Details of DNA damaged by smoking under research

15 Jan 2015

Researchers have succeeded in copying genes which have been altered by activities such as smoking, which can lead to lung cancer. These copies retain the altered information, helping their efforts to study the damage in detail.

Cancer’s genetic mutation of uncontrolled growing involves chemical changes to individual building blocks of DNA. These changes are induced by smoking tobacco and consuming foods such as cured meats.

A process for studying genes and their changes is called "amplification", and involves making copies to help their analysis. For the first time, researchers from a team led by Shana Sturla, professor of Food and Nutrition Toxicology, have succeeded in amplifying gene samples containing altered forms of DNA (called "adducts") while retaining references to these adducts.

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The scientific method

The researchers focused their efforts on a specific, typical DNA adduct, an alkylguanine called O-6-benzylguanine.  They recreated an enzyme reaction in a test tube, analogous to how DNA is replicated naturally in cells, to obtain a negative copy of the genetic material. As nature produces molecular counterparts to the basic DNA building blocks, but not to DNA adducts, the scientists first had to find an artificial counterpart of the alkylguanine to be incorporated into the negative copy in its position. This is why replicating genes usually leads to copy errors (or mutations) when adducts are present. Researchers produced several artificial derivatives of the basic DNA building blocks in the laboratory and tested them as potential counterparts to the alkylguanine. This method lead them to successfully producing a negative copy of a gene containing the alkylguanine.

An important tool in researching how cancer starts

According to the study author: "the scientific community will have an important tool for making a detailed analysis of the molecular mechanisms involved in the initiation of cancer and the corresponding risk factors." The aim of the work carried out by Sturla and her colleagues, was to demonstrate that it is feasible to amplify genes even when adducts are present. It should now be possible for researchers to find artificial counterparts to other adducts using the same method, making possible to amplify genes and ascertain their sequences more easily in the future.

 

Source: Science Daily
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