title: The enigmatic meiotic dense body and its newly discovered component, SCML1, are dispensable for fertility and gametogenesis in mice.
abstract: Meiosis is a critical phase in the life cycle of sexually reproducing organisms. Chromosome numbers are halved during meiosis, which requires meiosis-specific modification of chromosome behaviour. Furthermore, suppression of transposons is particularly important during meiosis to allow the transmission of undamaged genomic information between generations. Correspondingly, specialized genome defence mechanisms and nuclear structures characterize the germ line during meiosis. Survival of mammalian spermatocytes requires that the sex chromosomes form a distinct silenced chromatin domain, called the sex body. An enigmatic spherical DNA-negative structure, called the meiotic dense body, forms in association with the sex body. The dense body contains small non-coding RNAs including microRNAs and PIWI-associated RNAs. These observations gave rise to speculations that the dense body may be involved in sex body formation and or small non-coding RNA functions, e.g. the silencing of transposons. Nevertheless, the function of the dense body has remained mysterious because no protein essential for dense body formation has been reported yet. We discovered that the polycomb-related sex comb on midleg-like 1 (SCML1) is a meiosis-specific protein and is an essential component of the meiotic dense body. Despite abolished dense body formation, Scml1-deficient mice are fertile and proficient in sex body formation, transposon silencing and in timely progression through meiosis and gametogenesis. Thus, we conclude that dense body formation is not an essential component of the gametogenetic program in the mammalian germ line.
authors.affiliation: Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Fiedlerstrasse 42, 01307, Dresden, Germany.
authors.forename: Frantzeskos
authors.initials: F
authors.lastname: Papanikos
authors.affiliation: Biotechnology Center of the TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Daniel
authors.affiliation: Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands.
authors.forename: Angelique
authors.initials: A
authors.lastname: Goercharn-Ramlal
authors.affiliation: DFG Center for Regenerative Therapies, Dresden (CRTD), Technische Universität Dresden, Dresden, 01307, Germany.
authors.forename: Ji-Feng
authors.initials: JF
authors.lastname: Fei
authors.affiliation: DFG Center for Regenerative Therapies, Dresden (CRTD), Technische Universität Dresden, Dresden, 01307, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kurth
authors.affiliation: Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Fiedlerstrasse 42, 01307, Dresden, Germany.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Wojtasz
authors.affiliation: Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Fiedlerstrasse 42, 01307, Dresden, Germany.
authors.forename: Ihsan
authors.initials: I
authors.lastname: Dereli
authors.affiliation: Biotechnology Center of the TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany.
authors.forename: Jun
authors.initials: J
authors.lastname: Fu
authors.affiliation: Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Penninger
authors.affiliation: Max Planck Institute of Biochemistry, Martinsried, Germany.
authors.forename: Bianca
authors.initials: B
authors.lastname: Habermann
authors.affiliation: Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
authors.forename: Azim
authors.initials: A
authors.lastname: Surani
authors.affiliation: Biotechnology Center of the TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany.
authors.forename: A Francis
authors.initials: AF
authors.lastname: Stewart
authors.affiliation: Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Fiedlerstrasse 42, 01307, Dresden, Germany. attila.toth@mailbox.tu-dresden.de.
authors.forename: Attila
authors.initials: A
authors.lastname: Toth
mesh_terms: D000818:Animals; D005260:Female; D005298:Fertility; D005718:Gametogenesis; D005854:Germ Cells / Q000166:cytology* / Q000378:metabolism; D008297:Male; D008540:Meiosis; D051379:Mice / Q000235:genetics / Q000378:metabolism*; D063146:Polycomb-Group Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D063146:Polycomb-Group Proteins; C000626242:SCML1 protein, mouse
keywords: Dense body; Meiosis; Polycomb; Transposon; piRNA