BACKGROUND Although chromosomal mosaicism in human preimplantation embryos has been described for almost two decades, its exact prevalence is still unknown. The prevalence of mosaicism is important in the context of preimplantation genetic screening in which the chromosomal status of an embryo is determined by the analysis of a single cell from that embryo. METHODS Here we report a systematic...

BACKGROUND Preimplantation development is a crucial step in early human development. However, the molecular basis of human preimplantation development is not well known. METHODOLOGY By applying microarray on 397 human oocytes and embryos at six developmental stages, we studied the transcription dynamics during human preimplantation development. PRINCIPAL FINDINGS We found that the preimplan...

Preimplantation embryo development follows a series of critical events. Remarkable epigenetic modifications and reprogramming of gene expression occur to activate the embryonic genome. In the early stages of preimplantation embryo development, maternal mRNAs direct embryonic development. Throughout early embryonic development, a differential methylation pattern is maintained although some show ...

Background: A prerequisite for successful embryo implantation is adequate preparation of receptive endometrium and the establishment and maintenance of a viable embryo. The success of implantation further relies upon a two-way dialogue between the embryo and uterus. However, molecular bases of these preimplantation and implantation processes in humans are not well known. Materials and Methods: ...

Indomethacin, an inhibitor of prostaglandin synthesis, depressed the incorporation of [3H]uridine into RNA of mouse preimplantation embryo, when it was injected in vivo or added in vitro. In contrast, prostaglandin F2 alpha decreased the inhibitory effect of indomethacin, when it was added in vitro with indomethacin. The results of these experiments suggest that prostaglandin F2 alpha plays a r...

Embryo biopsy for preimplantation genetic diagnosis can be performed on the oocyte/zygote, cleavage stage embryo, or blastocyst, but the majority of centres perform cleavage stage biopsy. Single-cell diagnosis is undertaken by the polymerase chain reaction or fluorescent in-situ hybridization. Technical difficulties have arisen with preimplantation genetic diagnosis, such as allele dropout and ...

This study investigates the suitability of surface-enhanced laser desorption and ionization time-of-flight (SELDI-TOF) and electrospray ionization (ESI) mass spectrometry for analysis of the proteins released by the mouse preimplantation embryo in vitro. SELDI-TOF analysis with CM10 or IMAC30 (but not Q10) protein chips detected a protein peak at m/z approximately 8570 released by both C57BL6 a...

GenBank contains 57,151 Expressed Sequence Tags (EST) derived from 11 preimplantation embryo mouse cDNA libraries ranging from the 2-cell embryo to the blastocyst. EST were matched to UniGene clusters to identify a composite set of 11,291 UniGenes. These 11,291 UniGenes were screened using HomoloGene to identify a subset of 3467 mouse UniGenes with matches in at least two other species, one of ...

The early preimplantation mouse embryo is a unique system where it is possible to explore the foundations of totipotency and differentiation. Following fertilization, a single cell, the zygote, will give rise to all tissues of the organism. The first signs of differentiation in the embryo are evident at the blastocyst stage with the formation of the trophectoderm, a differentiated tissue that e...

Imprinted genes are characterized by expression of only one of the two alleles according to its inheritance from the mother or the father. This mono-allelic expression must arise from primary differential epigenetic modification of the parental alleles of the imprinted gene in the spermatozoon and the oocyte. Most of the information on the onset of imprinted gene expression, and on the molecula...