Method for the carry-over protection in DNA amplification systems targeting methylation analysis achieved by a modified pre-treatment of nucleic acids

US7700282B2 · kind B2 · utility

Assignee

• EPIGENOMICS AG · DE

Inventors

• Reimo Tetzner · Berlin, DE
• Dimo Dietrich · Berlin, DE

Key dates

• Filing date: Oct 11, 2005
• Grant date: Apr 20, 2010
• Expiry date: Dec 14, 2025

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C12Q2600/156
• WIPO field: Biotechnology
• WIPO sector: Chemistry

Abstract

Particular aspects provide methods for specific amplification of template DNA in the presence of potentially contaminating PCR products from previous amplification experiments. Particular embodiments comprise, in a first step, contacting DNA with a bisulfite solution, which sulfonates unmethylated (but not methylated) cytosines, resulting in cytosine deamination and generation of sulfonated uracil. Such sulfonation protects the template nucleic acid from being a target for the enzyme uracil-DNA-glycosylase (UNG), whereas any contaminating DNA, which contains unprotected unsulfonated or desulfonated uracils, is degraded enzymatically while the UNG is active. After UNG treatment and inactivation thereof, the sulfonated uracil bases are converted into uracil by desulfonation. Such aspects have substantial utility for decontamination of nucleic acid samples; e.g., for avoiding amplification of ‘carry over products’ in the context of DNA methylation analysis. In further aspects, the inventive methods can be generally used as simplified methods of bisulfite treatment.