| Popis: |
Retrotransposons mediate gene regulation in multiple developmental and pathological processes. Here, we characterized the transient retrotransposon induction in preimplantation development of eight mammalian species. While species-specific in sequences, induced retrotransposons exhibit a similar preimplantation profile, conferring gene regulatory activities particularly through LTR retrotransposon promoters. We investigated a mouse-specific MT2B2 retrotransposon promoter, which generates an N-terminally truncated, preimplantation-specific Cdk2ap1ΔN isoform to promote cell proliferation. Cdk2ap1ΔN functionally contrasts to the canonical Cdk2ap1, which represses cell proliferation and peaks in mid-gestation stage. The mouse-specific MT2B2 element is developmentally essential, as its deletion abolishes Cdk2ap1ΔN, reduces cell proliferation and impairs embryo implantation. Intriguingly, Cdk2ap1ΔN is evolutionarily conserved across mammals, driven by species-specific promoters. The distinct preimplantation Cdk2ap1ΔN expression across different mammalian species correlates with their different duration in preimplantation development. Hence, species-specific transposon promoters can yield evolutionarily conserved, alternative protein isoforms, bestowing them with new functions and species-specific expression to govern essential biological divergence.One Sentence SummaryIn mammalian preimplantation embryos, retrotransposon promoters generate conserved gene isoforms, confer species-specific expression, and perform essential developmental functions. |
