The connexin multigene family (13 characterized members in rodents) encodes the subunits of gap junction channels. Gap junctional intercellular coupling, established during compaction of the preimplantation mouse embryo, is assumed to be necessary for development of the blastocyst. One member of the connexin family, connexin43, has been shown to contribute to the gap junctions that form during ...

Interspecies somatic cell nuclear transfer (iSCNT) involves the transfer of a nucleus or cell from one species into the cytoplasm of an enucleated oocyte from another. Once activated, reconstructed oocytes can be cultured in vitro to blastocyst, the final stage of preimplantation development. However, they often arrest during the early stages of preimplantation development; fail to reprogramme ...

Currently in vitro culture of mouse preimplantation embryos has become a very important technique to investigate different mechanisms of early embryogenesis. However, there is a big difference in the preimplantation development between mammalian species. Despite close relatedness to mice, in vitro cultivation of rat preimplantation embryos is still delicate and needs further investigation and o...

BACKGROUND During human preimplantation development, early blastomeres are believed to be totipotent. It is likely, however, that blastomeres are allocated to a specific lineage prior to any morphological differentiation. NANOG, SOX2 and SALL4 are transcription factors that play a key role in controlling stemness in embryonic stem cells (ESC) and are therefore candidate markers for developmenta...

The potential for implantation of human embryos obtained by in-vitro fertilization is presumably determined to a large extent by their chromosomal constitution but cytogenetic analysis of preimplantation embryos has been hampered by a number of practical and technical problems. With the advent of fluorescent in-situ hybridization (FISH) a practical method for numerical chromosomal analysis has ...

BACKGROUND While mammalian cortical granules are important in fertilization, their biochemical composition and functions are not fully understood. We previously showed that the ABL2 antibody, made against zona free mouse blastocysts, binds to a 75-kDa cortical granule protein (p75) present in a subpopulation of mouse cortical granules. The purpose of this study was to identify and characterize ...

ETEROSIS in characteristics which are part of the reproductive process is a commonly observed result of crossing unrelated stocks in many species (e.g., GOWEN 1952). In mammals, the observed heterosis in litter size could be due to superiority of the crossbred in ovulation rate, in embryo survival, or both. The second of these parameters can be further subdivided into preand postimplantation st...

Glycogen synthase kinase-3 (GSK-3) is a highly conserved serine/threonine protein kinase implicated in diverse cellular processes. Activity of GSK-3 is essential for meiotic chromatin segregation in oocytes, yet expression and/or function of GSK-3 have not been reported in mammalian preimplantation embryos. Objectives of this study were to characterize GSK-3 protein expression/phosphorylation i...

BACKGROUND In preimplantation mammalian development the transcription factor Sox2 (SRY-related HMG-box gene 2) forms a complex with Oct4 and functions in maintenance of self-renewal of the pluripotent inner cell mass (ICM). Previously it was shown that Sox2-/- embryos die soon after implantation. However, maternal Sox2 transcripts may mask an earlier phenotype. We investigated whether Sox2 is i...

BACKGROUND INFORMATION The MAPK (mitogen-activated protein kinase) superfamily of proteins consists of four separate signalling cascades: the c-Jun N-terminal kinase or stress-activated protein kinases (JNK/SAPK); the ERKs (extracellular-signal-regulated kinases); the ERK5 or big MAPK1; and the p38 MAPK group of protein kinases, all of which are highly conserved. To date, our studies have focus...