Reproduction Abstracts

Before fertilization, oocyte genome is not transcribed and this transcriptionally silent state continues after fertilization. It is known that in mice, the first gene expression in the life occurs at mid-1-cell stage and the expression pattern dramatically alters during development following the program of gene expression. However, the profile of transcribed genes and the mechanism regulating their expression at the 1-cell stage has not been clarified, since the amount of zygo...

After fertilization, differentiated oocytes become totipotent embryos. In this transition, a drastic change in chromatin structure is known to occur, although the mechanism underlying this change remains to be elucidated. Recent studies have revealed that one of the major factors that contribute to the change in the chromatin structure is the exchange of histones with their variants. In mammals, there are three main non-centromeric histone H3 variants: H3.1, H3.2, and H3.3. Us...

After the resumption of meiosis and fertilization, differentiated oocytes dramatically change their nature to generate totipotent zygotes. However, since transcription does not occur in oocytes and early 1-cell stage embryos, gene expression is controlled only by post-transcriptional regulation. There are huge mRNAs stored in full-grown oocytes (FGO). A part of them is not translated in FGO and MII stage oocytes, and become translated after the resumption of meiosis and fertil...