複選題6. Choose the descriptions which are NOT CORRECT: (A) DNA methylation on the promoter region is commonly associated with downregulation of gene expression. (B) Promoter is a region at the gene where the transcriptional machinery binds. (C) Enhancers are the units of regulatory sequences which spread thousands of nucleotides from only the upstream of promoter. (D) Insulators are found between enhancers and some promoters to block activation of the promoter by activators. (E) The function of histone acetyl transferases is adding acetyl groups to histones tails, allowing the histones to wrap the DNA more tightly.