title: The small RNA content of human sperm reveals pseudogene-derived piRNAs complementary to protein-coding genes.
abstract: At the end of mammalian sperm development, sperm cells expel most of their cytoplasm and dispose of the majority of their RNA. Yet, hundreds of RNA molecules remain in mature sperm. The biological significance of the vast majority of these molecules is unclear. To better understand the processes that generate sperm small RNAs and what roles they may have, we sequenced and characterized the small RNA content of sperm samples from two human fertile individuals. We detected 182 microRNAs, some of which are highly abundant. The most abundant microRNA in sperm is miR-1246 with predicted targets among sperm-specific genes. The most abundant class of small noncoding RNAs in sperm are PIWI-interacting RNAs (piRNAs). Surprisingly, we found that human sperm cells contain piRNAs processed from pseudogenes. Clusters of piRNAs from human testes contain pseudogenes transcribed in the antisense strand and processed into small RNAs. Several human protein-coding genes contain antisense predicted targets of pseudogene-derived piRNAs in the male germline and these piRNAs are still found in mature sperm. Our study provides the most extensive data set and annotation of human sperm small RNAs to date and is a resource for further functional studies on the roles of sperm small RNAs. In addition, we propose that some of the pseudogene-derived human piRNAs may regulate expression of their parent gene in the male germline.
authors.affiliation: Institute of Predictive and Personalized Medicine of Cancer (IMPPC), Can Ruti Campus, Badalona, Barcelona 08916, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Pantano
authors.affiliation: Genetics Unit, Department of Physiological Sciences, University of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Biochemistry and Molecular Genetics Service, Hospital Clinic, 08036 Barcelona, Spain.
authors.forename: Meritxell
authors.initials: M
authors.lastname: Jodar
authors.affiliation: Center for non-coding RNA in Technology and Health (RTH), University of Copenhagen, DK-2200 Copenhagen, Denmark Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, Faculty of Health Science, University of Copenhagen, DK-2200 Copenhagen, Denmark.
authors.forename: Mads
authors.initials: M
authors.lastname: Bak
authors.affiliation: Andrology Unit, Institut Clínic de Ginecologia, Obstetricia i Neonatologia, Hospital Clínic, 08036 Barcelona, Spain.
authors.forename: Josep Lluís
authors.initials: JL
authors.lastname: Ballescà
authors.affiliation: Center for non-coding RNA in Technology and Health (RTH), University of Copenhagen, DK-2200 Copenhagen, Denmark Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, Faculty of Health Science, University of Copenhagen, DK-2200 Copenhagen, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Tommerup
authors.affiliation: Genetics Unit, Department of Physiological Sciences, University of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Biochemistry and Molecular Genetics Service, Hospital Clinic, 08036 Barcelona, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Oliva
authors.affiliation: Institute of Predictive and Personalized Medicine of Cancer (IMPPC), Can Ruti Campus, Badalona, Barcelona 08916, Spain Josep Carreras Leukaemia Research Institute (IJC), ICO-Hospital GermansTrias i Pujol, Badalona, Barcelona 08916, Spain.
authors.forename: Tanya
authors.initials: T
authors.lastname: Vavouri
mesh_terms: D006801:Humans; D020084:Long Interspersed Nucleotide Elements; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000378:metabolism; D011544:Pseudogenes; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism*; D017423:Sequence Analysis, RNA / Q000379:methods; D013094:Spermatozoa / Q000378:metabolism*; D013737:Testis / Q000378:metabolism
chemical_list: C577700:MIRN1246 microRNA, human; D035683:MicroRNAs; D011506:Proteins; D034741:RNA, Small Interfering
keywords: PIWI; RNA; microRNA; piRNA; pseudogene; sperm