What happens to the transcript RNA before it leaves the nucleus?

What happens to the transcript RNA before it leaves the nucleus?

• A. 5' cap only
• B. No processing
• C. Translation occurs
• D. 5' cap, 3' poly-A tail, splicing

Answer: (D)

RNA transcripts in eukaryotes must be processed before they exit the nucleus. The transcript receives a 5' cap, a 3' poly-A tail, and undergoes splicing to remove introns and join exons. The 5' cap protects the RNA from degradation and helps ribosomes recognize it for translation. The 3' poly-A tail increases stability, aids export from the nucleus, and enhances translation efficiency. Splicing creates a mature, continuous coding sequence by removing noncoding introns. Translation, however, happens in the cytoplasm after the mRNA has been exported, not inside the nucleus. So the processing that prepares the transcript for export includes the 5' cap, the 3' poly-A tail, and splicing.

RNA transcripts in eukaryotes must be processed before they exit the nucleus. The transcript receives a 5' cap, a 3' poly-A tail, and undergoes splicing to remove introns and join exons. The 5' cap protects the RNA from degradation and helps ribosomes recognize it for translation. The 3' poly-A tail increases stability, aids export from the nucleus, and enhances translation efficiency. Splicing creates a mature, continuous coding sequence by removing noncoding introns. Translation, however, happens in the cytoplasm after the mRNA has been exported, not inside the nucleus. So the processing that prepares the transcript for export includes the 5' cap, the 3' poly-A tail, and splicing.