double-strand break repair involved in meiotic recombination

Definition

Target type: biologicalprocess

The repair of double-strand breaks in DNA via homologous and nonhomologous mechanisms to reform a continuous DNA helix that contributes to reciprocal meiotic recombination. [GOC:mah, PMID:15238514]

Double-strand break repair (DSBR) is a critical process in meiotic recombination, ensuring the exchange of genetic material between homologous chromosomes. It involves a complex series of steps, starting with the introduction of a double-strand break (DSB) in the DNA molecule. The DSB is then processed by a series of enzymes, including the MRN complex (MRE11, RAD50, NBS1) and the exonuclease CtIP, generating 3' single-stranded DNA tails. These tails are then bound by the recombinase protein RAD51, forming a nucleoprotein filament that searches for homologous sequences on the sister chromatid or the homologous chromosome. Once a homology is found, the RAD51 filament facilitates strand invasion, displacing the corresponding strand on the homologous chromosome. This leads to the formation of a D-loop structure, where the invading strand is paired with the homologous sequence. The invading strand is then extended by DNA polymerase, using the homologous chromosome as a template. This process generates a Holliday junction, a four-way DNA structure where the two strands are intertwined. The Holliday junction can then be resolved by specialized enzymes, such as the resolvase, resulting in either crossovers or non-crossovers. Crossovers involve the exchange of genetic material between homologous chromosomes, leading to the creation of recombinant chromosomes. Non-crossovers involve the repair of the DSB without exchange of genetic material. The choice between crossover and non-crossover outcomes is influenced by factors such as the location of the DSB, the length of the homologous region, and the specific proteins involved. DSBR in meiotic recombination is essential for proper chromosome segregation, genetic diversity, and fertility. It ensures that each daughter cell receives a complete set of chromosomes with a unique combination of genetic material.'
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Proteins (2)

Compounds (5)