In mammals, unfertilized oocytes are one of the most available stages for cryopreservation because the cryopreserved oocytes can be used for assisted reproductive technologies, including in vitro fertilization (IVF) and intracytoplasmic sperm injection. However, it has generally been reported that the fertility and developmental ability of the oocytes are reduced by cryopreservation. C57BL/6J m...

We report an ion channel in the plasma membrane of unfertilized oocytes of the ascidian Ciona intestinalis that is directly gated by the second messenger ADP-ribose. The ion channel is permeable to Ca2+ and Na+ and is characterized by a reversal potential between 0 and +20 mV and a unitary conductance of 140 pS. Preinjection of the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane- N, N, N', N'-tetra...

Gene downregulation by antisense morpholino oligonucleotides (MOs) is achieved by either hybridization around the translation initiation codon or by targeting the splice donor site. In the present study, an antisense MO method is introduced that uses a 25-mer MO against a region at least 40-nt upstream from a poly(A) tail junction in the 3'-untranslated region (UTR) of maternal mRNA. The MO rem...

The immature oocyte and unfertilized eggs of Urechis caupo, a marine echiuroid worm, contain many nuclear bodies and a main nucleolus. These bodies are similar to prenucleolar bodies of other materials with respect to their origin, structure, cytochemical and biochemical characteristics. They are formed in large numbers during the diffuse diplotene stage, perhaps by an aggregation of nucleolar ...

Mammalian genomes can be edited by injecting pronuclear embryos with Cas9 cRNA and guide RNA (gRNA) but it is unknown whether editing can also occur during the onset of embryonic development, prior to pronuclear embryogenesis. We here report Cas9-mediated editing during sperm-induced meiotic exit and the initiation of development. Injection of unfertilized, mouse metaphase II (mII) oocytes with...

Partial or complete fertilization failure after IVF was reported in 5-10% of cycles. Total fertilization failure in patients with normal sperm parameters is rare but very stressful incident after IVF. To rescue the IVF cycles after total fertilization failure, ICSI of unfertilized oocytes after initial insemination has been reported.We reviewed a 2 years experience of rescue ICSI and analyzed t...

Meiotic maturation in mammalian oocytes is a complex process which involves extensive rearrangement of microtubules, actin filaments and chromosomes. Since cytoskeletal elements are sensitive to disruption by heat shock, a series of experiments were performed to determine whether physiologically relevant heat shock disrupts the progression of the oocyte through meiosis, fertilization and zygote...

BACKGROUND Cryopreservation is now considered as an efficient way to store human oocytes to preserve fertility. However, little is known about the effects of this technology on oocyte gene expression. The aim of this study was to examine the effect of the two cryopreservation procedures, slow freezing and vitrification, on the gene expression profile of human metaphase II (MII) oocytes. METHO...

Chromosomal aberrations are the major cause of pre- and post-implantation embryo wastage and some studies suggest that half of all human conception have a chromosomal abnormality. Analysis of gametes provides information on the origin of these chromosomal aberrations. The purpose of this study was to develop a reliable multi-probe fluorescence in-situ hybridization (FISH) procedure that would e...

Melatonin actions are mediated through G protein-coupled transmembrane receptors. Recently, mt1, mt2, and mel1c melatonin receptors were cloned in the Senegalese sole. Here, their day-night and developmental expressions were analyzed by quantitative PCR. These results revealed distinct expression patterns of each receptor through development. mel1c transcripts were more abundant in unfertilized...