You are characterizing the expression of a gene suspected of causing a form of ovarian cancer. You have isolated the gene and found that it is approximately 35 kilobases (kb) in length. Transcriptional analysis reveals that there are several discrete mRNAs produced by this gene ranging in length from 2.0 to 5.5 kb in normal and cancerous cells. Which of the following processes is the most likely cause of the difference in size of the mRNAs produced by this gene?
A) poly(A) addition
B) posttranslational modification
C) recombination
D) RNA editing
E) splicing

Question

Quizplus · Accepted Answer

The difference in size of the mRNAs is most likely due to splicing, where introns are removed and exons are joined in different combinations, resulting in mRNAs of varying lengths.  The precise splicing outcome of a transcribed gene is controlled by complex interactions between cis-regulatory splicing signals and trans-acting regulators. Alternative splicing is a prevalent mechanism for generating transcriptome and proteome diversity. Alternative splicing can modulate gene function, affect organismal phenotype, and cause disease.

You Are Characterizing the Expression of a Gene Suspected of Causing