RNA is broken down through a process called RNA degradation, which is primarily mediated by enzymes known as nucleases.
Nucleases and RNA Degradation
Nucleases are enzymes that cleave the phosphodiester bonds within nucleic acids, including RNA. There are three main types of nucleases involved in RNA degradation:
- 5' Exonucleases: These enzymes digest RNA from the 5' end. They remove nucleotides one by one, moving along the RNA molecule in a 5' to 3' direction.
- 3' Exonucleases: These enzymes digest RNA from the 3' end. Similarly, they remove nucleotides one by one, but in a 3' to 5' direction.
- Endonucleases: Unlike exonucleases, endonucleases cleave the RNA molecule internally, breaking the phosphodiester bonds within the RNA sequence. This creates smaller RNA fragments that can then be further degraded by exonucleases.
Process Summary
In summary, RNA degradation involves:
- Endonucleases making internal cuts within the RNA molecule.
- Exonucleases (both 5' and 3') then digesting the resulting fragments from their ends.
This coordinated action ensures that RNA molecules are efficiently broken down into their constituent nucleotides.
