Description: Nucleotide excision repair (NER) is an essential DNA repair mechanism that removes damaged segments of DNA, specifically those that exhibit distortions in the double helix. This process is crucial for maintaining genetic integrity, as DNA can suffer damage for various reasons, including exposure to ultraviolet radiation, chemical products, and errors during replication. NER occurs in several stages: first, the damage in the DNA is recognized; then, the affected segment is excised; and finally, a new DNA fragment is synthesized using the complementary strand as a template. This mechanism is highly conserved in eukaryotic and prokaryotic organisms, underscoring its importance in cellular biology. NER is not only vital for DNA repair but also plays a role in regulating gene expression and responding to DNA damage, thus contributing to genomic stability and the prevention of diseases such as cancer.
History: Nucleotide excision repair was first identified in the 1970s when it was discovered that certain organisms could repair DNA damage caused by ultraviolet radiation. Subsequent research, particularly in the context of xeroderma pigmentosum, a genetic disorder that increases sensitivity to sunlight and the risk of skin cancer, led to the identification of the genes responsible for NER. In 1993, the Nobel Prize in Chemistry was awarded to researchers who contributed to the understanding of this mechanism, solidifying its importance in molecular biology.
Uses: Nucleotide excision repair is used in molecular biology studies to investigate cellular responses to DNA damage. It is also relevant in cancer research, as mutations in the genes responsible for NER can contribute to tumor development. Additionally, its application is explored in gene therapies and in the development of drugs that may enhance cells’ ability to repair their DNA.
Examples: An example of the importance of nucleotide excision repair is seen in patients with xeroderma pigmentosum, who have a deficiency in this mechanism and are prone to developing skin cancer after exposure to sunlight. Another case is the use of genetically modified mouse models to study the function of NER genes and their relationship to cancer.
