Final answer:
The main function of methylation and acetylation in PTMs is to regulate gene expression, which can affect transcription, DNA accessibility, and chromatin structure. These modifications are crucial for cellular responses to environmental stimuli and have implications in cancer treatment, as they can inform targeted therapies. Option B is correct.
Step-by-step explanation:
The main function of methylation and acetylation, alongside other post-translational modifications (PTMs), is B) to regulate gene expression. Methylation and acetylation modifiers such as histone acetyltransferases (HAT enzymes) and methyl transferases play a critical role in altering chromatin structure, thereby affecting gene transcription.
For example, acetylation typically unwinds nucleosomes, making the underlying DNA more accessible for transcription, while methylation can have varying effects on gene expression depending on the site of methylation. Other PTMs can influence protein function in multiple ways, such as altering protein stability, localization, and interactions with other molecules.
New drugs that decrease DNA methylation and inhibit the removal of acetyl groups from histone proteins are being developed as targeted therapies to alter gene expression and potentially kill tumor cells. In cancer, understanding the patterns of gene expression and regulation through PTM can provide insights into the mechanisms of cancer progression and opportunities for targeted treatment.