AUTHOR=Rhodes Christopher T. , Asokumar Dhanya , Sohn Mira , Naskar Shovan , Elisha Lielle , Stevenson Parker , Lee Dongjin R. , Zhang Yajun , Rocha Pedro P. , Dale Ryan K. , Lee Soohyun , Petros Timothy J. TITLE=Loss of Ezh2 in the medial ganglionic eminence alters interneuron fate, cell morphology and gene expression profiles JOURNAL=Frontiers in Cellular Neuroscience VOLUME=Volume 18 - 2024 YEAR=2024 URL=https://www.frontiersin.org/journals/cellular-neuroscience/articles/10.3389/fncel.2024.1334244 DOI=10.3389/fncel.2024.1334244 ISSN=1662-5102 ABSTRACT=Introduction

Enhancer of zeste homolog 2 (Ezh2) is responsible for trimethylation of histone 3 at lysine 27 (H3K27me3), resulting in repression of gene expression. Here, we explore the role of Ezh2 in forebrain GABAergic interneuron development.

Methods

We removed Ezh2 in the MGE by generating Nkx2-1Cre;Ezh2 conditional knockout mice. We then characterized changes in MGE-derived interneuron fate and electrophysiological properties in juvenile mice, as well as alterations in gene expression, chromatin accessibility and histone modifications in the MGE.

Results

Loss of Ezh2 increases somatostatin-expressing (SST+) and decreases parvalbumin-expressing (PV+) interneurons in the forebrain. We observe fewer MGE-derived interneurons in the first postnatal week, indicating reduced interneuron production. Intrinsic electrophysiological properties in SST+ and PV+ interneurons are normal, but PV+ interneurons display increased axonal complexity in Ezh2 mutant mice. Single nuclei multiome analysis revealed differential gene expression patterns in the embryonic MGE that are predictive of these cell fate changes. Lastly, CUT&Tag analysis revealed that some genomic loci are particularly resistant or susceptible to shifts in H3K27me3 levels in the absence of Ezh2, indicating differential selectivity to epigenetic perturbation.

Discussion

Thus, loss of Ezh2 in the MGE alters interneuron fate, morphology, and gene expression and regulation. These findings have important implications for both normal development and potentially in disease etiologies.