複選題27. Modifications of histone tails control chromatin configurations and functions. Which of the following statement(s) about histone modifications is/are correct? (A) Histone H3 and H4 can be acetylated at multiple lysine sites (B) lysine acetylations of Histone H3 and H4 correlate with open chromatin configuration called euchromatin and favor active gene transcription. (C) Histone H3 and H4 can be mone-, di-, or tri-methylated at multiple lysine sites (D) Methylations of histone tails always associate with close chromatin configuration (E) Methylations of histone tails always result in gene silencing. Methylations of histone tails are seen in the promoter and gene body regions of genes that are no longer active in differentiated cells during development.