What triggers homologous recombination repair?

What triggers homologous recombination repair?

Evidence suggests that DNA double-strand breaks commonly trigger repair by homologous recombination; these breaks may be caused by the interaction of DNA with chemical radicals, produced as a consequence of cellular metabolism, or by external damaging agents such as ionizing radiations.

How do you fix a double-strand break?

Double-strand DNA breaks are common events in eukaryotic cells, and there are two major pathways for repairing them: homologous recombination and nonhomologous DNA end joining (NHEJ).

What is photoreactivation repair?

Photoreactivation is a type of DNA repair mechanism present in prokaryotes, archaea and in many eukaryotes. It is the recovery of ultraviolet irradiated damages of DNA by visible light. In this DNA repair method cells recovers its DNA after UV exposure induced damages.

How are Holliday junctions resolved?

Cleavage, or resolution, of the Holliday junction can occur in two ways. Cleavage of the original set of strands leads to two molecules that may show gene conversion but not chromosomal crossover, while cleavage of the other set of two strands causes the resulting recombinant molecules to show crossover.

What happens if homologous recombination fails?

Without proper homologous recombination, chromosomes often incorrectly align for the first phase of cell division in meiosis. This causes chromosomes to fail to properly segregate in a process called nondisjunction. In turn, nondisjunction can cause sperm and ova to have too few or too many chromosomes.

What happens if a double-strand break is not repaired?

Double-strand breaks in DNA can be lethal to a cell. And, if not repaired correctly, DSBs can cause deletions, translocations, and fusions in the DNA. These consequences are collectively referred to as genomic rearrangements, and they are commonly found in cancerous cells (Figure 1) (Aplan 2006).

What is error prone repair?

a system that repairs severely damaged bases in DNA by base excision and replacement, even if there is no template to guide base selection. This process is a last resort for repair and is often the cause of mutations. Synonym(s): error-prone repair.