To Ensure the Fidelity of Splicing, the Spliceosome

Question

To ensure the fidelity of splicing, the spliceosome...
A) hydrolyzes ATP to undergo complex rearrangements.
B) examines the splicing signals on the pre-mRNA several times.
C) assembles on the pre-mRNA co-transcriptionally.
D) takes advantage of "exon definition."
E) All of the above.

Accepted Answer

The spliceosome uses ATP hydrolysis to produce a series of rearrangements, allowing the splicing signals to be checked and rechecked to ensure the accuracy of the process. The fact that splicing is coupled to transcription provides an advantage and helps the cell keep track of the exons, as does exon definition by SR proteins and other factors that mark the splice sites around each exon.