Core genetic information is stored as a specific sequence of the DNA alphabet. The four canonical bases constituting the letters of the DNA alphabet can undergo small changes in their chemical structures to add an additional layer of information on the genome. These modifications allow organisms to use their genome in different ways without altering the core genetic sequence. This is central for living systems to adapt to environmental changes, but also for development and differentiation to different cellular identities. For a better understanding of the development and functioning of organisms and the occurrence of disease, understanding the biological roles of these DNA modifications is fundamental.
One of these modified DNA bases is N6-methyladenine (N6MeA), which is present at high levels in bacterial genomes and at considerably lower levels in the DNA of eukaryotes. Recent studies have suggested that it is also present in vertebrates, including humans, and that its levels changed upon stress exposure, as well as in tumour cells and tissues. Many difficulties in accurately detecting this rare modified DNA base in mammals have however made its study tedious, and in order to further understand the biological importance of N6MeA, more straightforward detection methods are needed.
The goal of this project was to develop a highly selective chemical reaction to modify N6MeA in DNA strands, to be used as basis for deploying novel reliable detection and mapping techniques. In a collaborative effort with the group of Prof. Matthew Gaunt here at the University of Cambridge, we have developed a new chemical reaction to selectively functionalise N6MeA in DNA strands and showed that this can be used for enriching DNA containing this modified base. We expect that this chemistry will have a considerable impact in the field, as has been the case for several other chemistry-based methods to manipulate modified DNA bases. We are currently expanding our efforts to apply this chemistry in different approaches to detect and map N6MeA.
