Ehmt1, also known as euchromatic histone lysine methyltransferase 1 or GLP, is a pivotal component of the epigenetic machinery. It primarily mediates histone 3 lysine 9 di-methylation (H3K9me2), as well as methylation of non-histone proteins, and is involved in transcriptional regulation, genome methylation, and DNA repair [1]. Dysregulation of Ehmt1 has been associated with various biological processes and diseases, highlighting its overall biological importance. Genetic models, such as KO/CKO mouse models, are valuable tools for studying its function.

In oogenesis, oocyte-specific conditional knockout mouse models (Ehmt1 cKO, Ehmt1/2 cDKO) revealed that loss of Ehmt1 recapitulated meiotic defects similar to those in Ehmt2 cKO. However, there was a more significant impairment in oocyte maturation and developmental competence in Ehmt1 cKO and Ehmt1/2 cDKO oocytes, leading to mid-gestation embryonic lethality upon fertilization. Multi-omics analyses showed that Ehmt1 contributes to local transcriptional repression in the oocyte, partially independent of Ehmt2 [3]. In alveolar rhabdomyosarcoma, suppression of Ehmt1 in a mouse xenograft model impaired cell motility, induced differentiation, and reduced tumor progression, suggesting its role in tumor progression and maintenance of cancer stem cell stemness [2].

In conclusion, Ehmt1 is crucial for epigenetic regulation, playing essential roles in oogenesis and cancer-related processes. The use of Ehmt1 KO/CKO mouse models has provided insights into its functions in these specific biological and disease-related contexts, contributing to a better understanding of the underlying molecular mechanisms [2,3].

References:

1. Nachiyappan, Alamelu, Gupta, Neelima, Taneja, Reshma. 2022. EHMT1/EHMT2 in EMT, cancer stemness and drug resistance: emerging evidence and mechanisms. In The FEBS journal, 289, 1329-1351. doi:10.1111/febs.16334. https://pubmed.ncbi.nlm.nih.gov/34954891/

2. Nachiyappan, Alamelu, Soon, Joshua Ling Jun, Lim, Huey Jin, Lee, Victor Km, Taneja, Reshma. 2022. EHMT1 promotes tumor progression and maintains stemness by regulating ALDH1A1 expression in alveolar rhabdomyosarcoma. In The Journal of pathology, 256, 349-362. doi:10.1002/path.5848. https://pubmed.ncbi.nlm.nih.gov/34897678/

3. Demond, Hannah, Hanna, Courtney W, Castillo-Fernandez, Juan, D'Santos, Clive S, Kelsey, Gavin. 2023. Multi-omics analyses demonstrate a critical role for EHMT1 methyltransferase in transcriptional repression during oogenesis. In Genome research, 33, 18-31. doi:10.1101/gr.277046.122. https://pubmed.ncbi.nlm.nih.gov/36690445/