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Big News: the 2015 Nobel for DNA Repair *and* Neuronal DNA damage (during gene expression?)!

posted Oct 7, 2015, 7:20 AM by Rachel Aronoff   [ updated Oct 8, 2015, 1:45 PM ]
The announcement of this year's Nobel Prizes has already begun, and DNA Repair is the big winner for the Chemistry Prize!  The Royal Swedish Academy of Sciences awarded three researchers, who “mapped, at a molecular level, how cells repair damaged DNA and safeguard the genetic information” - key processes helping preserve genomic integrity!  The first scientist, Tom Lindahl, was the pioneer in the field and worked in the '70s to define base excision repair; the second, Aziz Sancar, defined nucleotide excision repair, especially important to repair damage from UV and carcinogens; and the third, Paul Modrich, helped explain repair of mismatches that occur in particular when DNA is replicated.  Congratulations to them all, and to the current Nobel committee, which apparently has realized how important these processes must be!  A nice summary can also be found on the website of the journal Nature.  
More big news worth mentioning comes from a recent publication, out last week in the journal Science, from researchers at Harvard, who performed single cell complete genome sequencing on neurons from (post-mortem brain tissue of once) healthy individuals, allowing them to not only identify thousands of single nucleotide variations in the obtained sequence, but begin to trace the developmental lineages of the cells.  In other words, neural cells in the same area of the brain could also carry the same mutations, so these analysis were allowing them to map, in a sense, how certain neurons end up in that particular area.  Another interesting point from the study is that the number of sequence changes found in these mature (no longer dividing, or 'post-mitotic') cortical neurons was similar to that found in other normal cells (about 1500 changes), except skin cells, which can exhibit much higher frequencies because of exposure to UV light.  Not only this, but some mutational changes were within genes already shown to be involved in mental diseases, like schizophrenia, and were believed to arise during gene expression (transcription)!  More information about this study is briefly summarised here.  Although the number of cells sequenced was low, with just 36 total neurons analysed from 3 individuals, such studies highlight the potential for understanding how changes in neuronal DNA might contribute to disease.