Analysis of gene transcription in bovine nuclear transfer embryos reconstructed with granulosa cell nuclei

The low efficiency of animal production using somatic cell nuclear transfer procedures is considered to be the result of an incomplete reprogramming o f the donor somatic cell nucleus, which leads to a lack of, or abnormal exp ression of developmentally important genes. However, our current understand ing of the process of somatic cell nuclear reprogramming and its effect on gene expression is limited. In this study, we compare the transcription pat terns of six developmentally important genes, Oct4, IL6, FGF2, FGF4, FGFr2, and gp130 in single in vitro fertilized (IVF) and nuclear transfer embryos reconstructed using granulosa cells for the donor nuclei. Similar patterns of transcription were detected for Oct4, FGF2, and gp130 in IVF and nuclea r transfer embryos during the preimplantation stages of development. Howeve r, a number of morula- and blastocyst-stage embryos derived from nuclear tr ansfer procedures showed abnormal transcription of IL6, FGF4, and FGFr2. Pr evious studies have demonstrated that these three genes play an important r ole in implantation, early postimplantation development, or both in the mou se. Therefore, the aberrant transcription patterns detected in nuclear tran sfer embryos may lead to a reduction in embryo viability.