6mA-Seq Method for Bacterial DNA Methylation Detection

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Solution Overview

Problem

Current methods for detecting global 6mA patterns in genomic DNA are costly and not commercially available, limiting the understanding of its role in eukaryotic genomic function and epigenetic regulation, particularly in bacteria where it plays a regulatory role.

Innovation Solution

A novel method, '6mA-Seq', using Illumina sequencing to identify 6mA residues by analyzing genomic DNA libraries with methylation-sensitive restriction enzymes, allowing for the detection of methylated nucleic acid residues through Next Generation Sequencing, enabling the assessment of global methylation patterns in bacterial genomes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If common next generation sequencing (NGS) techniques are used, then sequencing capability is available, but detection of 6mA is not possible

Engineering Contradiction:
Improvedetection capabilityVSAvoid6mA detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary chemical modification step where 6mA residues are converted to a detectable form through treatment with dimethyl sulfate (DS) or iodomethyl sulfate (IMS). This intermediary step enables standard NGS technologies to detect 6mA by transforming the undetectable methylated adenine into a form that causes observable sequencing stops or modifications, thereby bridging the gap between available NGS infrastructure and 6mA detection capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The method changes the chemical state of the 6mA residue through alkylation reactions with DS or IMS, converting the methyl group at the N6 position into a larger alkyl group that interferes with DNA polymerase extension. This parameter change in the chemical structure of the modified base allows standard sequencing technologies to indirectly detect the presence of original 6mA sites through characteristic sequencing artifacts

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If methylation profiling is performed in bacteria, then epigenetic analysis is possible, but current methods are costly and not commercially available

Engineering Contradiction:
Improvemethylation profiling capabilityVSAvoidmethod availability and cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent creates a universal methodology that can detect multiple types of DNA methylation (6mA, 4mC, 5mC) using a single platform approach. By employing chemical treatments that produce characteristic patterns in standard NGS data, the method makes bacterial methylation profiling accessible through existing commercial sequencing services, eliminating the need for specialized expensive equipment or proprietary systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The method uses computational analysis to identify patterns in sequencing data that copy the signature of methylated sites. By analyzing characteristic stops or modifications in the sequencing reads and mapping them back to the reference genome, the system creates a digital copy of the methylation pattern that can be analyzed without requiring physical isolation or specialized detection equipment

Inventive Principle:
Principle #26Copying

3Loss of information

If global 6mA patterns are analyzed, then epigenetic regulation understanding is improved, but detection sensitivity is insufficient with current methods

Engineering Contradiction:
Improveepigenetic information recoveryVSAvoid6mA detection sensitivity
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent applies preliminary chemical treatment to the DNA sample before sequencing to enhance the detectability of 6mA residues. By pre-treating the DNA with dimethyl sulfate or iodomethyl sulfate to alkylate the 6mA sites, the method ensures that when the DNA is subsequently sequenced, the modified sites produce characteristic signals that are easily identifiable, thereby improving detection sensitivity before the actual sequencing measurement occurs

Inventive Principle:
Principle #10Preliminary action

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

Enables rapid and cost-effective analysis of 6mA in genomic DNA, monitoring changes over time and in response to environmental factors, providing insights into its regulatory role in gene expression and disease states.

Implementation Method 1

contacting the library of genomic DNA with a methylation-sensitive restriction enzyme that cleaves the target nucleic acid recognition site only when the target nucleic acid recognition site is unmethylated

Methodology Applied
Scientific EffectRestriction enzyme cleavage: Enzyme

Implementation Method 2

analyzing the digested genomic nucleic acid molecules using next generation sequencing to determine the methylation state of the target nucleic acid recognition sites

Methodology Applied
Scientific EffectNext generation sequencing:

Data Source

PatentEP4010473B1Compositions and methods for detecting methylated DNA
Publication Date: 2024.11.20 BATTELLE MEMORIAL INST
  • EP4010473B1 patent drawingFigure 1
  • EP4010473B1 patent drawingFigure 1
  • EP4010473B1 patent drawingFigure 2

AI summary

Novel methods and compositions are provided for determining global methylation patterns in isolated genomic DNA. The method ustilizes methylation sensitive restriction enzymatic cleavage followed by Next Gernation Sequencing of the remaining DNA to identify sequences comprising methylated nucleic acid residues. In accordance with one embodiment a method is provided for monitoring global methylation patterns in genomic DNAs recovered from organisms or cell populations.