RNA exosome ribonuclease DIS3 degrades Pou6f1 to promote mouse pre-implantation cell differentiation

Abstract

Mammalian development is precisely controlled by cell differentiation. Discovery of new regulators and investigating their crosstalk provide insights into genetic networks defining pre-implantation development. To identify novel developmental repressors, we established a knockout mouse model of Dis3, an RNA exosome associated RNase. Homozygous Dis3 null embryos arrest at the morula-to-blastocyst transition. Using single embryo RNA-seq, we discovered persistence of Pou6f1 mRNA in homozygous null Dis3 embryos and determined that the cognate protein represses transcription of Nanog and Cdx2. The resultant defects in cell differentiation disrupted the morula-to-blastocyst transition and was embryonic lethal. To overcome the paucity of embryos, homozygous Dis3 null mouse embryonic stem cells were derived to identify additional gene targets of POU6F1. While microinjection of the Dis3 cRNA into zygotes rescued the morula-to-blastocyst block, point mutations of Dis3 in individual blastomeres transformed the cell and prevented incorporation into embryos. Our findings uncover a not heretofore reported regulatory pathway of DIS3-POU6F1 in pre-implantation mammalian embryogenesis. In BriefMammalian pre-implantation development is regulated by master transcription factors and their crosstalk. Wu and Dean report that an RNA exosome associated RNase, DIS3, degrades Pou6f1 mRNA to de-repress transcription of Nanog and Cdx2 genes. In the absence of DIS3, POU6F1 protein persists and embryos arrest as morulae unable to become blastocysts due to lack of cell differentiation. HighlightsO_LIDis3 knockout mice have morula arrest due to lack of cell differentiation. C_LIO_LIDIS3 binds and degrades Pou6f1 mRNA before the morula stage. C_LIO_LIPOU6F1 globally occupies promoters to regulate gene transcription. C_LIO_LIDIS3 mutation results in cell transformation in embryonic development. C_LI