Direct Methylation Sequencing via Polymerase Kinetics
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Solution Overview
Problem
Current methylation profiling techniques, such as bisulfite sequencing and methylated DNA immunoprecipitation, face limitations including high sample preparation time, DNA degradation, and reduced resolution, especially in repetitive genomic regions, making them unsuitable for de novo methylation profiling and genome-wide analysis.
Innovation Solution
A direct methylation sequencing technology that monitors the kinetics of single polymerase molecules in real-time, allowing for fast and economical analysis of methylation patterns, even in repetitive regions, by detecting changes in enzyme activity indicative of methylated bases during nucleic acid synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bisulfite sequencing is used for methylation profiling, then single-nucleotide resolution can be achieved, but sample preparation time increases significantly and DNA degradation occurs
Solution Approach 1:
The method performs methylation detection during the sequencing process itself, rather than requiring separate preliminary bisulfite conversion steps. The polymerase directly detects methylated cytosines during DNA synthesis, eliminating the time-consuming pre-treatment while maintaining single-nucleotide resolution
Solution Approach 2:
The invention extracts the methylation detection function from separate pre-processing steps and integrates it directly into the polymerase activity during sequencing. This allows real-time detection of methylated bases without requiring DNA to undergo bisulfite conversion beforehand
2Measurement precision
If bisulfite sequencing is used for methylation profiling, then single-nucleotide resolution can be achieved, but DNA degradation occurs necessitating large starting amounts
Solution Approach 1:
Instead of using harsh bisulfite chemistry that degrades DNA, the method employs a gentle polymerase-based detection system that naturally distinguishes methylated from unmethylated cytosines during DNA synthesis. This converts the harmful chemical treatment approach into a beneficial enzymatic detection approach that preserves DNA integrity
Solution Approach 2:
The invention replaces the mechanical/chemical bisulfite conversion process with an enzymatic polymerase-based detection system. The polymerase enzyme naturally incorporates nucleotides at different rates depending on whether the template cytosine is methylated, providing detection without physical or chemical damage to the DNA
3Productivity
If methylated DNA immunoprecipitation is used, then genome-wide assessment can be performed, but base resolution is reduced
Solution Approach 1:
The method merges the genome-wide assessment capability of immunoprecipitation with the base-resolution precision of sequencing. By performing methylation detection directly during sequencing, the system achieves both high throughput for genome-wide analysis and single-nucleotide precision simultaneously
Solution Approach 2:
The sequencing-based methylation detection method serves multiple functions: it provides genome-wide coverage like immunoprecipitation, achieves base-resolution precision like bisulfite sequencing, and enables de novo methylation profiling without requiring reference genomes or pre-designed probes
4Loss of information
If bisulfite sequencing is used, then methylation patterns can be analyzed, but the harsh reaction conditions lead to DNA degradation
Solution Approach 1:
The method changes the fundamental parameter of detection from chemical conversion (bisulfite) to enzymatic recognition (polymerase kinetics). This parameter change allows methylation analysis under physiological conditions without the harsh chemical treatment that causes DNA degradation
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 provides high-resolution, real-time detection of methylated sites, enhancing the understanding of DNA methylation patterns and overcoming the limitations of existing methods, particularly in repetitive genomic areas.
Implementation Method 1
A change or perturbation in the processing is detected, and this change is indicative of the presence of the modification in the template. In certain embodiments, the change or perturbation in processing is a change in the kinetics of the processing
Data Source
AI summary
A method for identifying a 5-MeC in a template nucleic is provided. The method comprises providing a template having 5-MeC, converting the 5-MeC into a further modification selected from 5-caC and 5-FC. The converted template is then sequenced, and a change in sequencing is detected that is indicative of the further modification, allowing for identifying the 5-MeC in the template nucleic acid.