Question

You are investigating a mutant eukaryotic cell line that makes all of its mRNAs much longer than the mRNAs from normal cells. Intrigued, you examine the proteins in these cells and note that many of them are either much longer or much shorter than the normal proteins from nonmutant cells. Assuming there is just one mutant defect in these cells, which of the possibilities is most likely?

A stop codon is mutated
The enzyme that adds the poly-A tail is defective.
RNA polymerase does not recognize the terminator sequence.
The spliceosome is nonfunctional.
The release factor is defective.

Answer 1

The correct answer is that the spliceosome is non-functional.

Step-by-step explanation:

A spliceosome refers to a composite and large molecular apparatus found mainly inside the nucleus of the eukaryotic cells. The prime function of the spliceosome is to remove the introns from a transcribed pre-mRNA, that is, a kind of primary transcript.

In case if the spliceosome machinery gets failed to function, the mRNA will not remove the introns, that is, the non-coding parts and retains it. This will eventually lead to the formation of longer mRNAs.