Bimolecular Beacon Segmentation for Accurate Cellular RNA Detection
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Solution Overview
Problem
Conventional molecular beacons are rapidly sequestered into the nucleus of living cells, leading to false-positive signals, sensitivity loss, and inability to accurately measure gene expression due to cell-to-cell variability and inefficient delivery.
Innovation Solution
A bimolecular beacon composition comprising two nucleic acid molecules, where one is linked to a detectable label and the other to a quencher, allowing for ratiometric fluorescence measurements that account for cell-to-cell variability and enhance nuclear export.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional molecular beacons are introduced into living cells, then they can detect target nucleic acids, but they are rapidly sequestered into the nucleus and produce false-positive signals
Solution Approach 1:
The molecular beacon is divided into two separate oligonucleotide molecules: a first oligonucleotide with a fluorophore and a second oligonucleotide with a quencher. This segmentation prevents the beacon from forming a stable stem-loop structure that would be sequestered in the nucleus, while still enabling detection through hybridization-dependent fluorescence changes.
Solution Approach 2:
The invention uses an intermediary mechanism where the two oligonucleotides interact through hybridization to the target sequence, bringing the fluorophore and quencher into proximity only when the target is present. This intermediary approach avoids direct nuclear sequestration while maintaining detection capability.
2Measurement precision
If conventional molecular beacons are used, then they provide fluorescence signal upon hybridization, but they suffer from cell-to-cell variability and heterogeneous delivery that limit accurate measurement of gene expression
Solution Approach 1:
By segmenting the beacon into two separate oligonucleotides that can independently penetrate cells, the invention reduces heterogeneous delivery issues. The separate molecules can more uniformly distribute across cell populations while maintaining their detection function through target-dependent interaction.
3Measurement precision
If conventional molecular beacons are introduced into living cells, then they can hybridize to target RNA, but they are rapidly sequestered into the nucleus and cannot be exported
Solution Approach 1:
The segmented structure of two separate oligonucleotides allows each molecule to independently navigate cellular compartments. This segmentation enables cytoplasmic retention of the beacon components while maintaining their ability to detect target RNA, avoiding nuclear sequestration that plagues conventional single-molecule beacons.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The bimolecular beacon enables accurate gene expression analysis by reducing false signals, improving sensitivity, and allowing reliable monitoring of gene expression and transfection efficiency in individual cells.
Implementation Method 1
One arm of the stem is labeled with a fluorescent dye (fluorophore), whereas the other one is coupled to a quenching molecule. In the stem-loop state the probe does not produce fluorescence because the energy of the fluorophore is transferred to the quenching molecule.
Implementation Method 2
the energy of the fluorophore is transferred to the quenching molecule
Data Source
AI summary
The invention provides novel compositions and methods for the detection of a target molecule. Specifically, the invention provides a bimolecular beacon composition comprising two nucleic acid molecules, and methods thereof. One of the nucleic acid molecule is operably linked to a reporter detectable label and the other nucleic acid molecule is operably linked to a reference detectable label and a quencher. In some embodiments, at least one of the nucleic acid molecules comprises a single stranded overhang.