Site-Specific Antibody Fragment Conjugates for Reversible Staining in Fluorescence Microscopy

Area of Science:

• Molecular life sciences
• Bioconjugation chemistry
• Immunofluorescence imaging

Background:

• Chemoselective reactions enable site-specific protein modification, advancing antibody conjugates.
• Antibody-oligonucleotide conjugates combine target specificity with sequence-encoded binding properties.
• Oligonucleotides like DNA and peptide nucleic acids (PNAs) offer reversible, sequence-specific interactions.

Purpose of the Study:

• To develop a site-specific conjugation strategy for antibody-oligonucleotides.
• To demonstrate the utility of these conjugates for reversible immunofluorescence imaging.
• To combine Tub-tag® technology with click chemistry for creating novel bioconjugates.

Main Methods:

• Utilized Tub-tag® technology and copper-catalyzed azide-alkyne cycloaddition (CuAAC).
• Performed site-specific conjugation of single DNA and PNA strands to an eGFP-binding nanobody.
• Demonstrated binding to recombinant eGFP and subsequent annealing of fluorescently labeled imager strands.

Main Results:

• Successfully generated antibody-oligonucleotide conjugates with site-specific DNA and PNA attachment.
• Showcased reversible staining of eGFP-tagged proteins in human cells.
• Validated the sequential and reversible imaging capabilities in a single specimen.

Conclusions:

• The developed conjugation strategy is suitable for creating antibody-oligonucleotides.
• This approach enables reversible immunofluorescence imaging of target proteins.
• Antibody-oligonucleotide conjugates represent a significant advancement for molecular life sciences research.