Reprogramming donor cells with oocyte extracts improves in vitro development of nuclear transfer embryos

This study investigated the effects of donor cells pretreated with oocyte extracts on in vitro development of cloned embryos. Bovine fibroblasts were exposed to immature, mature and parthenogenetic oocyte extracts respectively before nuclear transfer. The detectable expression of Oct4 and global cleacetylation in the treated cells showed that extracts could reprogram fibroblasts. Although all three groups of extracts exhibited reprogramming capacity, embryo development was not compliant with reprogramming effect. Improved quality and development of blastocysts were observed only in the mature extract treated group. We demonstrated that pretreatment of donor cells with mature oocyte extract improved in vitro development of cloned embryos. Our results suggested that reprogramming donor nuclei to a state synchronized with recipient cytoplasm before nuclear transfer would be beneficial for the development of cloned embryos. (C) 2008 Elsevier B.V. All rights reserved.