title: Accumulation and dynamics of proteins of the MCM family during mouse oogenesis and the first embryonic cell cycle.
abstract: We describe the localization of three proteins of the minichromosome maintenance (MCM) family, Mcm2, -6 and -7 in mouse ovarian oocytes. We showed that Mcm proteins are stored in two forms: soluble and insoluble. Soluble Mcm2, -6 and -7 were uniformly distributed in the nuclei of ovarian oocytes. Insoluble Mcm2 and Mcm7 (but not Mcm6) were detected in the nuclei of resting, growing and fully-grown transcribing oocytes. In transcriptionally inactive fully-grown oocytes, Mcm2 underwent redistribution and Mcm7 disappeared. A similar effect was observed when transcription in growing oocytes was inhibited with alpha-amanitin. We postulate that in mouse oogenesis, the insoluble Mcm proteins are engaged in processes related to regulation of transcription and/or chromatin organization. In oocytes preparing for meiotic maturation, aggregates of the insoluble form of Mcm2 fragmented, dispersed and ultimately disappeared from the nuclei. Numerous Mcm2-positive deposits were observed in the cytoplasm of maturing oocytes. In the one-cell embryo, insoluble Mcm2 appeared in the G1 nucleus, persisted in the S phase and was undetectable in the G2 nucleus. Such behavior of Mcm2 supports its involvement in chromatin licensing in the first embryonic cell cycle.
authors.affiliation: Department of Embryology, Institute of Zoology, Warsaw University, Warsaw, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Swiech
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kisiel
authors.forename: Renata
authors.initials: R
authors.lastname: Czolowska
authors.forename: Maciej
authors.initials: M
authors.lastname: Zientarski
authors.forename: Ewa
authors.initials: E
authors.lastname: Borsuk
mesh_terms: D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D003433:Crosses, Genetic; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D004622:Embryo, Mammalian; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D064111:Minichromosome Maintenance Complex Component 2; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; D009687:Nuclear Proteins / Q000096:biosynthesis*; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D009866:Oogenesis; D012995:Solubility; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000546:Amanitins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C491205:Mcm6 protein, mouse; C491086:Mcm7 protein, mouse; D064111:Minichromosome Maintenance Complex Component 2; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7