EED

EED
**Full Name**	Embryonic Ectoderm Development
**Gene Symbol**	EED
**Aliases**	WAIT1, HEED, ESC
**Chromosome**	11q14.2
**Gene Type**	Protein-coding
**OMIM**	[605984](https://omim.org/entry/605984)
**UniProt**	[O75530](https://www.uniprot.org/uniprot/O75530)
**HGNC**	[3188](https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:3188)
**Entrez Gene**	[8726](https://www.ncbi.nlm.nih.gov/gene/8726)
**Ensembl**	[ENSG00000074266](https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000074266)
Variant	Type
R236T	Missense
H258Y	Missense
EED promoter methylation	Epigenetic
Associated Diseases	Als, Cancer, Inflammation
KG Connections	71 edges

Overview

EED is a human gene. Variants in EED have been implicated in Alzheimer’s Disease, Huntington’s Disease, Parkinson’s Disease. This page covers the gene’s normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.

EED (Embryonic Ectoderm Development) encodes a core scaffolding subunit of Polycomb Repressive Complex 2 (PRC2), the multisubunit complex responsible for trimethylation of histone H3 at lysine 27 (H3K27me3).^[1] EED functions as the allosteric activator of PRC2 by binding existing H3K27me3 marks through its WD40 repeat domain, creating a positive feedback loop that enables spreading of this repressive histone modification across chromatin.^[2] In the nervous system, EED is essential for neural fate specification, maintenance of neuronal subtype identity, and repression of non-neuronal transcriptional programs. Disruption of EED-PRC2 function contributes to Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease.

Function and Mechanism

EED is a WD40 repeat protein that forms a seven-bladed beta-propeller structure. It associates with EZH2 (or EZH1) and SUZ12 to form the catalytically active PRC2 core complex. EED performs two critical functions: structural scaffolding of the PRC2 complex and allosteric activation of the methyltransferase.

Allosteric Activation of PRC2

EED’s aromatic cage (formed by residues F97, Y148, Y153, Y365 in its WD40 domain) recognizes and binds H3K27me3 on adjacent nucleosomes. This binding event induces a conformational change that is transmitted through the EED-EZH2 interface to the SET domain of EZH2, stimulating methyltransferase activity approximately 7-fold.^[2] This read-write mechanism enables PRC2 to propagate H3K27me3 along chromatin fibers, spreading repressive domains from nucleation sites.

PRC2 Complex Assembly

EED interacts with EZH2 through its WD40 domain (binding the EZH2 EED-binding domain, EBD) and with SUZ12 through additional contacts. Without EED, EZH2 cannot fold properly and is rapidly degraded, making EED essential for PRC2 stability and catalytic function.^[3]

Neural Fate Determination

During neural development, EED-PRC2 silences mesodermal and endodermal lineage genes, restricting progenitor cells to neural fates. EED also controls the temporal switch from neurogenesis to gliogenesis by progressively silencing proneural transcription factors. Conditional Eed deletion in neural progenitors leads to premature neurogenesis, ectopic gene expression, and postnatal lethality.^[4]

Neuronal Subtype Maintenance

In postmitotic neurons, EED-PRC2 maintains cell-type-specific transcriptional programs by silencing alternative neuronal subtype genes. Loss of EED in mature neurons leads to gradual derepression of inappropriate gene programs and progressive neurodegeneration.^[5]

Disease Associations

Alzheimer’s Disease

H3K27me3 levels are globally altered in Alzheimer’s disease brains, with both gains and losses at specific loci. EED expression declines in AD hippocampal neurons, reducing PRC2 activity and permitting derepression of normally silenced inflammatory and cell cycle genes. Loss of H3K27me3 at tau kinase genes may contribute to MAPT hyperphosphorylation.^[6]

Huntington’s Disease

PRC2 dysfunction is a prominent feature of Huntington’s disease. Mutant huntingtin interacts with PRC2 components and redirects the complex to ectopic genomic loci in striatal neurons. This leads to inappropriate H3K27me3 deposition at neuronal identity genes while depleting H3K27me3 from Polycomb targets, causing a dual gain-loss epigenetic catastrophe.^[5]

Parkinson’s Disease

In Parkinson’s disease, alpha-synuclein aggregation sequesters EED-PRC2 from the nucleus, reducing nuclear H3K27me3. Dopaminergic neuron-specific EED targets, including genes controlling catecholamine biosynthesis and axonal maintenance, become derepressed inappropriately.^[7]

Cohen-Gibson Syndrome

Heterozygous missense mutations in EED cause Cohen-Gibson syndrome, a Weaver-like overgrowth disorder with intellectual disability, characteristic facial features, and advanced bone age. These mutations typically cluster in the H3K27me3-binding aromatic cage, disrupting allosteric activation.^[8]

Expression

EED is broadly expressed throughout the central nervous system with enrichment in neural progenitor zones during development. In the adult brain, EED maintains moderate expression in cortical pyramidal neurons, hippocampal neurons, striatal medium spiny neurons, and dopaminergic neurons of the substantia nigra. Expression gradually declines with aging, particularly in vulnerable neuronal populations.

Common Variants

Therapeutic Implications

• EED226/A-395: Allosteric PRC2 inhibitors that bind the EED aromatic cage; under investigation for cancer but inform structure-activity relationships for neurodegeneration^[9]

• PRC2 stabilizers: Small molecules that enhance EED-EZH2 interaction to boost declining PRC2 activity in aging neurons

• H3K27me3 mimetics: Synthetic peptides that activate the EED allosteric site to enhance PRC2 processivity

• Gene therapy: AAV-mediated EED supplementation in vulnerable neuronal populations to restore H3K27me3 levels

See Also

• SUZ12 — PRC2 core subunit](/genes)

• EZH2 — PRC2 catalytic subunit](/genes)

• JARID2 — PRC2 accessory subunit](/genes)

• BMI1 — PRC1 core subunit](/genes)

• RNF2 — PRC1 catalytic subunit](/genes)

• KDM6B — H3K27me3 demethylase (opposes PRC2)

External Links

• NCBI Gene: EED](/genes/eed)

• UniProt: O75530

• GeneCards: EED