複選題14. Which of the following statements in regard to transcription of messenger RNA (mRNA) are CORRECT ? (A) mRNA is transcribed by RNA polymerase II. (B) Transcription factors are proteins that bind to the promoter and regulate mRNA transcription. (C) The RNA polymerase II promoter can be located at both the upstream and downstream of the transcription start site. (D) RNA polymerase II requires general transcription factors (called TFIIX) to initiate transcription. (E) RNA polymerase II can be inhibited by low concentrations of alpha-amanitin.