DNAreparaatioita

DNAreparaatioita, known in English as DNA repair, refers to a collection of cellular mechanisms that function to counteract DNA damage. DNA is constantly exposed to various damaging agents, including environmental mutagens like UV radiation and chemicals, as well as endogenous factors like reactive oxygen species. If left unrepaired, this damage can lead to mutations, which can have severe consequences for the cell and the organism, including cancer and premature aging.

There are several major pathways for DNA repair. Nucleotide excision repair (NER) is a versatile mechanism that removes and replaces damaged nucleotides, particularly bulky lesions caused by UV radiation. Base excision repair (BER) targets smaller DNA base modifications, such as oxidized or alkylated bases, by removing the damaged base and then synthesizing a new one. Mismatch repair (MMR) corrects errors that occur during DNA replication, such as mismatched base pairs. Double-strand break repair (DSBR) deals with the most severe type of DNA damage, breaks in both strands of the DNA helix. This can be repaired through homologous recombination (HR), which uses a homologous DNA template, or non-homologous end joining (NHEJ), which directly ligates the broken ends.

These repair systems are crucial for maintaining genomic stability and preventing disease. Defects in DNA repair pathways are associated with a variety of genetic disorders and increased susceptibility to cancer. The study of DNA repair mechanisms has provided significant insights into the fundamental processes of life and has implications for understanding and treating diseases.