RNA polymerase III is not responsible for the transcription of:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → hnRNA
A eukaryote has three RNA polymerases in the nucleus, and each one transcribes different RNAs. RNA polymerase I makes the large rRNAs (28S, 18S and 5.8S). RNA polymerase II makes hnRNA, the precursor of mRNA. RNA polymerase III makes tRNA, 5S rRNA and snRNAs.
(1) snRNA — Transcribed by RNA polymerase III.
(2) tRNA — Transcribed by RNA polymerase III.
(3) hnRNA — Not transcribed by RNA polymerase III. It is the heterogeneous nuclear RNA, the precursor of mRNA, and it is transcribed by RNA polymerase II.
(4) 5S rRNA — Transcribed by RNA polymerase III. The larger rRNAs, by contrast, are made by RNA polymerase I.
Note: A similar question was also asked in CUET (UG) 2023 on 12-06-2023 (Slot 2).
NCERT Extract:
Types of RNA and the Process of Transcription – “… There are at least three RNA polymerases in the nucleus (in addition to the RNA polymerase found in the organelles). There is a clear cut division of labour. The RNA polymerase I transcribes rRNAs (28S, 18S, and 5.8S), whereas the RNA polymerase III is responsible for transcription of tRNA, 5srRNA, and snRNAs (small nuclear RNAs). The RNA polymerase II transcribes precursor of mRNA, the heterogeneous nuclear RNA (hnRNA).”