Methylation analysis of KvDMR1 in human oocytes

Geuns, Elke; Hilven, Pierre; Steirteghem, André Van; Liebaers, Ingeborg; Rycke, Martine De

doi:10.1136/jmg.2006.044149

Cited by 59 publications

(42 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…KCNQ1OT1 LOM was also observed in 5/23 and 2/37 DNA strands from IVM MII oocyte pools (Khoueiry et al 2008. This contrasts with short-term IVM MII oocytes that had normal SNRPN (three single oocytes), KCNQ1OT1 (four single oocytes), and MEG3 (GTL2) (three pools of two oocytes) methylation (Geuns et al 2003(Geuns et al , 2007a(Geuns et al , 2007b. In the above studies, where zona pellucidae were not removed, there is the possibility of cumulus cell contamination.…”

Section: In Vitro Oocyte Maturationmentioning

confidence: 42%

Genomic imprints as a model for the analysis of epigenetic stability during assisted reproductive technologies

Denomme¹,

Mann²

2012

Reproduction

112

118

View full text Add to dashboard Cite

Gamete and early embryo development are important stages when genome-scale epigenetic transitions are orchestrated. The apparent lack of remodeling of differential imprinted DNA methylation during preimplantation development has lead to the argument that epigenetic disruption by assisted reproductive technologies (ARTs) is restricted to imprinted genes. We contend that aberrant imprinted methylation arising from assisted reproduction or infertility may be an indicator of more global epigenetic instability. Here, we review the current literature on the effects of ARTs, including ovarian stimulation, in vitro oocyte maturation, oocyte cryopreservation, IVF, ICSI, embryo culture, and infertility on genomic imprinting as a model for evaluating epigenetic stability. Undoubtedly, the relationship between impaired fertility, ARTs, and epigenetic stability is unquestionably complex. What is clear is that future studies need to be directed at determining the molecular and cellular mechanisms giving rise to epigenetic errors.

show abstract

Section: In Vitro Oocyte Maturationmentioning

confidence: 42%

Genomic imprints as a model for the analysis of epigenetic stability during assisted reproductive technologies

Denomme¹,

Mann²

2012

Reproduction

112

118

View full text Add to dashboard Cite

show abstract

“…The development of the single-cell PCR for the IG-DMR was complex, and a rather low amplification efficiency (17.6%) was obtained, compared to similar protocols developed for the SNRPN-gene (28.7%) and the LIT1-gene (25.0%). 18,24 This was most probably due to the numerous tandem repeats present in the sequence of the IG-DMR.…”

Section: Discussionmentioning

confidence: 99%

Methylation analysis of the intergenic differentially methylated region of DLK1-GTL2 in human

et al. 2007

View full text Add to dashboard Cite

Imprinting is a non-Mendelian form of inheritance where epigenetic modifications control mono-allelic expression depending on the parental origin. Methylation of CpG-dinucleotides at differentially methylated regions (DMRs) is one of the best-studied mechanisms directing expression to one specific parental allele. We studied the methylation patterns of the intergenic (IG)-DMR of DLK1 and GTL2. The methylation marks of the IG-DMR were analysed in human gametes, preimplantation embryos, amniocytes and blood of babies born after intracytoplasmic sperm injection (ICSI) and blood from adults using a bisulphite sequencing technique. In oocytes, the IG-DMR was mainly unmethylated while in sperm cells a generally methylated pattern was detected. This germ-line specific methylation mark was maintained in the preimplantation embryos until the second cleavage stage. Afterwards in the preimplantation embryos, intermediate methylation patterns (26 -74% methylation) occurred, which may point to relaxation of the imprints. Intermediate patterns were also present in amniocytes, blood from ICSI babies and adults. We hypothesise that in the early cleavage stage embryo a strict differential methylation pattern is needed for the correct imprint establishment of surrounding imprinted genes. Once correct imprinting of the involved gene(s) is acquired, a more relaxed state of the IG-region is allowed.

show abstract

“…It is assu med that maternal hypomethylation syndrome, in which LOM occurs at multiple maternal loci, may be due to a lack of maternal DNMT3L or DNMT1, although mutation of theses genes is not detected in all patients [17]. In various cases, it is proposed that fertilized eggs derived from epigenetically mutated gametes could contribute to LOI/LOM regardless of whether conception occurs naturally or by ART [13,18,19].…”

Section: Discussionmentioning

confidence: 99%

“…Some investigators suggest that LOI/LOM could be attributed to assisted reproductive technology (ART) [10][11][12]. On the other hand, Geuns et al showed that 1 out of 16 human oocytes does not possess a KCNQ1OT1 methylation imprint [13]. We also report that the size-dependent acquisition of maternal methylation imprints is recognized in growing oocytes collected from adult mice as in juveniles; however, the hypomethylated alleles in the growing oocytes derived from adults are detected more remarkably than those of juveniles [7].…”

mentioning

confidence: 99%

Epigenetically Immature Oocytes Lead to Loss of Imprinting During Embryogenesis

Obata

Hiura

Fukuda

et al. 2011

Journal of Reproduction and Development

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

Methylation analysis of KvDMR1 in human oocytes

Cited by 59 publications

References 23 publications

Genomic imprints as a model for the analysis of epigenetic stability during assisted reproductive technologies

Genomic imprints as a model for the analysis of epigenetic stability during assisted reproductive technologies

Methylation analysis of the intergenic differentially methylated region of DLK1-GTL2 in human

Epigenetically Immature Oocytes Lead to Loss of Imprinting During Embryogenesis

Contact Info

Product

Resources

About