Background: The oocyte is a unique cell committed to reprogram fertilizing sperm and to support early stages of embryonic development until the species-specific stage of zygote genome activation that occurs around the second to third cell cycle in sheep embryos. In this sense, considering the huge list of oocyte transcripts, we selected some candidates genes based on their roles of regulating di...

The mixing of mitochondrial DNA (mtDNA) from the donor cell and the recipient oocyte in embryos and offspring derived from somatic cell nuclear transfer (SCNT) compromises genetic integrity and affects embryo development. We set out to generate SCNT embryos that inherited their mtDNA from the recipient oocyte only, as is the case following natural conception. While SCNT blastocysts produced fro...

Nucleate and anucleate fragments of mouse oocytes have been isolated following treatment of fully grown oocytes with cytochalasin B. The nucleate oocyte fragments resume meiosis in vitro, progressing from dictyate of the first meiotic prophase to metaphase II ('meiotic maturation'), and exhibit all of the changes in protein synthesis normally associated with meiotic maturation of mouse oocytes....

In mouse somatic cell nuclear transfer (SCNT), polyvinylpyrrolidone (PVP) is typically included in the nuclear donor injection medium. However, the cytotoxicity of PVP, which is injected into the cytoplasm of oocytes, has recently become a cause of concern. In the present study, we determined whether bovine serum albumin deionized with an ion-exchange resin treatment (d-BSA) was applicable to t...

Most current studies of nuclear transfer in mammalian oocytes have used electrofusion to incorporate donor cell nuclei into enucleated oocyte cytoplasts. However, the application of electrofusion to human oocytes is hampered by the relative ease with which this procedure induces oocyte activation. Here we tested a previously described chemical fusion technique and an original mechanical fusion ...

The nucleus of eukaryotic cells is organized into functionally specialized compartments that are essential for the control of gene expression, chromosome architecture and cellular differentiation. The mouse oocyte nucleus or germinal vesicle (GV) exhibits a unique chromatin configuration that is subject to dynamic modifications during oogenesis. This process of 'epigenetic maturation' is critic...

Cloning by somatic cell nuclear transfer is an important technology, but remains limited due to poor rates of success. Identifying genes supporting clone development would enhance our understanding of basic embryology, improve applications of the technology, support greater understanding of establishing pluripotent stem cells, and provide new insight into clinically important determinants of oo...

Folliculogenesis is a progressive and highly regulated process, which is essential to provide ova for later reproductive life, requires the bidirectional communication between the oocyte and granulosa cells. This physical connection-mediated communication conveys not only the signals from the oocyte to granulosa cells that regulate their proliferation but also metabolites from the granulosa cel...

Input from various signaling pathways in conjunction with specific transcription factors (TFs), noncoding RNAs, and epigenetic modifiers governs the maintenance of cellular identity. Endogenous or exogenous TFs operate within certain boundaries, which are set, in part, by the cell type-specific epigenetic landscape. Ectopic expression of selected TFs can override the cellular identity and induc...