RNA Polymerase |
Cellular Compartment |
Product of Transcription |
Function of RNAs |
||
I |
Nucleolus |
Most ribosomal RNAs ( rRNAs ) |
The rRNAs are components of the ribosome and are essential to the process of translation . |
||
II |
Nucleus |
All protein-coding pre-mRNAs |
Pre-mRNAs undergo extensive processing after transcription but before translation . |
||
III |
Nucleus |
5S-rRNA , small nuclear RNAs , and translational RNAs ( tRNAs ) |
Small nuclear RNAs splice pre-mRNAs and regulate transcription factors . The tRNAs decode mRNA to produce proteins . |