In vitro production of zebra cloned embryos

Abstract

Several equids have gone extinct, and many extant equids are currently considered vulnerable to critically endangered. In vitro embryo production has been promoted for genetic rescue and preservation potential over the last few years. This work aimed to evaluate whether domestic horse oocytes support preimplantation development of SCNT reconstructed embryos using zebra fibroblast and compare blastocyst quality through the expression of SOX2 and YAP1. Oocyte collection, SCNT, culture, blastocyst fixation, IF, and statistical analysis were performed as described by Gambini et al. 2020, PLoSONE,15(9):e0238948. Interestingly, the blastocyst rate of zebra SCNT was higher than the control group (Table 1). No significant differences were found in total cell numbers (cell number ± SEM) between horse (386,4±70,89) and zebra (285,8±41,13) SCNT blastocyst. All blastocysts showed a similar expression pattern of SOX2 and nuclear YAP1. Most nuclei were positive for YAP1 (trophectoderm lineage), and most SOX2+ nuclei were clustered and negative for YAP1 (inner cell mass lineage). A few blastocysts of each group showed a scattered pattern expression of the SOX2 protein, probably due to alterations during cellreprogramming of SCNT embryos. We demonstrated that domestic horse oocytes support reprogramming zebra cells and the subsequent preimplantation development without compromising blastocyst cell number neither the differentiation of inner cell mass nor trophectoderm lineages. Our results encourage the use of domestic horse oocytes as a model to study in vitro zebra embryos to preserve valuable genetics in conservation programs for endangered or extinct equid species.