De novo assembly and delivery of synthetic megabase-scale human DNA into mouse early embryos
Yue Liu, Jianting Zhou, Duo Liu, Xiaoyu Hu, Lin Yang, Xueru Song, Xiaodong Jin, Wei Xie, Luhan Yang, Zichuan Liu, Ying‐Jin Yuan
Abstract
Epigenetic modifications on natural chromosomes are inherited and maintained in a default state, making it challenging to remove intrinsic marks to study the fundamental principles of their establishment and further influence on transcriptional regulation. In this study, we developed SynNICE, a method for assembling and delivering intact, naive, synthetic megabase (Mb)-scale human DNA into early mouse embryos, to study de novo epigenetic regulation. By assembling and delivering a 1.14-Mb human AZFa (hAZFa) locus, we observed the spontaneous incorporation of murine histones and the establishment of DNA methylation at the one-cell stage. Notably, DNA methylation from scratch strongly enriches at repeat sequences without H3K9me3 reinforcement. Furthermore, the transcription of hAZFa initiated at the four-cell stage is regulated by newly established DNA methylation. This method provides a unique platform for exploring de novo epigenomic regulation mechanisms in higher animals. This work presents a strategy for synthesizing and assembling megabase-scale DNA, along with a delivery method for introducing the synthetic DNA into mouse embryos, offering a valuable tool for investigating de novo epigenetic regulation.