Reproduction Abstracts

Somatic cell nuclear transfer (SCNT) has a broad spectrum of many potential applications but the efficiency is still disappointingly low. It is known that major cause of it, is incorrect or incomplete reprogramming of the transferred donor nuclei.

Many report indicates that Wnt/β-catenin signaling pathway plays a pivotal role in the process of somatic cell reprogramming. As CHIR is known as one of the activators of Wnt pathway by inhibiting glycogen synthase kinase 3β (Gsk 3β), this helps to maintain the undifferentiated state of human and mouse embryonic stem cells, preserving the expression of main pluripotent genes.

Here we verify whether CHIR-treated donor cells are better reprogrammable upon nuclear transfer in sheep and mouse models.

CHIR-treated cells were used as donors for SCNT, and then the subsequent in vitro and in vivo quality and development of the reconstructed embryos were assessed.

Results showed significant differences in the cleavage rate (63% – CTRL to 72% CHIR – mouse; 60.3% CTRL to 79% CHIR – sheep) and blastocyst formation (18.8 vs 29.6% – sheep). Additionally, CHIR cloned blastocysts exhibited very robust, better-expanded morphologies than CTRL ones. Moreover, significant improvement of the total and inner cell mass (ICM) cells numbers in CHIR blastocysts have been observed. Those results can lead to better development of live offspring (experiments on going).

Donor cells, treated with Gsk 3β inhibitor, are easier reprogrammed upon nuclear transfer and help to improve quality of preimplantation cloned embryos. Future optimization of SCNT protocol may allow this approach to be effective on higher efficiency of live cloned offspring.