Effect of taxonomical distance and scriptaid on iSCNT embryo development in suidae

Very low efficiency limits the application of interspecies somatic cell nuclear transfer (iSCNT) on preserving endangered species. Our study demonstrated when taxonomical distance increased from intra-species to inter-species to inter-subfamily, the blastocyst rates decreased gradually (27.8% to 12.4% to 0). Scriptaid treatment significantly improved blastocyst rate of Bearded pig iSCNT embryos, accelerated the division timing and enhanced the level of H3K9ac at earlier stages. Transcriptome analysis revealed that half of the comparison groups based on taxonomical relations or Scriptaid treatment, displayed high proportion of enriched GO terms related to mitochondrion structure and/or function. Inter-subfamily or inter-species comparison groups reflected in downregulated differentially expressed genes (DEGs) or upregulated DEGs, contrarily. Accordingly, all these comparison groups displayed KEGG pathway enrichment to oxidative phosphorylation under their top pathways. The key genes related to the GO terms were identified for taxonomical relations or Scriptaid treatment, which are mainly from the NADH-ubiquinone oxidoreductase (NDUF) or ND gene family, separately. These findings suggest that taxonomical distance or Scriptaid treatment is closely associated with development fate of iSCNT embryos in Suidae through regulating the expression of mitochondrion-related genes. Our distinct contribution is identifying specific dysregulation in the NDUF (nuclear-encoded) and ND (mitochondrially encoded) gene families as a potential molecular basis for the "taxonomic wall," specifically showing how Scriptaid partially rescues this uncoupling.