<P> Histone methylation is a process by which methyl groups are transferred to amino acids of histone proteins that make up nucleosomes , which the DNA double helix wraps around to form chromosomes . Methylation of histones can either increase or decrease transcription of genes , depending on which amino acids in the histones are methylated , and how many methyl groups are attached . Methylation events that weaken chemical attractions between histone tails and DNA increase transcription , because they enable the DNA to uncoil from nucleosomes so that transcription factor proteins and RNA polymerase can access the DNA . This process is critical for the regulation of gene expression that allows different cells to express different genes . </P>
<P> Histone methylation is a process by which methyl groups are transferred to amino acids of histone proteins that make up nucleosomes , which the DNA double helix wraps around to form chromosomes . Methylation of histones can either increase or decrease transcription of genes , depending on which amino acids in the histones are methylated , and how many methyl groups are attached . Methylation events that weaken chemical attractions between histone tails and DNA increase transcription , because they enable the DNA to uncoil from nucleosomes so that transcription factor proteins and RNA polymerase can access the DNA . This process is critical for the regulation of gene expression that allows different cells to express different genes . </P>
what regulates the packing of dna into chromosomes
what regulates the packing of dna into chromosomes
Methylation of histones
Methylation of histones