Related Experiment Video
Updated: Jul 8, 2026
MicroRNA Amplification and Recognition through Locked-nucleic-acid In situ Hybridization as a Novel Detection and Quantification Method
Published on: October 7, 2025
In situ detection of precursor and mature microRNAs in paraffin embedded, formalin fixed tissues and cell
1Department of Pathology and the Comprehensive Cancer Center, Ohio State University Medical Center, 81 HLRI, 473 W 12th Avenue, Columbus, OH 43210, USA. gnuovomd@pol.net
Abstract:
The in situ detection of microRNAs (miRs) expression offers several challenges. It would be advantageous to have a method which can be used in paraffin embedded, formalin fixed tissue to be able to access the large data bank of archival material. Further, it would be helpful if one could differentiate between precursor and mature, active forms of the miR. In this review, two different methods for the in situ detection of miR in paraffin embedded, formalin fixed tissues are described. Detection of the inactive precursor miR can be accomplished by RT in situ PCR. This will allow the detection of one copy of a given pre-miR per cell. Detection of the mature form of a given miR can be accomplished with in situ hybridization with a labeled probe in which some of the nucleotides have been modified; this is referred to as a locked nucleic acid (LNA) probe. An intense signal after in situ detection with the LNA probe documents marked up-regulation of the, typically, mature miR. Further, one can easily determine the specific subcellular compartmentalization of the precursor and mature forms which may provide insight into the modulation of these important regulatory molecules and their targets.
Insights
This review details methods for detecting microRNAs (miRs) in archival tissues. Techniques differentiate precursor and mature miRs, aiding in understanding their roles in gene regulation.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- In situ detection of microRNAs (miRs) in formalin-fixed, paraffin-embedded tissues presents challenges.
- Accessing archival tissue banks requires reliable miR detection methods.
- Differentiating between precursor and mature microRNA forms is crucial for understanding gene regulation.
Purpose of the Study:
- To review methods for in situ detection of microRNAs in archival tissues.
- To describe techniques capable of distinguishing precursor and mature microRNA forms.
- To highlight the utility of these methods for studying miR expression and localization.
Main Methods:
- Reverse transcription in situ PCR (RT in situ PCR) for detecting inactive precursor microRNAs (pre-miRs) at single-copy sensitivity.
- In situ hybridization using locked nucleic acid (LNA) probes for detecting mature microRNAs.
- Utilizing modified nucleotides within LNA probes for enhanced detection.
Main Results:
- RT in situ PCR enables sensitive detection of pre-miRs in fixed tissues.
- LNA probes facilitate robust detection of mature miRs, indicating significant up-regulation.
- Both methods allow for the determination of subcellular localization of precursor and mature miRs.
Conclusions:
- Established methods allow for the in situ detection of both precursor and mature microRNAs in archival tissues.
- These techniques provide insights into microRNA processing, regulation, and subcellular compartmentalization.
- The described methods enhance the utility of formalin-fixed, paraffin-embedded tissues for microRNA research.
