STUDY QUESTION What is the subcellular localization in human oocytes and preimplantation embryos, of the two maternal-effect proteins, NLRP7 and KHDC3L, responsible for recurrent hydatidiform moles (RHMs)? SUMMARY ANSWER NLRP7 and KHDC3L localize to the oocyte cytoskeleton and are polar and absent from the cell-to-cell contact region in early preimplantation embryos. WHAT IS KNOWN ALREADY N...

The utilization of energy substrates by preimplantation mouse embryos undergoes several changes during development in vitro (Brinster, 1965a, b) but very little is known about the level of high-energy containing compounds, such as ATP at these stages. In the present study, the content ofATP in freshly collected preimplantation mouse embryos has been measured. For each estimation, fifty to 150 e...

BACKGROUND Fluorescence in situ hybridization (FISH) is the most widely used method for detecting unbalanced chromosome rearrangements in preimplantation embryos but it is known to have several technical limitations. We describe the clinical application of a molecular-based assay, array comparative genomic hybridization (array-CGH), to simultaneously screen for unbalanced translocation derivati...

Normally fertilized human embryos biopsied 3 days after in-vitro fertilization (IVF) have been examined for effects on viability and development in vitro after removal of one or two cells at the 8-cell stage (1/8 and 2/8) from each embryo. A high proportion of 7/8 and 6/8 biopsied and unmanipulated embryos developed to the blastocyst stage between days 5 and 6 (79, 71 and 59%, respectively), an...

BACKGROUND The majority of human embryos created using in vitro fertilisation (IVF) techniques are aneuploid. Comprehensive chromosome screening methods, applicable to single cells biopsied from preimplantation embryos, allow reliable identification and transfer of euploid embryos. Recently, randomised trials using such methods have indicated that aneuploidy screening improves IVF success rates...

Female mice generating oocytes lacking complex N- and O-glycans (double mutants (DM)) produce only one small litter before undergoing premature ovarian failure (POF) by 3 months. Here we investigate the basis of the small litter by evaluating ovulation rate and embryo development in DM (Mgat1(F/F)C1galt1(F/F):ZP3Cre) and Control (Mgat1(F/F)C1galt1(F/F)) females. Surprisingly, DM ovulation rate ...

Mitochondria, cellular organelles playing essential roles in eukaryotic cell metabolism, are thought to have evolved from bacteria. The organization of mtDNA is remarkably uniform across species, reflecting its vital and conserved role in oxidative phosphorylation (OXPHOS). Our objectives were to evaluate the compatibility of xenogeneic mitochondria in the development of preimplantation embryos...

Mitochondrial DNA (mtDNA) is normally only inherited through the oocyte. However, nuclear transfer (NT), the fusion of a donor cell with an enucleated oocyte, can transmit both donor cell and recipient oocyte mtDNA. mtDNA replication is under the control of nuclear-encoded replication factors, such as polymerase gamma (POLG) and mitochondrial transcription factor A (TFAM). These are first expre...

Alkaline phosphatase (AP) activity has been assayed in frozen sections of preimplantation mouse embryos by an azo-dye cytochemical method. The results indicate that during preimplantation mouse development AP activity is first expressed between the 8- and 16-cell stages and develops in all cells by the late morula stage. During blastocyst formation AP activity is lost or greatly reduced in trop...

DNA methylation patterns are dynamic in cleavage-stage embryos of a number of mammalian species. A failure to properly recapitulate preimplantation DNA methylation patterns in embryos derived by nuclear transfer may contribute to the low efficiency of nuclear transfer in producing live offspring.