title: Piwi proteins and piRNAs in mammalian oocytes and early embryos.
abstract: Germ cells of most animals critically depend on piRNAs and Piwi proteins. Surprisingly, piRNAs in mouse oocytes are relatively rare and dispensable. We present compelling evidence for strong Piwi and piRNA expression in oocytes of other mammals. Human fetal oocytes express PIWIL2 and transposon-enriched piRNAs. Oocytes in adult human ovary express PIWIL1 and PIWIL2, whereas those in bovine ovary only express PIWIL1. In human, macaque, and bovine ovaries, we find piRNAs that resemble testis-borne pachytene piRNAs. Isolated bovine follicular oocytes were shown to contain abundant, relatively short piRNAs that preferentially target transposable elements. Using label-free quantitative proteome analysis, we show that these maturing oocytes strongly and specifically express the PIWIL3 protein, alongside other, known piRNA-pathway components. A piRNA pool is still present in early bovine embryos, revealing a potential impact of piRNAs on mammalian embryogenesis. Our results reveal that there are highly dynamic piRNA pathways in mammalian oocytes and early embryos.
authors.affiliation: Biology of Non-coding RNA Group, Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany.
authors.forename: Elke F
authors.initials: EF
authors.lastname: Roovers
authors.affiliation: Johannes Gutenberg-University Mainz, Institute of Anthropology, Anselm-Franz-von-Bentzel-Weg 7, 55128 Mainz, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Rosenkranz
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, the Netherlands.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Mahdipour
authors.affiliation: Genomics Core Facility, Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany.
authors.forename: Chung-Ting
authors.initials: CT
authors.lastname: Han
authors.affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Einthovenweg 20, 2333 ZA Leiden, the Netherlands.
authors.forename: Nannan
authors.initials: N
authors.lastname: He
authors.affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Einthovenweg 20, 2333 ZA Leiden, the Netherlands.
authors.forename: Susana M
authors.initials: SM
authors.lastname: Chuva de Sousa Lopes
authors.affiliation: Department of Gynaecology, Leiden University Medical Center, Albinusdreef 2, 2300RC Leiden, the Netherlands.
authors.forename: Lucette A J
authors.initials: LA
authors.lastname: van der Westerlaken
authors.affiliation: Johannes Gutenberg-University Mainz, Institute of Anthropology, Anselm-Franz-von-Bentzel-Weg 7, 55128 Mainz, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Zischler
authors.affiliation: Quantitative Proteomics Group, Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Butter
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, the Netherlands.
authors.forename: Bernard A J
authors.initials: BA
authors.lastname: Roelen
authors.affiliation: Biology of Non-coding RNA Group, Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany. Electronic address: r.ketting@imb.de.
authors.forename: René F
authors.initials: RF
authors.lastname: Ketting
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism*; D002417:Cattle; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005854:Germ Cells / Q000378:metabolism; D006801:Humans; D008297:Male; D009865:Oocytes / Q000166:cytology*; D010053:Ovary / Q000196:embryology* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D013737:Testis / Q000196:embryology* / Q000378:metabolism
chemical_list: D060565:Argonaute Proteins; C421088:PIWIL1 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering