title: Roles of MIWI, MILI and PLD6 in small RNA regulation in mouse growing oocytes.
abstract: The mouse PIWI-interacting RNA (piRNA) pathway produces a class of 26-30-nucleotide (nt) small RNAs and is essential for spermatogenesis and retrotransposon repression. In oocytes, however, its regulation and function are poorly understood. In the present study, we investigated the consequences of loss of piRNA-pathway components in growing oocytes. When MILI (or PIWIL2), a PIWI family member, was depleted by gene knockout, almost all piRNAs disappeared. This severe loss of piRNA was accompanied by an increase in transcripts derived from specific retrotransposons, especially IAPs. MIWI (or PIWIL1) depletion had a smaller effect. In oocytes lacking PLD6 (or ZUCCHINI or MITOPLD), a mitochondrial nuclease/phospholipase involved in piRNA biogenesis in male germ cells, the piRNA level was decreased to 50% compared to wild-type, a phenotype much milder than that in males. Since PLD6 is essential for the creation of the 5΄ ends of primary piRNAs in males, the presence of mature piRNA in PLD6-depleted oocytes suggests the presence of compensating enzymes. Furthermore, we identified novel 21-23-nt small RNAs, termed spiRNAs, possessing a 10-nt complementarity with piRNAs, which were produced dependent on MILI and independent of DICER. Our study revealed the differences in the biogenesis and function of the piRNA pathway between sexes.
authors.affiliation: Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.|Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kabayama
authors.affiliation: Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Toh
authors.affiliation: Department of Development and Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Ami
authors.initials: A
authors.lastname: Katanaya
authors.affiliation: Division of Mammalian Development, Genetic Strains Research Center, National Institute of Genetics, Mishima 411-8540, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: Department of Development and Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Chuma
authors.affiliation: Department of Pathology, Medical school and Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Kuramochi-Miyagawa
authors.affiliation: Division of Mammalian Development, Genetic Strains Research Center, National Institute of Genetics, Mishima 411-8540, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Saga
authors.affiliation: Department of Pathology, Medical school and Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nakano
authors.affiliation: Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasaki
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism*; D049109:Cell Proliferation; D005260:Female; D005786:Gene Expression Regulation; D059014:High-Throughput Nucleotide Sequencing; D008810:Mice, Inbred C57BL; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D010053:Ovary / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D018626:Retroelements / Q000235:genetics
chemical_list: D060565:Argonaute Proteins; D024101:Mitochondrial Proteins; C448522:Piwil1 protein, mouse; C448521:Piwil2 protein, mouse; D034741:RNA, Small Interfering; D018626:Retroelements; D010739:Phospholipase D; C558126:mitoPLD protein, mouse