QUESTION 1

The oocytes of multicellular animals contain stored mRNAs that
encode numerous proteins required for early embryonic development.
These proteins, however, are not translated until after
fertilization and, therefore, a mechanism must be in place to
ensure the stored mRNAs remain intact and untranslated before they
are needed. Which of the following is a mechanism that keeps these
stored mRNAs from being translated in the oocyte? Select
all correct answers.

A) Short poly(A) tails can bind only a few molecules of
cytoplasmic poly(A)-binding protein (PABPI), which is not enough to
interact with the initiation factor eIF4G.

B) Stored mRNAs in oocytes have short poly(A) tails, consisting
of ~20–40 residues.

C) PABPI interaction with eIF4G provides the stability that the
complex needs to initiation translation.

D) Short poly(A) tails can bind only a few molecules of
cytoplasmic poly(A)-binding protein (PABPI), which targets the mRNA
to the cytoplasmic exosome.

QUESTION 2

Which of the following statements about mRNA stability is
FALSE?

A) Deadenylation-independent mRNA decay is exclusively in the 5′
to 3′ direction.

B) Yeast mRNA decay occurs primarily in the 5′ to 3′ direction,
while 3′ to 5′ decay is more common in mammalian cells.

C) Decapping enzymes are required for all pathways of mRNA
decay.

D) The most common pathway of mRNA decay is
deadenylation-dependent.