Recently, a biotechnology company in Massachusetts in the U.S. named Wave Life Sciences made headlines for becoming the first company to treat a genetic condition by editing RNA at the clinical level.
About RNA Editing
- Cells synthesise messenger RNA (mRNA) using instructions in DNA and then ‘read’ instructions from the mRNA to make functional proteins.
- During this process of transcription, the cell may make mistakes in the mRNA’s sequence and based on it produce faulty proteins.
- Many of these proteins have been known to cause debilitating disorders. RNA editing allows scientists to fix mistakes in the mRNA after the cell has synthesised it but before the cell reads it to make the proteins.
- One technique involves a group of enzymes called adenosine deaminase acting on RNA (ADAR). Adenosine is one of the building blocks of RNA.
- ADAR works by converting some of the adenosine blocks in mRNA to another molecule called inosine. This is useful because inosine mimics the function of a different RNA building block called guanosine.
- Because guanosine-like function is found where adenosine is supposed to be, the cell detects a mistake and proceeds to correct it, in the process restoring the mRNA’s original function. And then the cell makes normal proteins.
- In its therapy, dubbed WVE-006, the company used a gRNA to lead ADAR enzymes to specific single-point mutations in the mRNA sequence of the SERPINA1 gene, which contains the instructions for cells to make α-1 antitrypsin.
RNA editing and DNA editing
- DNA editing makes permanent changes to a person’s genome and sometimes this can lead to irreversible errors. On the other hand, RNA editing makes temporary changes, allowing the effects of the edits to fade over time.
- CRISPR-Cas9 and other DNA editing tools require proteins acquired from certain bacteria to perform the cutting function, but these proteins can elicit undesirable immune reactions in some cases. RNA editing relies on ADAR enzymes, which already occur in the human body and thus present a lower risk of allergic reactions.
(The Hindu)
