Universal drag tag for direct quantitative analysis of multiple microRNAs

Area of Science:

• Biochemistry
• Molecular Biology
• Analytical Chemistry

Background:

• Accurate measurement of multiple microRNAs (miRNAs) is crucial for their use as disease biomarkers.
• Direct quantitative analysis of multiple miRNAs (DQAMmiR) uses hybridization and capillary electrophoresis (CE) for miRNA detection.
• Separation in DQAMmiR relies on mobility modifiers like single-strand DNA binding protein (SSB) and drag tags.

Purpose of the Study:

• To experimentally validate the use of short peptides as extendable drag tags for DQAMmiR.
• To assess the efficacy of DNA-peptide probes in separating and quantifying multiple miRNAs.
• To refine theoretical models of probe mobility based on experimental data.

Main Methods:

• Conjugation of fluorescently labeled DNA probes with peptides of varying lengths (5-20 amino acids).
• Analysis of five specific miRNAs (mir10b, mir21, mir125b, mir145, mir155) using DQAMmiR with DNA-peptide probes.
• Capillary electrophoresis (CE) separation in both pure buffer and cell lysate, with SSB as a mobility modifier.

Main Results:

• Peptide tags successfully facilitated the separation of miRNA-DNA hybrids without interfering with SSB binding.
• The mobility shifts induced by peptide tags allowed for differential migration of the five analyzed miRNA hybrids.
• Experimental data supported theoretical predictions and enabled refinement of mobility models.

Conclusions:

• DNA-peptide probes are effective and practical for DQAMmiR, offering a universal extendable drag tag.
• This method can be extended for the simultaneous analysis of more than 10 miRNAs.
• The findings advance miRNA quantification techniques for disease diagnostics.