Two classes of endogenous small RNAs in Tetrahymena thermophila

  1. Suzanne R. Lee and
  2. Kathleen Collins1
  1. Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720-3204, USA

Abstract

Endogenous small RNAs function in RNA interference (RNAi) pathways to guide RNA cleavage, translational repression, or methylation of DNA or chromatin. In Tetrahymena thermophila, developmentally regulated DNA elimination is governed by an RNAi mechanism involving ∼27–30-nucleotide (nt) RNAs. Here we characterize the sequence features of the ∼27–30-nt RNAs and a ∼23–24-nt RNA class representing a second RNAi pathway. The ∼23–24-nt RNAs accumulate strain-specifically manner and map to the genome in clusters that are antisense to predicted genes. These findings reveal the existence of distinct endogenous RNAi pathways in the unicellular T. thermophila, a complexity previously demonstrated only in multicellular organisms.

Keywords

Footnotes

  • Supplemental material is available at http://www.genesdev.org.

  • Article published online ahead of print. Article and publication date are at http://www.genesdev.org/cgi/doi/10.1101/gad.1377006.

  • 1 Corresponding author.

    1 E-MAIL kcollins{at}berkeley.edu; FAX (510) 643-6334.

    • Accepted November 2, 2005.
    • Received September 21, 2005.
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