The Dual Role of EPOP and Elongin BC in Controlling Transcriptional Activity

Polycomb repressive complex 2 accessory factors: rheostats for cell fate decision?

Epigenetic reprogramming during development is key to cell identity and the activities of the Polycomb repressive complexes are vital for this process. We focus on polycomb repressive complex 2 (PRC2), which catalyzes H3K27me1/2/3 and safeguards cellular integrity by ensuring proper gene repression. Notably, various accessory factors associate with PRC2, strongly influencing cell fate decisions, and their deregulation contributes to various illnesses. Yet, the exact role of these factors during development and carcinogenesis is not fully understood. Here, we present recent progress toward addressing these points and an analysis of the expression levels of PRC2 accessory factors in various tissues and developmental stages to highlight their abundance and roles. Last, we evaluate their contribution to cancer-specific phenotypes, providing insight into novel anticancer therapies.

Early-life exercise primes the murine neural epigenome to facilitate gene expression and hippocampal memory consolidation

Aerobic exercise is well known to promote neuroplasticity and hippocampal memory. In the developing brain, early-life exercise (ELE) can lead to persistent improvements in hippocampal function, yet molecular mechanisms underlying this phenomenon have not been fully explored. In this study, transgenic mice harboring the "NuTRAP" (Nuclear tagging and Translating Ribosome Affinity Purification) cassette in Emx1 expressing neurons ("Emx1-NuTRAP" mice) undergo ELE during adolescence. We then simultaneously isolate and sequence translating mRNA and nuclear chromatin from single hippocampal homogenates containing Emx1-expressing neurons. This approach allowed us to couple translatomic with epigenomic sequencing data to evaluate the influence of histone modifications H4K8ac and H3K27me3 on translating mRNA after ELE. A subset of ELE mice underwent a hippocampal learning task to determine the gene expression and epigenetic underpinnings of ELE's contribution to improved hippocampal memory performance. From this experiment, we discover gene expression - histone modification relationships that may play a critical role in facilitated memory after ELE. Our data reveal candidate gene-histone modification interactions and implicate gene regulatory pathways involved in ELE's impact on hippocampal memory.