DNA METHYLATION & EPIGENETIC REGULATION: CPG ISLANDS, DNMTS, TET ENZYMES & METHYLATION PATTERNS 🎗
“DNA methylation is an epigenetic mark” involved in regulating transcription and maintaining cellular identity. -Dr. Peter A. Jones 🧬 DNA methylation is an epigenetic mechanism regulating gene activity without changing the DNA sequence. Most commonly, a methyl group is added to the 5-carbon of cytosine within 5′-CpG-3′ dinucleotides, forming 5-methylcytosine (5mC). It contributes to transcriptional regulation, cellular differentiation, genomic stability, development, genomic imprinting and cell identity. 🔹 CpG islands are GC- and CpG-rich regions, often near gene promoters. Many promoter-associated CpG islands remain unmethylated when genes are active, whereas aberrant promoter methylation can contribute to transcriptional repression through altered regulatory-factor binding and recruitment of chromatin-remodelling proteins. Importantly, methylation is context-dependent: its effects vary across promoters, enhancers, gene bodies and repetitive elements. 🔹 DNMTs are the pr...