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Intra Q-body: an antibody-based fluorogenic probe for intracellular proteins that allows live cell imaging and
Yancen Dai1, Yuko Sato2, Bo Zhu3
1Graduate School of Life Science and Technology, Tokyo Institute of Technology Nagatsuta-cho Yokohama Kanagawa 226-8503 Japan.
Chemical Science
|September 12, 2022
Summary
Researchers developed a novel Quenchbody (Q-body) probe for precise imaging of intracellular p53 (a tumor suppressor) in living cells. This breakthrough minimizes background noise, enabling clearer visualization and live-cell sorting based on p53 expression.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Intracellular biomarker imaging using fluorescent antibodies faces challenges due to background noise from unbound probes.
- Precise visualization of intracellular targets in living cells is crucial for diagnostics and therapeutics.
- p53, a key tumor suppressor, is a validated biomarker for cancer, but its live-cell imaging is complex.
Purpose of the Study:
- To develop a novel probe for spatiotemporally visualizing intracellular p53 in living cells with reduced background signal.
- To create a conditionally active Quenchbody (Q-body) probe capable of targeting and imaging intracellular proteins.
- To demonstrate the feasibility of Q-body probes for live-cell sorting based on intracellular biomarker expression.
Main Methods:
- Development of a Fab-type Quenchbody (Q-body) probe derived from a monoclonal antibody (DO-1).
- In vitro characterization of Q-body fluorescence enhancement and limit of detection for p53.
- Application of Q-body probes in fixed and live cells for intracellular p53 imaging.
- Demonstration of live-cell sorting utilizing Q-body-based p53 detection.
Main Results:
- The Q-body exhibited up to 27-fold p53 level-dependent fluorescence enhancement in vitro, with a limit of detection of 0.72 nM.
- Significant fluorescence enhancement (8.3-fold in fixed cells, 8.4-fold in live cells) was observed.
- Successful live-cell sorting based on intracellular p53 expression was achieved using the Q-body probe.
Conclusions:
- Q-body probes offer a novel and effective method for low-background, high-sensitivity imaging of intracellular biomarkers like p53 in living cells.
- This technology enables precise live-cell visualization and functional applications such as cell sorting.
- The study establishes the feasibility and broad applicability of Q-body probes for intracellular target-based research and diagnostics.
