Context:
Wave Life Sciences, a Massachusetts-based biotechnology company, made history by becoming the first to clinically test RNA editing as a treatment for a genetic disorder.
Central Dogma of Molecular Biology:
- DNA, the genetic material, contains the blueprint for life.
- Transcription: The cell transcribes this blueprint into mRNA, a molecular messenger.
- Translation: The mRNA is then translated into proteins, the workhorses of the cell.
- Errors in Transcription: Errors during transcription can lead to the production of faulty proteins, often linked to debilitating diseases.
Role of RNA:
- RNA Interference: A natural process where small RNA molecules can silence specific genes.
- CRISPR-Cas9: A powerful gene-editing technique, relies on RNA to guide the precise editing of DNA.
- mRNA Vaccines: mRNA vaccines, like those used for COVID-19, utilize mRNA to instruct cells to produce viral proteins, triggering an immune response.
- Rapid Development of mRNA Vaccines: The rapid development of mRNA vaccines during the pandemic highlights the versatility and potential of RNA-based technologies.
DNA vs. RNA:
- Nucleic acids are the molecules responsible for the inheritance of traits from one generation to the next.
- They are composed of two primary types: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
- DNA, characterized by its deoxyribose sugar, serves as the primary genetic material, storing and transmitting hereditary information.
- RNA, containing ribose sugar, plays crucial roles in protein synthesis, gene expression, and viral replication.
| Feature | DNA | RNA |
| Structure | Double-stranded helix | Single-stranded |
| Sugar | Deoxyribose | Ribose |
| Nitrogenous Bases | Adenine, Thymine, Guanine, Cytosine | Adenine, Uracil, Guanine, Cytosine |
| Function | Stores genetic information | Involved in protein synthesis, gene expression, and viral replication |
| Stability | More stable | Less stable |
| Location in Cell | Nucleus | Nucleus, cytoplasm, and ribosomes |
| Role in Protein Synthesis | Provides genetic code | Transcribes genetic code and translates it into proteins |
RNA editing vs. DNA editing:
| RNA Editing | DNA Editing |
| Temporary Changes: RNA editing induces temporary changes in RNA, allowing for potential reversibility and minimizing the risk of permanent genetic alterations. | Permanent Changes: DNA editing introduces permanent modifications to the genome, which can have irreversible consequences. |
| Lower Risk of Immune Reactions: RNA editing utilizes endogenous ADAR enzymes, which are naturally present in human cells, reducing the likelihood of immune responses. | Potential for Immune Reactions: DNA editing often employs bacterial proteins like Cas9, which can trigger immune reactions in some individuals. |
| Greater Flexibility: RNA editing offers more flexibility in terms of targeting specific RNA transcripts and modifying their function, providing a wider range of therapeutic possibilities. | Limited Flexibility: DNA editing is typically focused on precise gene modifications, offering less flexibility in terms of therapeutic approaches. |
Challenges in RNA editing:
- Specificity Challenge: ADAR enzymes can sometimes target unintended RNA sequences, potentially leading to harmful side effects. Scientists are working on improving the accuracy of targeting specific RNA sequences.
- Temporary Nature: While the temporary nature of RNA editing is advantageous, it necessitates repeated treatments to maintain therapeutic effects.
- Delivery Challenges: Current delivery methods, such as lipid nanoparticles and AAV vectors, have limitations in terms of carrying capacity, hindering the efficient delivery of larger RNA editing components.
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Source: The Hindu
Previous Year Question
‘RNA interference (RNAi)’ technology has gained popularity in the last few years. Why?
1. It is used in developing gene silencing therapies
2. It can be used in developing therapies for the treatment of cancer.
3. It can be used to develop hormone replacement therapies.
4. It can be used to produce crop plants that are resistant to viral pathogens.
Select the correct answer using the code given below.
[UPSC CSE – 2019 Prelims]
(a) 1, 2 and 4
(b) 2 and 3
(c) 1 and 3
(d) 1 and 4 only
Answer: (a)
