mRNA, or messenger RNA, is a type of RNA that carries genetic information from DNA to the ribosome, where it serves as a template for protein synthesis.
🔑 Definition:
mRNA (messenger RNA) is a single-stranded RNA molecule transcribed from a DNA gene that contains the instructions to build a specific protein.
⚙️ What mRNA Does:
- Transcription (in the nucleus)
- DNA is used as a template to make an mRNA strand.
- This process is carried out by RNA polymerase II.
- The mRNA contains codons — sequences of three nucleotides that each specify an amino acid.
- Processing (in eukaryotes)
Before leaving the nucleus, the mRNA is:- Capped at the 5’ end (for stability and ribosome recognition)
- Spliced (introns are removed, exons joined)
- Polyadenylated at the 3’ end (poly-A tail for stability)
- Translation (in the cytoplasm)
- The mRNA travels to the ribosome.
- Ribosomes “read” the mRNA codons and assemble amino acids in the correct order to make a protein.
🧪 Key Features of mRNA:
| Feature | Role |
|---|---|
| Codons | Each 3-base codon codes for 1 amino acid |
| 5’ cap | Helps ribosome recognize and bind the mRNA |
| Poly-A tail | Protects mRNA from degradation |
| UTRs | (Untranslated regions) regulate translation efficiency |
🧠 Why mRNA Is Important:
| Area | Importance |
|---|---|
| Protein production | All cellular proteins are made by translating mRNA |
| Gene expression | mRNA levels reflect how active a gene is |
| Medical research | mRNA is a tool in vaccines, cancer therapy, and gene therapy |
| mRNA vaccines | (e.g., COVID-19 vaccines) deliver synthetic mRNA to instruct cells to make a harmless viral protein, triggering an immune response |
📌 Summary:
mRNA is the messenger molecule that carries genetic instructions from DNA to the ribosome, where proteins are made. It’s central to how genes are expressed and how the body builds everything from enzymes to structural components.