The RNA binding protein LIN28A mediates chromatin dynamics during neuronal differentiation

Abstract

The transition of embryonic stem cells (ESCs) from pluripotency to lineage commitment is regulated by multiple mechanisms, including chromatin dynamics and both transcriptional and post-transcriptional processes. Recent advances have highlighted that these mechanisms often interact, forming intricate multi-layered regulatory networks that require detailed characterization. In this study, we demonstrate that the RNA-binding protein LIN28A plays a pivotal role in neuronal differentiation by mediating RNA-dependent interactions with the Polycomb repressive complex 2 (PRC2). This interaction facilitates the eviction of PRC2 from chromatin, thereby activating a neuronal lineage-specific transcriptional program. Proteomic analyses revealed that the LIN28A interactome undergoes substantial remodeling during differentiation, corresponding to changes in LIN28A localization. In ESCs, LIN28A is predominantly nuclear and interacts with several components of the PRC2 complex in an RNA-dependent manner, assisting in chromatin dynamics. Our findings show that in the absence of LIN28A, PRC2 remains associated with chromatin, impairing the expression of genes critical for neuronal differentiation in ESCs. Chromatin immunoprecipitation sequencing (ChIP-seq) further confirmed that loss of LIN28A results in preferential PRC2 occupancy at the promoters of differentiation-associated genes. This study uncovers a novel role for LIN28A in epigenetic remodeling, which is essential for the proper differentiation of ESCs into the neuronal lineage.