Final answer:
Nucleosome remodeling is an essential biological process involving chemical modifications of DNA and histones that regulate gene expression. Alterations in this process can lead to various diseases, including cancer.
Step-by-step explanation:
Nucleosome remodeling refers to the dynamic changes in chromatin structure that affect how DNA interacts with various proteins, particularly histones. This process can involve the alteration in methylation patterns on DNA and histones, as well as the use of ATP-dependent chromatin remodeling complexes that reposition nucleosomes. Chemical modifications such as acetylation, methylation, and phosphorylation can affect the spacing of nucleosomes and thereby regulate gene expression. For example, acetylation of histones tends to relax DNA-histone interactions, making DNA more accessible for transcription, while deacetylation and certain methylation patterns can condense chromatin and thereby repress gene expression. These epigenetic modifications are critical for normal cellular function; aberrations in these processes can contribute to diseases such as cancer.