Final answer:
Methylation of cytosine bases and the modification of histone proteins like acetylation and methylation are integral to epigenetic regulation, a process that influences gene expression without altering the DNA sequence. Such epigenetic changes can be heritable and reversible, which is significant in understanding the regulation of genes, including those silenced in cancer.
Step-by-step explanation:
Methylation of cytosine bases and the post-translational modification of histone proteins are processes associated with epigenetic regulation. These modifications play crucial roles in the control of gene expression. Epigenetic regulation involves chemical changes to DNA or histones that affect the way genes are read by cells and can influence phenotypes without altering the underlying genetic code.
The best-known form of DNA modification is DNA methylation, typically occurring at CpG islands, mainly in promoter regions, leading to gene silencing or altered gene expression. Histone modifications including acetylation, methylation, and phosphorylation can also impact gene expression. These modifications change the accessibility of DNA to transcription machinery, either promoting or inhibiting the transcription of associated genes.
In cancer cells, abnormal epigenetic changes such as hyper methylation of DNA and deacetylation of histones contribute to gene silencing. The reversible nature of these modifications has implications for potential cancer treatments by reactivating silenced genes through epigenetic therapy.
Environmental factors, like UV rays, or certain proteins like RNA binding proteins can also influence epigenetic states through various modifications, like phosphorylation, which can in turn affect gene expression.