DIS3L, cytoplasmic exosome catalytic subunit, is essential for development but not cell viability in mice

Among numerous enzymes involved in RNA decay, processive exoribonucleases are the most prominent group responsible for the degradation of entire RNA molecules. The role of mammalian cytoplasmic 3'-5' exonuclease DIS3L at the organismal level remained unknown. Herein, we established knock-in and knockout (KO) mouse models to study DIS3L functions in mice. DIS3L in mice is indeed a subunit of the cytoplasmic exosome complex, the disruption of which leads to severe embryo degeneration and death in mice soon after implantation. These changes could not be prevented by supplementing extraembryonic tissue with functional DIS3L through the construction of chimeric embryos. Preimplantation Dis3l ^-/- embryos were unaffected in their morphology and ability to produce functional embryonic stem (ES) cells, showing that DIS3L is not essential for cell viability. There were also no major changes at the transcriptome level for both ES cells and blastocysts, as revealed by RNA-seq experiments. Notably, however, Dis3l KO led to inhibition of global protein synthesis. These results point to the essential role of DIS3L in mRNA metabolism, which is crucial for proper protein synthesis during embryo development.