title: Comprehensive DNA Methylation Analysis of Retrotransposons in Male Germ Cells.
abstract: De novo DNA methylation of retrotransposons is critical for silencing. Here, we use DNA methylation analysis to examine retrotransposons in mouse male germ cells. DNA methylation of long interspersed nuclear elements (LINEs) is dependent on piRNA, and younger LINEs exhibit greater piRNA dependence. In contrast, most long terminal repeat (LTR) retrotransposons produce lower levels of piRNAs and do not show significant piRNA dependence. The relationship between DNA methylation and corresponding piRNA expression of several LTR retrotransposons was reduced in Mili-null cells, but not Miwi2-null cells. These observations raise the possibility of piRNA-dependent DNA methylation without Miwi2. Therefore, it appears that the molecular mechanisms of the gene silencing of retrotransposons are more complicated than previously thought.
authors: Department of Pathology, Medical School, Osaka University, Suita, Osaka 565-0871, Japan.
authors: Ippei
authors: I
authors: Nagamori
authors: NODAI Genome Research Center, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan.
authors: Hisato
authors: H
authors: Kobayashi
authors: Department of Pathology, Medical School, Osaka University, Suita, Osaka 565-0871, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan.
authors: Yusuke
authors: Y
authors: Shiromoto
authors: Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan.
authors: Toru
authors: T
authors: Nishimura
authors: Department of Pathology, Medical School, Osaka University, Suita, Osaka 565-0871, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan.
authors: Satomi
authors: S
authors: Kuramochi-Miyagawa
authors: Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan.
authors: Tomohiro
authors: T
authors: Kono
authors: Department of Pathology, Medical School, Osaka University, Suita, Osaka 565-0871, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan. Electronic address: tnakano@patho.med.osaka-u.ac.jp.
authors: Toru
authors: T
authors: Nakano
mesh_terms: D000818:Animals; D019175:DNA Methylation; D015870:Gene Expression; D020868:Gene Silencing; D008297:Male; D008822:Mice, Transgenic; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D018626:Retroelements; D017422:Sequence Analysis, DNA; D013093:Spermatogonia / Q000502:physiology*
chemical_list: D034741:RNA, Small Interfering; D018626:Retroelements