Dissection of uniparental reproduction barriers in mice using haploid embryonic stem cells [RNA-Seq]

Uniparental reproduction is widespread among lower vertebrates, but not in mammals. Researchers have produced bimaternal mice with a deletion of the H19 imprinted region. However, the mechanism of a single deletion in an immature oocyte sufficient to cross uniparental barriers is unknown. We found bimaternal-derived mice to be defective in multiple aspects. More importantly, bipaternal reproduction has not been achieved in mammals. Thus, the barrier of uniparental reproduction in mammals has not been elucidated. We identified a DNA hypomethylation status in haploid embryonic stem cells similar to that in primordial germ cells, with which bimaternal and bipaternal mice can be obtained by injection of haploid ES cells with genetic modifications. The phenotypic analyses of derived mice support the genetic conflict theory of genomic imprinting. Taken together, our results highlight the factors necessary for crossing uniparental reproduction barriers in mammals. mRNA profiles of different type mouse embryos, brains and ESCs were generated by RNA sequencing using Illumina HiSeq 2500. The differentially methylated regions (DMRs) modified haploid ESCs were used to produce the embryos, including KO2 (knocking out H19-DMR and IG-DMR), KO3 (knocking out H19-DMR, IG-DMR, and Rasgrf1-DMR) as well as KO7 (knocking out Nespas-DMR, Grb10-DMR, Igf2r-DMR, Snrpn-DMR, Kcnq1-DMR, Peg3-DMR and Gnas-DMR) samples.