### EZH1 Gene Overview

**Gene Symbol**: EZH1  
**Protein Summary**: EZH1 is a Polycomb group (PcG) protein that serves as a catalytic subunit of the PRC2/EED-EZH1 complex. It is responsible for the methylation of lysine 27 on histone H3 (H3K27), a modification that leads to transcriptional repression of target genes. EZH1 is capable of mono-, di-, and trimethylating H3K27, resulting in the formation of H3K27me1, H3K27me2, and H3K27me3, respectively. Additionally, EZH1 plays a role in the maintenance of embryonic stem cell identity and self-renewal, though its function is less pivotal than that of the closely related EZH2 protein.

### 1. Associated Genes
EZH1 is known to interact with a variety of gene products and regulatory factors, which may include:

- **EZH2**: The closely related homolog that has a more prominent role in the PRC2 complex.
- **SUZ12**: Another component of the PRC2 complex that stabilizes EZH1/2 and aids in methylation activity.
- **EED**: Essential for the assembly and stabilization of the PRC2 complex.

While these interactions were mentioned, additional genes that may be associated through regulatory networks or disease contexts include:

- **ASXL1**: Associated with the function of the PRC2 complex in gene silencing.
- **BMI1**: Interacts with the PcG proteins for gene repression.

### 2. Aging and Age-Related Diseases
EZH1 has been implicated in various processes related to aging and age-related diseases:

- **Cancer**: Aberrant expression and mutations in EZH1 have been observed in multiple cancers, including leukemia and solid tumors. The role of EZH1 in tumorigenesis can be linked to its influence on gene expression and cell identity.
- **Neurodegenerative Diseases**: Since EZH1 is involved in epigenetic regulation and cellular identity, alterations in its expression may contribute to the pathophysiology of diseases like Alzheimer's disease through dysregulation of gene networks critical for neuronal function.

### 3. Drug Interactions
Drugs targeting the EZH1/PRC2 complex are of interest, especially in the context of cancer therapy. Known drug classes and specific compounds that interact with EZH1 include:

- **EZH2 Inhibitors**: These are in development, as there may be overlapping functions with EZH1. Examples include:
  - GSK126
  - EPZ6438
- **Histone Modifiers**: Some small molecules that affect histone methylation and acetylation may indirectly modulate EZH1 activity by altering the epigenetic landscape.

### 4. Pathways and Biological Processes
EZH1 is involved in various biological processes and signaling pathways, including:

- **Histone Modification**: Primarily through tri-methylation at H3K27, influencing chromatin structure and gene expression.
- **Regulation of Transcription**: Plays a significant role in transcriptional repression, contributing to developmental gene regulation, particularly in stem cells.
- **Developmental Biology**: Essential for maintaining pluripotency and lineage specification in embryonic stem cells.
- **Polycomb Repressive Complex Pathway**: Functions as part of the PRC2 complex, which is integral to the epigenetic regulation of gene expression.

### Conclusion
EZH1 is a critical gene involved in epigenetic regulation through the PRC2 complex, with implications in development, stem cell biology, and cancer. Ongoing research may further elucidate its roles in aging and potential therapeutic applications.