The mechanism of prevention of "ultraviolet" cancer is revealed
American scientists from the University of North Carolina Medical School have found out how one of the mechanisms for repairing damaged DNA, called excision repair of nucleotides, works. It prevents mutations caused by ultraviolet radiation and the appearance of skin cancer cells. The researchers' article was published in the journal Proceedings of the National Academy of Sciences (Adebali et al., Genome-wide transcription-coupled repair in Escherichia coli is mediated by the Mfd translocase – VM). Briefly about the study is described on the website Phys.org (How life survives: Researchers confirm basic mechanism of DNA repair).
Irradiation of cells with ultraviolet light can lead to the formation of bonds in their DNA between pyrimidine nucleotides adjacent to each other on the same chain – pyrimidine dimers arise. The latter contain either thymine (T) or cytosine (C). In this case, there is a gap between complementary bases, as a result of which errors occur when copying DNA. Because of this, skin cells can turn into malignant, which leads to the development of melanoma.
The researchers used the method of mapping damaged XR-SEQ gene sequences to detect areas with pyrimidine dimers. This helped them to trace how cellular mechanisms eliminate defects in DNA in Escherichia coli (Escherichia coli). The scientists focused on the functions of MFD and UvrD proteins, which were thought to be involved in excision repair.
Biologists have found that DNA repair occurs in ordinary cells, but not mutant bacteria, where the genes encoding MFD are artificially disabled. This confirmed the role of protein in damage repair processes. In addition, it turned out that another compound, UvrD, is involved in cutting out a fragment with pyrimidine dimers and removing it from DNA. Scientists have shown that in the absence of UvrD, damaged areas remain in the genes.
The researchers are planning further studies using XR-SEQ in mammalian cells, including humans, where the mechanism of DNA repair is not so well understood.
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08.02.2017