7 is mediated by a direct repeat that flanks the eri-6 gene. Adenosine to inosine editing within untranslated regions of eri-6 and eri-7 pre-mRNAs reveals a double-stranded pre-mRNA intermediate, forming in the nucleus before splicing occurs. The ERI-6/7 protein is a superfamily I helicase that both negatively regulates the exogenous RNAi pathway and functions in an endogenous RNAi pathway.
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Acknowledgements
We thank: S. Kennedy for advice and initiating the enhanced RNAi screen; M. Finney for advice on advanced PCR; C. Zhang for mg441 Eri characterization; Y. Kohara, D. Thierry-Mieg and J. Thierry-Mieg for EST sequences and clones; the Mitani laboratory for deletion strains; the Caenorhabditis Genetics Center for strains; Ruvkun laboratory members for reading the manuscript and many discussions; the laboratories of J. Kaplan and F. Ausubel for discussions; and the Leukemia and Lymphoma Society, and EMBO for funding to S.E.J.F.
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Fischer, S., Butler, M., Pan, Q. et al. Trans-splicing in C. elegans generates the negative RNAi regulator ERI-6/7. Nature 455, 491–496 (2008). https://doi.org/10.1038/nature07274
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DOI: https://doi.org/10.1038/nature07274
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