Thierry Blachère

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Imprinting is an epigenetic modification that is reprogrammed in the germ line and leads to the monoallelic expression of some genes. Imprinting involves DNA methylation. Maternal imprint is reset during oocyte growth and maturation. In vitro maturation (IVM) of oocytes may, therefore, interfere with imprint acquisition and/or maintenance. To evaluate if(More)
ART is suspected to generate increased imprinting errors in the lineage. Following an intra cytoplasmic sperm injection (ICSI) procedure, a certain number of embryos fail to develop normally and imprinting disorders may be associated to the developmental failure. To evaluate this hypothesis, we analysed the methylation profile of H19DMR, a paternally(More)
BACKGROUND Imprinted genes, many of which are involved in development, are marked during gametogenesis to allow their parent-of-origin specific expression, and DNA methylation at CpG islands is part of this epigenetic mark. Maternal imprint is apposed on oocyte during growth and maturation. Factors interfering with normal oocyte differentiation such as(More)
OBJECTIVE To evaluate the integrity of genomic imprinting in oocytes vitrified at the germinal vesicle (GV) stage and in vitro matured (IVM) after thawing. DESIGN Clinical research and application. SETTING University-based fertility center. PATIENT(S) Immature oocytes were donated for research by patients who were included in an intracytoplasmic sperm(More)
Summary To evaluate the integrity of genomic imprinting in embryos that failed to develop normally following intracytoplasmic sperm injection (ICSI), we analysed the methylation profile of H19 and KCNQ1OT1 imprinting control regions, H19DMR and KvDMR1 respectively, in high-grade blastocysts and in embryos that exhibited developmental anomalies. Significant(More)
Purified human SHBG was photoaffinity labeled with 17alpha-aminomethyl (M), 17alpha-aminoethyl (E), and 17alpha-aminopropyl (P) derivatives of [3alpha-(3)H]-5alpha-androstane-3beta,17beta-diol coupled to 5-azido-2-nitrobenzoylamido (ANB), 4-azido-2-nitrophenylamino (ANP), and 5-azido-2-nitro-3,4,6-trifluorophenylamino (ANTFP) chromophores. Successful(More)
STUDY QUESTION What is the methylation status of the Nanog and Oct4 promoters in human gametes and ICSI embryos and is abnormal reprogramming of their methylation associated with developmental failure of ICSI embryos? SUMMARY ANSWER Developmental failure of human ICSI embryos is associated with high methylation of the Oct4 promoter. WHAT IS KNOWN(More)
The use of round spermatids that are fully active at the transcriptional level to create zygotes (i.e. round spermatid injection; ROSI) raises the question regarding the downregulation of all specific genes that are transcribed from the paternal genome at fertilization. In this study, we show that protamine 1 and 2 mRNAs, which are specific to the round(More)
Purified rabbit and sheep sex hormone-binding globulins (SHBGs) were photolabeled by Delta 6-testosterone. The maximal levels of specific incorporation were respectively 0.33 and 0.30 mol of label/mol of homodimer. Tryptic cleavage of photolabeled SHBGs gave a single radioactive peptide for rabbit SHBG and two major radioactive peptides S1 and S2 for sheep(More)
Immunopurified human sex hormone binding globulin (SHBG) was photoinactivated and photolabeled by radioinert and radioactive photoaffinity labeling steroids delta 6-testosterone (delta 6-T) and delta 6-estradiol (delta 6-E2). The maximal levels of specific incorporation of these two reagents were 0.50 and 0.33 mol of label/mol of SHBG, respectively.(More)