Question

Which eukaryotic RNA polymerases have at least some promoters that are located upstream of the startpoint of transcription?

A) III
B) I and II
C) II only
D) I and III
E) I, II, and III

Answer 1

Eukaryotic RNA polymerases I, II, and III have at least some promoters that are located upstream of the start point of transcription.

Step-by-step explanation:

Eukaryotic RNA polymerases I, II, and III have at least some promoters that are located upstream of the start point of transcription.

For example, RNA polymerase I transcribes genes that have two GC-rich promoter sequences in the -45 to +20 region. These sequences alone are sufficient for transcription initiation, but further enhance initiation when additional sequences are present from -180 to -105 upstream of the initiation site.

RNA polymerase II, on the other hand, transcribes all protein-coding genes and has a more complex promoter structure, including a TATA box sequence and additional upstream sequences

Lastly, RNA polymerase III transcribes genes such as rRNA, tRNA, and small nuclear RNA, and these genes have upstream promoters or promoters that occur within the genes themselves.