You are examining the process of RNA synthesis in a cell line derived from a pancreatic tumor. You discover that the cells do not contain any U1 small nuclear RNA (snRNA). The lack of this RNA species in these cells is most likely to have which of the following effects on overall RNA synthesis?
A) defective polyA tail addition
B) failure of capping mRNAs
C) loss of intron splicing
D) no synthesis of any mRNAs
E) synthesis of only rRNAs

Question

Quizplus · Accepted Answer

U1 snRNA is a component of the spliceosome, which is essential for the splicing of introns from pre-mRNA. Without U1 snRNA, intron splicing cannot occur properly.  Nuclear mRNA introns undergo a splicing reaction catalyzed by specialized RNA-protein complexes called small nuclear ribonucleoprotein particles (snRNPs, pronounced snurps). The RNAs found in snRNPs are identified as U1, U2, U4, U5, and U6. Lack of the U snRNPs would lead to a failure to properly splice mRNAs.

You Are Examining the Process of RNA Synthesis in a Cell