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Francisco Javier Novo Villaverde, Professor of Science School

DNA defenses


Thu, 08 Oct 2015 11:05:00 +0000 Published in Navarra Newspaper

When Watson and Crick discovered the famous double helix structure of DNA in 1953, scientists initially believed that this molecule should be stable and resistant; otherwise, it would be difficult to faithfully transmit the information Genetics from one generation to the next. On the other hand, various programs of study studies carried out in the second half of the last century showed that DNA is a relatively fragile molecule and that it is exposed to all kinds subject of aggressions inside and outside the cells. This logically calls for the existence of cellular mechanisms that could repair all these genetic lesions, to prevent them from accumulating over time. The 2015 award Nobel Prize for Chemistry , announced yesterday, recognizes the work of three researchers whose work has been fundamental in elucidating the functioning of these mechanisms for repairing genetic material. Because, at this level of detail, the boundary between biology and Chemistry is blurred, for some even non-existent.

Cells use three main pathways to defend themselves against DNA damage, ranging from small chemical modifications to nucleotides (the letters of the genome) caused by chemical agents such as tobacco smoke, to more drastic and voluminous changes, such as those triggered by ultraviolet radiation from sunlight. Depending on the specific subject damage, the cell will use one mechanism or another to repair its DNA. Sometimes it will change only the damaged part of a nucleotide. Other times, it will remove a larger fragment, consisting of twenty or thirty letters in a row, and fill the gap with normal nucleotides. If the problem is the incorrect pairing of letters that under normal conditions never join together, the cell has at its disposal another specific mechanism that will take care of repairing this subject problem.

If any of these repair mechanisms malfunction, the result usually results in cellular chaos, the most frequent expression of which is the appearance of a tumor lesion or the development of a disease Genetics generally associated with increased predisposition to some subject cancer. A subject colon cancer, for example, is due to the malfunction of one of these three repair pathways. Thus, the research of Lindahl, Modrich and Sancar has shed light on basic processes for the life of cells, which always translates into fundamental advances in the diagnosis and treatment of human diseases. Thanks to them we know in detail the molecular instructions of many types of cancer and important genetic diseases, and this has also translated into new treatments that have benefited millions of people. Think, for example, of the tremendous impact of radiotherapy or some types of chemotherapy, treatments that selectively kill cancer cells because they do not repair their DNA as effectively as healthy cells. It can therefore be said that the work of this year's award-winning researchers has had an extraordinary impact on biomedicine over the last thirty years.