Maternal primary imprinting is established at a specific time for each gene throughout oocyte growth.
Primary imprinting during gametogenesis governs the monoallelic expression/repression of imprinted genes in embryogenesis. Previously, we showed that maternal primary imprinting is disrupted in neonate-derived non-growing oocytes. Here, to investigate precisely when and in what order maternal primary imprinting progresses, we produced parthenogenetic embryos containing one genome from a non-growing or growth-stage oocyte from 1- to 20-day-old mice and one from a fully grown oocyte of adult mice. We used these embryos to analyze the expression of eight imprinted genes: Peg1/Mest, Peg3, Snrpn, Znf127, Ndn, Impact, Igf2r, and p57(KIP2). The results showed that the imprinting signals for each gene were not all imposed together at a specific time during oocyte growth but rather occurred throughout the period from primary to antral follicle stage oocytes. The developmental ability of the constructed parthenogenetic embryos was gradually reduced as the nuclear donor oocytes grew. These studies provide the first insight into the process of primary imprinting during oocyte growth.
Obata
Yayoi
Y
Gene Research Center, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
Kono
Tomohiro
T
D000483:Alleles; D000818:Animals; D001324:Autoantigens / Q000096:biosynthesis; D050761:Cyclin-Dependent Kinase Inhibitor p57; D005260:Female; D018392:Genomic Imprinting; D047908:Intracellular Signaling Peptides and Proteins; D051741:Kruppel-Like Transcription Factors; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008954:Models, Biological; D009035:Mothers; D009687:Nuclear Proteins / Q000096:biosynthesis; D009865:Oocytes / Q000378:metabolism / Q000502:physiology*; D014176:Protein Biosynthesis; D011494:Protein Kinases; D011506:Proteins; D017527:Receptor, IGF Type 2 / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012261:Ribonucleoproteins / Q000096:biosynthesis; D017411:Ribonucleoproteins, Small Nuclear; D013997:Time Factors; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D055517:snRNP Core Proteins
D001324:Autoantigens; C493965:Cdkn1c protein, mouse; D050761:Cyclin-Dependent Kinase Inhibitor p57; C484600:IMPACT protein, human; C107747:Impact protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D051741:Kruppel-Like Transcription Factors; D009687:Nuclear Proteins; C490820:PEG3 protein, human; C097901:Peg3 protein, mouse; D011506:Proteins; D017527:Receptor, IGF Type 2; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D014157:Transcription Factors; C103637:mesoderm specific transcript protein; D055517:snRNP Core Proteins; C119425:MKRN3 protein, human; D044767:Ubiquitin-Protein Ligases; D011494:Protein Kinases