Fluorescent Oligonucleotide Ligation
Fluorescent Oligonucleotide Ligation - Related Videos
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Proximity Ligation Assay to Study In Situ Protein-Protein Interactions
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This video describes the proximity ligation assay to study in situ protein-protein interactions in nematode cells. The close proximity of the proteins of interest generates the circular DNA template with the help of a PLA probe attached to a secondary antibody. The probe is further amplified using the amplification solution, which produces a long single-stranded DNA followed by the hybridization of the detector probe, enabling the localization of protein-protein interactions in cells.
FAQs
The two oligonucleotides must hybridize next to one another on the same complementary template so the ligase can recognize a properly aligned junction. This arrangement links sequence recognition to bond formation: a suitable match supports ligation, whereas an unfavorable junction is less likely to produce the corresponding product. The design therefore converts local sequence complementarity into a detectable assay outcome.
A mismatch near the ligation junction can disrupt the alignment required for efficient bond formation. Because the fluorescent signal depends on the formation or detection of the ligated product, sequence differences may produce a weaker or absent signal compared with a correctly matched target. This property enables discrimination of some sequence variants, including selected mutations or genotype-associated differences.
Fluorescent labels provide the measurable readout after probe hybridization and ligation. Depending on assay design, fluorescence associated with the probes or ligation products can be examined by imaging or fluorescence-based analysis. The signal indicates whether the expected molecular event occurred, allowing researchers to translate sequence-dependent ligation into an observable result rather than relying only on direct molecular inspection.
A typical workflow begins by combining sequence-specific oligonucleotides with a complementary DNA or RNA template. The probes hybridize at adjacent positions, and ligase is given the opportunity to form the covalent junction when alignment is suitable. Fluorescent labeling then supports detection of the probes or products through imaging or fluorescence-based analysis, producing an interpretable signal for the target sequence.
The method is useful when the assay must distinguish a target sequence from a closely related variant. Probe sequences can be selected so that ligation depends on matching at the relevant junction, while fluorescence supplies the readout. In biological research, this supports genotyping and mutation detection by connecting sequence-specific recognition with a measurable signal that can be compared across samples.
Fluorescent oligonucleotide ligation can provide evidence for the presence of a target sequence, the presence of selected sequence variants, or the success of a sequence-dependent ligation event. Its compatibility with DNA and RNA templates broadens its use in sequence analysis and sensitive nucleic acid assays. Researchers can then interpret fluorescence through imaging or other fluorescence-based measurements.