Mon, Feb. 27, 2017, 4:30pm
Princeton Neuroscience Institute, Lecture Hall A32
Host: Tom Muir
DNA BASES BEYOND WATSON AND CRICK
Epigenetic information is stored in the form of modified bases in the genome. The positions and the kind of the base modifications determines the identity of the corresponding cell. Setting and erasing of epigenetic imprints controls the complete development process starting from an omnipotent stem cells and ending with an adult specialized cell. I am going to discuss the latest results related to the function and distribution of the epigenetic marker bases 5-hydroxymethylcytosine (hmC), 5-formylcytosine (fC), 5-carboxycytosine (caC) and 5-hydroxymethyluracil (Scheme 1). These nucleobases control epigenetic programming of stem cells and some of these bases are also detected at relatively high levels in brain tissues. Synthetic routes to these new bases will be discussed that enable today preparation of oligonucleotides containing the new bases. The second part of the lecture will cover mass spectroscopic approaches to decipher the biological functions of the new epigenetic bases of which some were described in the past as pure DNA lesions. In particular, results from quantitative mass spectrometry, new covalent-capture proteomics mass spectrometry and isotope tracing techniques will be reported. The data allow us to unravel the chemistry in stem cells and the protein networks that are controlled by the epigenetic base modifications. Finally I am discussing potential präbiotic origins of these modfied bases.
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A high-yielding, strictly regioselective prebiotic purine nucleoside formation pathway.