Circular RNA (circRNA) has become a “new favorite” of gene regulation for several key reasons, reflecting its unique structural, functional, and therapeutic potential:
1. Structural Stability
Unlike linear RNA, circRNA forms a covalently closed loop structure via back-splicing, which makes it highly resistant to exonucleases. This stability leads to longer half-lives in cells, enhancing their functional durability and making them ideal for gene regulation and biomarker discovery.
2. Abundance and Widespread Presence
circRNAs are not rare anomalies; they are widely expressed in various organisms, tissues, and developmental stages. Advances in sequencing technologies have revealed that circRNAs are abundant in eukaryotic cells, suggesting they have biologically significant roles.
3. Regulation of Gene Expression
- miRNA Sponges: CircRNAs can act as “sponges” to sequester microRNAs (miRNAs), reducing their ability to suppress target mRNAs. For instance, CDR1as circRNA can bind miR-7, regulating its downstream effects.
- Protein Scaffolds: CircRNAs can interact with RNA-binding proteins (RBPs) to form scaffolds, regulating protein localization or activity.
- Transcriptional Regulation: Some circRNAs can influence transcriptional output by interacting with chromatin or transcription factors.
4. Diverse Functional Roles
CircRNAs participate in:
- Cell differentiation and development: CircRNAs can influence stem cell fate and tissue development.
- Pathological processes: CircRNAs are implicated in cancers, cardiovascular diseases, neurological disorders like Alzheimer’s, and immune responses.
5. Potential as Biomarkers and Therapeutics
- Biomarkers: Due to their stability and disease-specific expression, circRNAs are excellent candidates for biomarkers in cancer diagnosis, prognosis, and treatment response.
- Therapeutics: CircRNAs could be engineered for therapeutic applications, such as acting as miRNA sponges or templates for protein translation.
6. Circular RNA Translation
Emerging evidence shows that some circRNAs can act as templates for protein translation, expanding their roles beyond non-coding regulation. These circRNA-derived proteins may have functional significance in various biological processes.
Conclusion:-
Circular RNA represents a paradigm shift in RNA biology. Its unique structure, stability, and versatile regulatory functions have positioned it at the forefront of gene regulation research. Ongoing studies exploring its roles in disease and potential therapeutic applications continue to uncover the profound implications of circRNA in modern molecular biology.
