DNA repair mechanisms

The topic of DNA repair mechanisms will be explored through the sources and types of DNA damage our cells face daily, the major DNA repair pathways, including base excision repair, nucleotide excision repair, and mismatch repair, and the critical roles of DNA polymerases and ligases in these mechanisms. We will explore how defects in these repair systems contribute to cancer, aging, and degenerative diseases. Finally, we'll discuss how understanding DNA repair has led to new strategies for disease prevention and treatment. Every day, the DNA in our cells faces constant assaults from normal metabolic processes and environmental factors, such as ultraviolet light, radiation, and chemicals. These assaults cause DNA damages, like altered bases, cross links, mismatches, and strand breaks. Unrepaired DNA damage can disrupt vital processes like replication and transcription leading to mutations. Accumulated mutations threaten health contributing to cancer and aging. To counteract these threats, cells have evolved DNA repair mechanisms to preserve genome integrity. But to cope with DNA damage, cells use specialized repair pathways. Two main types are base excision repair, BER, and nucleotide excision repair NER. BER targets small non helix distorting lesions with DNA glycosylase initiating by excising the damaged base, followed by endonucleases, polymerase, and ligase, restoring the DNA.