In 2024, Ambros and Ruvkun won the Nobel Prize in Medicine and Physiology for the discovery of the role of microRNAs in gene regulation in humans.

Gene expression is a process that involves the transcription and translation of genetic information into functional proteins. However, not all genes are expressed constantly, and their regulation is crucial for the development, growth and maintenance of living beings.

MicroRNAs (miRNAs) play a key role in the regulation of gene expression. These small non-coding RNAs, approximately 20-25 nucleotides in length, bind to specific mRNA (messenger ribonucleic acid) sequences and regulate their translation into proteins.

Regulation of gene expression by microRNAs is a highly specific and efficient process that allows cells to respond rapidly to changes in their environment and adapt to new conditions. In this process, miRNAs can act as repressors or activators of gene expression, depending on the sequence and context in which they are found.

The synthesis of microRNAs (miRNAs) occurs both in the nucleus and in the cytoplasm, starting with a transcription of DNA to RNA by polymerase II or III, thus forming the pri-microRNA, a structure that forms a double strand, subsequently, this is processed to give way to a precursor molecule called pre-microRNA which is characterized by a shorter length. This is passed to the cytoplasm by a protein. Once in the cytoplasm, RNase III or Dicer processes the pre-microRNA and double-stranded or duplex microRNAs (ds-microRNA) of between 21 and 24 nucleotides are obtained (Mendoza & Aviña; 2025).

Its importance lies in the control it has over gene expression, since a single microRNA can have several target messenger RNAs that control a large number of genes, this is achieved by recognizing the sequence, i.e. the microRNA is responsible for recognition and Ago2 determines which will be the mode of action, depending on which regulatory proteins are recruited to the complex. Once these recognize and bind to the messenger RNA, they can hinder translation, potentiate its translation or its degradation, indicating that these modulate the stability and translation of messenger RNAs, influencing the development and functioning of various systems in multicellular organisms (Matsuyama H & Suzuki; 2019).

This process reflects how microRNAs can regulate and modify fundamental cellular processes such as cell proliferation, differentiation and even apoptosis, opening new medical therapeutic possibilities such as biomarkers involved in insulin resistance leading to diseases such as diabetes, cancer and pancreatic β-cell dysfunction, demonstrating that they may have a great scope for medical diagnostics and personalized medical therapies.

Bibliography

• Matsuyama H, Suzuki HI. Systems and Synthetic microRNA Biology: From Biogenesis to Disease Pathogenesis. Int J Mol Sci. 2019 Dec 24;21(1):132. doi: 10.3390/ijms21010132. PMID: 31878193; PMCID: PMC6981965.
• Rojas Andrade, M. V. (2024). Micro-arns in the diagnosis of rheumatoid arthritis: a systematic review.
• Gonzalo, L. (2024). Study of the coupling between transcription and processing of microRNAs in plants.