12. Which of the following is NOT a mechanism of action of transcriptional co-activator proteins? a. binding TATA box elements to direct RNA polymerase binding b. histone tail acetylation c. chromatin remodeling d. mediating contact between activation domains and the RNA polymerase enzyme Solution Ans.) \"a\" Binding of TATA box elements to RNA polymerase is not a mechanism of action of transcriptional co-activator proteins..