Analytical developments based on mass spectrometry to detect and quantify DNA mutations

Abstract

Epigenetic modifications, as e.g. methylation of histones and DNA, regulate gene expression. However, misregulation of this methylation can lead to very dangerous diseases as cancers, neurological disorders or autoimmune diseases. DNA also undergoes simply changes in the genomic sequence called mutations. They can be classified in advantageous, neutral and lethal processes. Advantageous mutations can contribute to evolutionary changes due to environmental influences. In contrast, lethal damages of the genomic sequence in cellular processes arising from DNA methylation, replication errors, ionizing radiation, or UV-irradiations, frequently result in cancers.
These important concepts necessary for the macromolecular machinery of life are presented in the first part of Chapter 1. They include also the flow of genetic information in a cell, primary, secondary, and tertiary structures of DNA, as well as packaging of DNA in a cell by proteins called histones.
As the rate of DNA mutation and relative binding affinities of small molecules to DNA will be considered in this thesis, the second part of Chapter 1 deals with quantitative determinations. Aspects of calibration, systematic and random errors, limit of detection, limit of quantification, dynamic range, and linearity are discussed. Combination of chromatography with mass spectrometry is often the method of choice used in quantification. Regarding the sample properties, criteria for selecting the most appropriate analytical method are developed, including chromatography, ionization modes, and mass analyzers.