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Updated: Jun 13, 2025
Author Spotlight: Detection of Mitophagy in Caenorhabditis elegans and Mammalian Cells Using Organelle-Specific Dyes
Published on: May 19, 2023
A FRET biosensor constructed using pH sensitive G-quadruplex DNA for detecting mitochondrial autophagy
Dawei Yang1, Ranran Sun1, Hongxia Sun1
1Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Researchers developed a novel pH-responsive oligonucleotide biosensor that targets mitochondria. This tool accurately detects mitochondrial autophagy (mitophagy) in live cells by utilizing a G-quadruplex structure and FRET technology.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Mitochondria are vital organelles for cellular energy production and physiological functions.
- Monitoring mitochondrial health, particularly through mitophagy, is crucial for identifying cellular dysfunction.
- Existing methods for mitophagy detection often lack specificity or require complex procedures.
Purpose of the Study:
- To develop a novel, highly specific optical biosensor for monitoring mitophagy in live cells.
- To engineer a pH-responsive oligonucleotide with unique targeting capabilities for mitochondria.
Main Methods:
- Design and synthesis of a pH-responsive G-quadruplex (G4) oligonucleotide (P24) with specific guanine-rich sequences.
- Characterization of P24's structural transitions at different pH levels (lysosomal vs. mitochondrial).
- Construction of a Förster Resonance Energy Transfer (FRET) based biosensor by conjugating P24 with fluorophores.
- Validation of the biosensor's performance in detecting mitophagy in live cellular models.
Main Results:
- P24 forms a stable G4 structure at lysosomal pH (4.5) and transitions to a double-stranded form at mitochondrial pH (7.4).
- The P24-based biosensor exhibits selective accumulation in mitochondria, unlike typical lysosomal oligonucleotides.
- The FRET-based biosensor effectively detects mitophagy in real-time within live cells.
Conclusions:
- The P24 oligonucleotide serves as a robust platform for creating pH-responsive mitochondrial biosensors.
- This novel biosensor enables precise and reliable monitoring of mitophagy, offering a valuable tool for studying mitochondrial dynamics and diseases.
