Which of the following processes is the initial event in the conversion of an hnRNA to the mature RNA?
A)formation of ribonucleoprotein particles (RNPs)
B)capping the 5'-end of the transcript with a guanylyl group by guanylyl transferase
C)addition of a poly(A)tail to the 3'-end of the transcript by poly(A)polymerase
D)transesterification reactions in lariat formation

Question

Quizplus · Accepted Answer

The capping of the 5'-end of the transcript with a guanylyl group by guanylyl transferase is the first step in the conversion of hnRNA to mature RNA. This cap protects the transcript from degradation by ribonucleases and facilitates translation initiation. The formation of RNPs, addition of a poly(A)tail, and transesterification reactions in lariat formation occur later in the RNA processing pathway.

Which of the Following Processes Is the Initial Event in the Conversion