Degradation of a eukaryotic mRNA is generally initiated by:
A)cleavage of the 5' end.
B)random cleavages throughout the mRNA strand.
C)shortening of poly(A)tail.
D)lengthening of poly(A)tail.
E)removal of the 5' cap.

Question

Quizplus · Accepted Answer

Eukaryotic mRNA degradation is usually initiated by shortening of the poly(A) tail, which enables deadenylase enzymes to access the mRNA and begin the process of degradation. This is followed by decapping and exonucleolytic digestion of the mRNA strand from the 5 end. Random cleavages throughout the mRNA strand are not a typical initiation mechanism. Lengthening of the poly(A) tail would actually stabilize the mRNA, and removal of the 5 cap would prevent translation initiation but not necessarily initiate degradation.

Degradation of a Eukaryotic MRNA Is Generally Initiated By