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Journal of Nucleic Acids
Volume 2013, Article ID 629218, 7 pages
Research Article

R-Loop Formation In Trans at an AGGAG Repeat

1Department of Life Science and Research Center for Life Science, Rikkyo (St. Paul’s) University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
2Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kami-Kitazawa, Setagaya-ku, Tokyo 156-8506, Japan

Received 29 May 2013; Accepted 25 July 2013

Academic Editor: Luis A. Marky

Copyright © 2013 Kazuya Toriumi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Formation of RNA-DNA hybrid, or R-loop, was studied in vitro by transcribing an AGGAG repeat with T7 RNA polymerase. When ribonuclease T1 was present, R-loop formation in cis was diminished, indicating that the transcript was separated from the template and reassociated with it. The transcript was found to form an R-loop in trans with DNA comprising the AGGAG repeat, when the DNA was supercoiled. Results of chemical modification indicated that the duplex opened at the AGGAG repeat under negative supercoiling.