Question

There are three types of RNA pol III promoters (Type 1, Type 2, and Type 3). Two types have internal promoters and one has an upstream promoter. Which type has the upstream promoter?

A) No RNA pol III promoters are located upstream of the startpoint of transcription.
B) Type III
C) Type II
D) Type I

Answer 1

Type 3 RNA polymerase III promoters are the ones with an upstream promoter, making Type III (option B) the correct answer.

Step-by-step explanation:

When considering the three types of RNA polymerase III promoters in eukaryotes, Type 1 and Type 2 both have internal promoters.

In contrast, Type 3 RNA polymerase III promoters have an upstream promoter. As such, the correct answer to which RNA pol III promoter type has the upstream promoter is option B) Type III.

It's essential to note that genes transcribed by RNA polymerase III, such as 5S rRNA and tRNAs, usually involve unique promoter structures as compared to other RNA polymerases.

While Type 1 and Type 2 promoters are internal, meaning they are located within the transcribed sequence itself, Type 3 promoters are located upstream of the transcription start site.