5 Which of the following statements regarding eukaryotic tra

5. Which of the following statements regarding eukaryotic transcription is FALSE?

a. RNA polymerase II has a critical carboxy-terminal domain that is phosphorylated during

active transcription.

b. General transcription factors are designated TFII followed by a number, and they function in initiation of transcription across the eukaryotic genome.

c. The most highly transcribed eukaryotic genes contain CpG islands upstream of their transcription start site rather than TATA boxes.

d. Distal enhancers, like promoter-proximal elements, are composed of several small, 6–10 bp functional sequence elements.

Solution

RNA polymerase II contains a unique 220 kd subunit called as carboxyl terminal domain (CTD). This domain is unique because it contains multiple repeats of YSPTSPS consensus amino acid sequences. The RNA polymerase can be regulated by the activity of phosphorylation on the serine residues of CTD.

The GC rich regions in the upstream of DNA sequences are called CpG islands and may contain transcription initiation site or restriction sites for some enzymes. The enhancer sequences are short sequences containing 6 - 10 nucleotides and are located distal to promoters or after promoter sequences.

The general transcription factors are designated asTF. The Roman number II denotes RNA polymerase II. The TFII is followed by alphabets like A,B and D etc but not the numbers.

General transcription factors are designated TFII followed by a number, and they function in initiation of transcription across the eukaryotic genome is FALSE. Option b is correct.