Single-Cell Assay for Gene Silencing via Chromosomal Contact Perturbation
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Solution Overview
Problem
Current methods for silencing gene expression, such as siRNA approaches, fail to reveal cell-to-cell variability and have off-target effects, while traditional studies on chromosomal contact and transcriptional activity are obscured due to their population-based nature, lacking the ability to discretely perturb chromosomal contacts in multigene complexes.
Innovation Solution
A single cell assay using TALENs to induce site-specific double-stranded breaks in chromosomal contacts within gene loops, allowing for the discrete perturbation of chromosomal contacts and monitoring the effects on transcriptional activity using RNA FISH and immunofluorescence microscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If siRNA approaches are used to silence gene expression, then gene silencing can be achieved, but cell-to-cell variability cannot be revealed and off-target effects occur
Solution Approach 1:
The invention transitions from population-level analysis to single-cell analysis by segmenting the measurement process. Individual cells are isolated and analyzed separately using microfluidic droplet encapsulation, allowing detection of cell-to-cell variability in gene expression and chromosomal contact status that was previously obscured in bulk population measurements.
Solution Approach 2:
The invention introduces an intermediary approach by using chromosomal contact status as a proxy indicator for transcriptional activity. Instead of directly measuring gene expression in every cell, the patent uses the presence or absence of chromosomal contacts (detected via FISH) as a surrogate marker that correlates with active transcription, enabling inference of gene activity states without direct mRNA measurement in all cells.
2Quantity of substance
If traditional chromosomal contact studies are conducted using population-based methods, then global interactome can be characterized, but single-cell dynamics and heterogeneity are obscured
Solution Approach 1:
The invention divides the population-based chromosomal contact study into single-cell units. By encapsulating individual cells in microfluidic droplets and performing FISH analysis on each cell separately, the method resolves the dynamic heterogeneity of chromosomal contacts at single-cell level while still allowing aggregation of data across populations to reconstruct global interactome patterns.
Solution Approach 2:
The invention captures the dynamic nature of chromosomal contacts by analyzing living or fixed single cells in their native state rather than extracting DNA for static population analysis. This allows observation of transient chromosomal interactions and their correlation with transcriptional bursts in real-time or near-real-time conditions.
3Adaptability or versatility
If site-specific nucleases are used to disrupt chromosomal contacts, then discrete perturbation of gene loops can be achieved, but the complexity of the assay increases
Solution Approach 1:
The invention employs a multi-functional assay platform that combines FISH detection of chromosomal contacts, single-cell isolation via microfluidics, and transcriptional activity measurement in a unified workflow. This universal platform can detect various chromosomal interactions (enhancer-promoter, loop structures) and gene expression states using the same basic methodology, reducing the need for separate specialized assays for each type of chromosomal analysis.
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
This approach enables the precise silencing of gene expression and reveals the hierarchical influence of chromosomal contacts on co-regulated genes, providing insights into the role of loop-mediated contact in transcriptional regulation at a single cell level, overcoming the limitations of previous methods.
Implementation Method 1
TALENs to induce site-specific double-stranded breaks in chromosomal contacts within gene loops
Implementation Method 2
monitoring the effects on transcriptional activity using RNA FISH
Implementation Method 3
immunofluorescence microscopy
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
This invention relates to a single cell assay for determining the effect of chromosomal contact on the transcriptional activity of genes of interest in a cell and to methods of silencing gene expression in a cell by way of perturbing gene regulatory elements which are engaged in chromosomal contact.