Genome stabilization by RAD51 stimulatory compound-1 enhances efficiency of somatic cell nuclear transfer-mediated reprogramming and full-term development of cloned mouse embryos

Here, we observed that the activity of Rad 51, a key modulator of homologous recombination repair (HRR) is lower in somatic cell nuclear transfer (SCNT)-derived eggs than in conventional IVF, and found a significantly lower level of DNA double-strand breaks (DSBs) in SCNT eggs during reprogramming. To address this difference, supplementation with RS-1, an activator of Rad51, during the activation of SCNT eggs can increase RAD51 expression and DSB foci and thereby overcome the developmental block. This protocol finally increased the efficiency of SCNT reprogramming. Through subsequent single-cell RNA-seq analysis, we observed the reactivation of a large number of genes that were not expressed in SCNT-2-cell embryos by the upregulation of HRR, which may be related to overcoming the developmental block. Additionally, there may be an independent pathway involving histone demethylase that can reduce reprograming resistance regions. This technology can contribute to the production of comparable cell sources for regenerative medicine.