title: Male germ cell-specific knockout of cholesterogenic cytochrome P450 lanosterol 14α-demethylase (Cyp51).
abstract: Cytochrome P450 lanosterol 14α-demethylase (CYP51) and its products, meiosis-activating sterols (MASs), were hypothesized by previous in vitro studies to have an important role in regulating meiosis and reproduction. To test this in vivo, we generated a conditional male germ cell-specific knockout of the gene Cyp51 in the mouse. High excision efficiency of Cyp51 allele in germ cells resulted in 85-89% downregulation of Cyp51 mRNA and protein levels in germ cells. Quantitative metabolic profiling revealed significantly higher levels of CYP51 substrates lanosterol and 24,25-dihydrolanosterol and substantially diminished levels of MAS, the immediate products of CYP51. However, germ cell-specific ablation of Cyp51, leading to lack of MAS, did not affect testicular morphology, daily sperm production, or reproductive performance in males. It is plausible that due to the similar structures of cholesterol intermediates, previously proposed biological function of MAS in meiosis progression can be replaced by some other yet-unidentified functionally redundant lipid molecule(s). Our results using the germ cell-specific knockout model provide first in vivo evidence that the de novo synthesis of MAS and cholesterol in male germ cells is most likely not essential for spermatogenesis and reproduction and that MASs, originating from germ cells, do not cell-autonomously regulate spermatogenesis and fertility.
authors.affiliation: Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia.
authors.forename: Rok
authors.initials: R
authors.lastname: Keber
authors.affiliation: Centre for Functional Genomics and Bio-Chips, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Jure
authors.initials: J
authors.lastname: Ačimovič
authors.affiliation: Center for Animal Genomics, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Gregor
authors.initials: G
authors.lastname: Majdič
authors.affiliation: Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Helena
authors.initials: H
authors.lastname: Motaln
authors.affiliation: Centre for Functional Genomics and Bio-Chips, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Damjana
authors.initials: D
authors.lastname: Rozman
authors.affiliation: Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia; National Institute of Chemistry, Laboratory for Biotechnology, Ljubljana, Slovenia. Electronic address: simon.horvat@bf.uni-lj.si.
authors.forename: Simon
authors.initials: S
authors.lastname: Horvat
mesh_terms: D000818:Animals; D007810:Lanosterol / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D008297:Male; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000201:enzymology*; D058886:Sterol 14-Demethylase / Q000235:genetics / Q000378:metabolism*
chemical_list: D007810:Lanosterol; C015316:lanostenol; C548415:Cyp51 protein, mouse; D058886:Sterol 14-Demethylase
keywords: meiosis-activating sterol; spermatogenesis; sterol intermediate