Previous Article | Next Article 
Molecular and Cellular Biology, December 2006, p. 8731-8742, Vol. 26, No. 23
0270-7306/06/$08.00+0 doi:10.1128/MCB.01430-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.
Induction of Gene Silencing by Hairpin RNA Expression in Tetrahymena thermophila Reveals a Second Small RNA Pathway
Rachel A. Howard-Till1,2 and
Meng-Chao Yao1,3*
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle,
Washington 98109,1
Molecular and Cellular Biology Program, University of Washington, Seattle, Washington
98195,2
Institute of Molecular Biology, Academia Sinica, Taipei 11529,
Taiwan3
Received 2 August 2006/
Returned for modification 24 August 2006/
Accepted 18 September 2006
Unlike in other eukaryotes, in which it causes gene silencing, RNA
interference (RNAi) has been linked to programmed DNA deletion in the
ciliate Tetrahymena thermophila. Here we have developed an
efficient method to inducibly express double-stranded RNA hairpins and
demonstrated that they cause gene silencing through targeted mRNA
degradation in all phases of the life cycle, including growth,
starvation, and mating. This technique offers a new tool for gene
silencing in this model organism. Induction of RNA hairpins causes
dramatic upregulation of Dicer and Argonaute family genes, revealing a
system capable of rapidly responding to double-stranded RNA. These
hairpins are processed into 23- to 24-nucleotide (nt) small RNAs, which
are distinctly different from the 28- to 30-nt small RNAs known to be
associated with DNA deletion. Thus, two different small RNA pathways
appear to be responsible for gene silencing and DNA deletion.
Surprisingly, expression of the RNA hairpin also causes targeted DNA
deletion during conjugation, although at low efficiencies, which
suggests a possible crossover of these two molecular
paths.
* Corresponding author. Mailing address: Division of Basic Sciences, Fred Hutchinson
Cancer Research Center, 1100 Fairview Ave N., P.O. Box 19024, Seattle, WA 98109. Phone: (206) 667-5005. Fax: (206) 667-6526. E-mail:
mcyao{at}fhcrc.org.
Published ahead of print on 25 September 2006.
Molecular and Cellular Biology, December 2006, p. 8731-8742, Vol. 26, No. 23
0270-7306/06/$08.00+0 doi:10.1128/MCB.01430-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Couvillion, M. T., Lee, S. R., Hogstad, B., Malone, C. D., Tonkin, L. A., Sachidanandam, R., Hannon, G. J., Collins, K.
(2009). Sequence, biogenesis, and function of diverse small RNA classes bound to the Piwi family proteins of Tetrahymena thermophila. Genes Dev.
23: 2016-2032
[Abstract]
[Full Text]
-
Lepere, G., Nowacki, M., Serrano, V., Gout, J.-F., Guglielmi, G., Duharcourt, S., Meyer, E.
(2009). Silencing-associated and meiosis-specific small RNA pathways in Paramecium tetraurelia. Nucleic Acids Res
37: 903-915
[Abstract]
[Full Text]
-
Lepere, G., Betermier, M., Meyer, E., Duharcourt, S.
(2008). Maternal noncoding transcripts antagonize the targeting of DNA elimination by scanRNAs in Paramecium tetraurelia. Genes Dev.
22: 1501-1512
[Abstract]
[Full Text]
-
Barchetta, S., La Terza, A., Ballarini, P., Pucciarelli, S., Miceli, C.
(2008). Combination of Two Regulatory Elements in the Tetrahymena thermophila HSP70-1 Gene Controls Heat Shock Activation. Eukaryot Cell
7: 379-386
[Abstract]
[Full Text]
-
Robinson, T., Katz, L. A.
(2007). Non-Mendelian Inheritance of Paralogs of 2 Cytoskeletal Genes in the Ciliate Chilodonella uncinata. Mol Biol Evol
24: 2495-2503
[Abstract]
[Full Text]
-
Howard-Till, R. A., Yao, M.-C.
(2007). Tudor Nuclease Genes and Programmed DNA Rearrangements in Tetrahymena thermophila. Eukaryot Cell
6: 1795-1804
[Abstract]
[Full Text]
-
Shi, H., Tschudi, C., Ullu, E.
(2007). Depletion of newly synthesized Argonaute1 impairs the RNAi response in Trypanosoma brucei. RNA
13: 1132-1139
[Abstract]
[Full Text]
-
Liu, Y., Taverna, S. D., Muratore, T. L., Shabanowitz, J., Hunt, D. F., Allis, C. D.
(2007). RNAi-dependent H3K27 methylation is required for heterochromatin formation and DNA elimination in Tetrahymena. Genes Dev.
21: 1530-1545
[Abstract]
[Full Text]