Mouse totipotent stem cells captured and maintained through spliceosomal repression

Since establishment of the first embryonic stem cells (ESCs), in vitro culture of totipotent cells functionally and molecularly comparable with in vivo blastomeres with embryonic and extraembryonic developmental potential has been a challenge. Here we report that spliceosomal repression in mouse ESCs drives a pluripotent-to-totipotent state transition. Using the splicing inhibitor pladienolide B, we achieve stable in vitro culture of totipotent ESCs comparable at molecular levels with 2- and 4-cell blastomeres, which we call totipotent blastomere-like cells (TBLCs). Mouse chimeric assays combined with single-cell RNA sequencing (scRNA-seq) demonstrate that TBLCs have a robust bidirectional developmental capability to generate multiple embryonic and extraembryonic cell lineages. Mechanically, spliceosomal repression causes widespread splicing inhibition of pluripotent genes, whereas totipotent genes, which contain few short introns, are efficiently spliced and transcriptionally activated. Our study provides a means for capturing and maintaining totipotent stem cells.

Automated summary

This study demonstrates that spliceosomal repression in mouse ESCs can drive a transition from pluripotent state to totipotent state, allowing for stable in vitro culture of totipotent ESCs comparable to 2- and 4-cell blastomeres at molecular levels. These cells, named totipotent blastomere-like cells (TBLCs), exhibit a robust bidirectional developmental capability to generate multiple embryonic and extraembryonic cell lineages.