Combined positive effect of oocyte extracts and brilliant cresyl blue stained recipient cytoplasts on epigenetic reprogramming and gene expression in buffalo nuclear transfer embryos.

Abstract

This study examined the effects of buffalo oocyte extracts (BOE) on donor cells reprogramming and molecular characterisation of oocytes screened via brilliant cresyl blue (BCB) staining and comparison of gene expression profiles of developmentally important genes in blastocysts from IVF and cloned derived from BOE treated donor cells with BCB selected recipient cytoplasts. Relative abundance (RA) of OCT4 and NANOG was increased (P<0.05) and HDAC-1, DNMT-1, and DNMT-3A decreased (P<0.05) in extract treated cells (ETCs). This ETCs dedifferentiated into neuron-like lineage under appropriate induction condition. The RA of NASP, EEF1A1, DNMT1, ODC1 and RPS27A was increased (P<0.05) in BCB+ oocytes, whereas ATP5A1 and S100A10 increased (P<0.05) in BCB- oocytes. Total cell number and RA of OCT4, NANOG, SOX2, DNMT1, IGF2, IGF2R, MNSOD, GLUT1, BAX and BCL2 in cloned blastocysts derived from BCB+ oocytes with ETC more closely followed that of IVF counterparts compared to BCB+ oocytes with extract untreated cell and BCB- oocytes with ETC derived blastocysts. In conclusion, BOE influenced epigenetic reprogramming of buffalo fibroblasts making them suitable donors for nuclear transfer (NT). BCB staining can be effectively used for selection of developmentally competent oocytes for NT. The combined effects of epigenetic reprogramming of donor nuclei by BOE and higher nuclear reprogramming capacity of BCB+ oocytes improve developmentally important gene expression in cloned blastocysts. Whether these improvements have long-term effects on buffalo calves born following embryo transfer remains unknown.