Which of the Following Can Be Used to Express a Second

Question

Which of the following can be used to express a second transgene from a single mRNA?
A) Downstream AUG.
B) IRES
C) Alternative mRNA splicing signals.
D) RNA editing sequences
E) All of the above.

Accepted Answer

IRES (Internal Ribosome Entry Site) is a sequence that allows translation initiation in the middle of an mRNA sequence, independent of the 5' cap. This allows for expression of a second transgene from a single mRNA. Downstream AUG and alternative mRNA splicing signals do not necessarily provide this capability, and RNA editing sequences alter the sequence of an mRNA, rather than affecting its translation. Therefore, the correct choice is B (IRES).