Final answer:
Template histones, such as H3-H4, can undergo chemical modifications that affect gene transcription. Acetylation of lysines near the amino end of H2B and H4 histones can unwind nucleosomes and promote transcription, while methylation of lysines or arginines of H3 and H4 histones can also increase DNA accessibility for transcription.
Step-by-step explanation:
Template histones, such as H3-H4, play a role in regulating gene transcription. Chemical modifications, such as acetylation and methylation, can occur on lysines and arginines of these histones. Acetylation of lysines near the amino end of histones H2B and H4 tends to unwind nucleosomes and open the underlying DNA for transcription. On the other hand, methylation of lysines or arginines of H3 and H4 can open DNA for transcription, while demethylation has the opposite effect.