ELL3 Marked LINE-1 Serve as Enhancers to Regulate NaïvePluripotency in Mouse ESC

Retrotransposons make up more than 40% of the mouse genome and have a significant impacton the evolution and structure of the host genome. LINE-1s are a major group of retrotransposons that have theability to autonomously transpose. Despite the potential for gene toxicity, LINE-1s are highly activated during the early stages of embryo development. In the study, LIN and colleagues have identified a subset of youngLINE-1s, called L1Md_Ts, that are marked by ELL3 and function as enhancers in naïve mouse ESCs (embryonicstem cells). Depletion of ELL3 results in a loss of 5hmC, an increase in H3K27ac, and an up-regulation of genesnear the L1Md_Ts. Specifically, ELL3 occupies and represses an enhancer within Akt3, which is a key regulatorof the AKT pathway. ELL3 is essential for proper ERK activation in both mouse ESC and pre-implantation embryos. This study reveals the significance of ELL3 in governing the enhancer function of L1Md_Ts in the regulation of pluripotency in ESC.

CSTR: 32200.14.cjcb.2023.11.0002