Long-Term Effects of In Vitro Growth of Mouse Oocytes on Their Maturation and Development

Obata, Yayoi; Maeda, Yuhei; Hatada, Izuho; Kono, Toru

doi:10.1262/jrd.19079

Cited by 15 publications

(15 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Breaks in the developmental "chain" have been bypassed previously through in vivo conditions by grafting PGCs beneath the renal capsules (7,8) or the ovarian bursa (9). We used a different kind of bypass, involving whole cytoplasm prepared from in vivo-grown oocytes, which was combined with genomic materials from in vitro-grown oocytes cultured from PGCs, using the nuclear transfer technique (11,26). All such bypasses demand additional animals and complex procedures.…”

Section: Discussionmentioning

confidence: 99%

Complete in vitro generation of fertile oocytes from mouse primordial germ cells

Morohaku

Tanimoto

Sasaki

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

168

145

View full text Add to dashboard Cite

Reconstituting gametogenesis in vitro is a key goal for reproductive biology and regenerative medicine. Successful in vitro reconstitution of primordial germ cells and spermatogenesis has recently had a significant effect in the field. However, recapitulation of oogenesis in vitro remains unachieved. Here we demonstrate the first reconstitution, to our knowledge, of the entire process of mammalian oogenesis in vitro from primordial germ cells, using an estrogenreceptor antagonist that promotes normal follicle formation, which in turn is crucial for supporting oocyte growth. The fundamental events in oogenesis (i.e., meiosis, oocyte growth, and genomic imprinting) were reproduced in the culture system. The most rigorous evidence of the recapitulation of oogenesis was the birth of fertile offspring, with a maximum of seven pups obtained from a cultured gonad. Moreover, cryopreserved gonads yielded functional oocytes and offspring in this culture system. Thus, our in vitro system will enable both innovative approaches for a deeper understanding of oogenesis and a new avenue to create and preserve female germ cells.oogenesis | primordial germ cells | follicle formation | oocytes | in vitro

show abstract

Section: Discussionmentioning

confidence: 99%

Complete in vitro generation of fertile oocytes from mouse primordial germ cells

Morohaku

Tanimoto

Sasaki

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

168

145

View full text Add to dashboard Cite

show abstract

“…Growing oocytes were isolated from the ovaries of 10-day-old mice or ovaries of newborn mice after 10 days of organ culture as previously reported [8,14]. Before every experiment, the diameter of the oocytes was measured using an interference microscope (200× magnification; Nikon, Tokyo, Japan) and an eyepiece micrometer (10×A; Nikon).…”

Section: Growing Oocytesmentioning

confidence: 99%

“…Serial nuclear transfers were performed as previously described [14]. Karyoplasts obtained from the growing oocytes were fused with fully grown enucleated GV stage oocytes using inactivated Sendai virus (2700 hemagglutinating activity units/ml).…”

Section: Nuclear Transfer and In Vitro Maturationmentioning

confidence: 99%

Epigenetically Immature Oocytes Lead to Loss of Imprinting During Embryogenesis

Obata

Hiura

Fukuda

et al. 2011

Journal of Reproduction and Development

Self Cite

View full text Add to dashboard Cite

Abstract. Loss of imprinting (LOI) is occasionally observed in human imprinting disorders. However, the process behind the LOI is not fully understood. To gain a better understanding, we produced embryos and pups from mouse oocytes that lacked a complete methylation imprint using a method that involved transferring the nuclei of growing oocytes into the cytoplasm of enucleated fully grown oocytes following in vitro fertilization (IVF). We then analyzed the imprinting statuses. Our findings show that the incomplete methylation imprint derived from growing oocytes results in epigenetic mosaicism or a loss of methylation imprint (LOM) at maternal alleles in embryos. In some embryos, both hypo-and hypermethylated maternal Kcnq1ot1 alleles were detected, whereas either hypo-or hypermethylated maternal Kcnq1ot1 alleles were detected in others. Such tendencies were also observed at the Igf2r and Mest loci. Gene expression levels of imprinted genes were linked with their methylation statuses in some but not all embryos. Possible explanations of the inconsistency between the data from DNA methylation and gene expression include epigenetic mosaicism in embryos. Pups were successfully produced from growing oocytes at a quite low frequency. They exhibited an obese phenotype and LOI with respect to Igf2r, Snrpn and Mest. Our finding suggests the possibility that LOI/LOM at maternal alleles in human concepti could be derived from epigenetically immature/mutated oocytes. Key words: DNA methylation, Gene expression, Genomic imprinting, Growing oocyte, Loss of imprinting (LOI) (J. Reprod. Dev. 57: [327][328][329][330][331][332][333][334] 2011) enomic imprinting is an epigenetic modification specifically imposed on male and female gametes that leads to the parental origin-specific gene expression in embryos. DNA methylation is the primary mechanism behind genomic imprinting [1,2]. Gamete-specific DNA methylation is established by DNA methyltransferase (DNMT) 3A and DNMT3L and is maintained after fertilization by DNMT1. Embryos derived from oocytes with defective Dnmt3a, Dnmt3L or Dnmt1 genes exhibit a LOM and the aberrant expression of imprinted genes (referred to LOI). In turn, this causes embryonic death [3][4][5]. Therefore, the regulatory expression of imprinted genes via DNA methylation is essential for normal ontogeny and biological phenomena in mammals.So far, we and other researchers have reported on the stage of the establishment of methylation imprints during mouse oocyte growth [6,7]. The results show that the Impact, Snrpn, Mest and Grb10 genes are hypermethylated in growing oocytes with diameters of 60-65 μm; the Igf2r, Kcnq1ot1 and Plagl1 genes are hypermethylated in growing oocytes with diameters of 55-60 μm. The first appearance of oocytes with complete methylation imprints at all of the examined loci is at an age of approximately 15 days in mice. Because fertilized eggs containing genomes from growing oocytes of mice 15 days old or younger do not develop into offspring, establishment of genomic imprinting is r...

show abstract

“…Embryos were reconstructed by serial NT. 35 Briefly, karyoplasts obtained from the growing oocytes were fused with fully grown enucleated germinal vesicle (GV)-stage oocytes using HVJ-E (GenomeONE-CF). The reconstructed oocytes were matured in TaM (1:1 mixture of α-MEM and TYH) as described previously.…”

Section: Animalsmentioning

confidence: 99%