Homologous recombination as a mechanism to recognize repetitive DNA sequences in an RNAi pathway
- Zhenyu Zhang1,3,
- Shwu-Shin Chang1,3,
- Zhenying Zhang2,
- Zhihong Xue1,
- Hanxing Zhang2,
- Shaojie Li2 and
- Yi Liu1,4
- 1Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
- 2State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, ZhongGuanCun, Beijing 100080, China
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↵3 These authors contributed equally to this work.
Abstract
Quelling is an RNAi-related phenomenon that post-transcriptionally silences repetitive DNA and transposons in Neurospora. We previously identified a type of DNA damage-induced small RNA called qiRNA that originates from ribosomal DNA. To understand how small RNAs are generated from repetitive DNA, we carried out a genetic screen to identify genes required for qiRNA biogenesis. Factors directly involved in homologous recombination (HR) and chromatin remodeling factors required for HR are essential for qiRNA production. HR is also required for quelling, and quelling is also the result of DNA damage, indicating that quelling and qiRNA production share a common mechanism. Together, our results suggest that DNA damage-triggered HR-based recombination allows the RNAi pathway to recognize repetitive DNA to produce small RNA.
Keywords
Footnotes
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↵4 Corresponding author
E-mail yi.liu{at}utsouthwestern.edu
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Supplemental material is available for this article.
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Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.209494.112.
- Received November 2, 2012.
- Accepted December 21, 2012.
- Copyright © 2013 by Cold Spring Harbor Laboratory Press
