
%0 Journal Article
%A Martinez-Diaz, M. A. 
%A Ikeda, K. 
%A Takahashi, Y. 
%T Effects of cycloheximide treatment and interval between fusion and activation on <emph type="2">in vitro</emph> development of pig nuclear transfer embryos
%J Reproduction, Fertility and Development
%D 2002/07/24
%V 14
%N 4
%P 191-197
%K cytoplasmic factors, electrical stimulus, nuclear status.
%R https://doi.org/10.1071/RD01114
%U https://www.publish.csiro.au/paper/RD01114 
%X The effects of cycloheximide (CHX) treatment and the interval between fusion and activation on the development of pig nuclear transfer (NT) embryos constructed with enucleated oocytes and serum-starved granulosa/cumulus cells were examined. One group of couplets was fused and activated simultaneously (FAS) by a single electrical pulse (activation pulse). Another three groups of couplets were fused electricaly 1.5, 2.5 or 4.5 h before being subjected to the activation pulse (FBA). Each group was divided into two subgroups and incubated with or without CHX. The NT embryos treated with CHX showed a high and stable cleavage rate, regardless of the interval between fusion and activation; however, development to blastocysts was improved only when the NT embryos were subjected to FAS with CHX. These results indicate that CHX-sensitive events occurring shortly after FAS may be responsible for the development to blastocysts. Fusion pulse rarely activated M II oocytes, but rapidly dropped the p34cdc2 kinase activity in NT embryos. A pronucleus-like structure was observed 2-2.5 h after the activation pulse with CHX in NT embryos of both the FAS and FBA groups. Therefore, successive inactivation of M-phase promoting factor and cytostatic factor at a certain short interval may also play an important role in the development of NT embryos. 
