title: Expression of variant ribosomal RNA genes in mouse oocytes and preimplantation embryos.
abstract: Ribosomal DNA (rDNA) is not composed of multiple copies of identical transcription units, as commonly believed, but rather of at least seven rDNA variant subtypes that are expressed in somatic cells. This finding raises the possibility that ribosome function may be modulated as proposed by the ribosome filter hypothesis. We report here that mouse oocytes and preimplantation embryos express all the rDNA variants except variant V and that there is no marked developmental change in the qualitative pattern of variant expression. The maternal and embryonic ribosome pools are therefore quite similar, minimizing the likelihood that developmental changes in composition of the ribosome population are critical for preimplantation development.
authors.affiliation: Department of Biology, University of Pennsylvania, 433 South University Ave., Philadelphia, PA 19104, USA.
authors.forename: Motomasa
authors.initials: M
authors.lastname: Ihara
authors.forename: Hung
authors.initials: H
authors.lastname: Tseng
authors.forename: Richard M
authors.initials: RM
authors.lastname: Schultz
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology* / Q000378:metabolism; D004275:DNA, Ribosomal / Q000235:genetics; D004477:Ectogenesis; D005260:Female; D018507:Gene Expression Regulation, Developmental; D014644:Genetic Variation; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012335:RNA, Ribosomal / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012270:Ribosomes / Q000235:genetics* / Q000502:physiology
chemical_list: D004275:DNA, Ribosomal; D012335:RNA, Ribosomal