Chapter 13 Flashcards
A method for repairing double-strand breaks that creates two Holliday intermediates, which must be cleaved by resolvases. The genes flanking the repair site may be unchanged or may undergo a reciprocal exchange, depending on how the crossovers are resolved.
double-strand break repair (DSBR)
Recombination between two DNA molecules of similar sequence, occurring in all cells; takes place during meiosis and mitosis in eukaryotes and during the repair of double-strand breaks in all organisms.
homologous recombination
Recombinational processes directed at the repair of DNA strand breaks or cross-links, especially at inactivated replication forks.
recombinational DNA repair
A break in the phosphodiester backbone of both strands of a double-stranded nucleic acid.
double-strand break (DSB)
An enzyme that catalyzes genetic recombination by the reciprocal exchange of short pieces of DNA between longer DNA molecules.
recombinase
The 5’ end is
degraded to produce 3’ single-stranded
extensions
processing of broken ends during recombination to repair DSBs
The pairing of a single-stranded extension of a DNA molecule with a homologous region of another DNA molecule, with displacement of one strand of the recipient molecule by the invading strand
DNA strand invasion
This procedure is made
possible by the pairing formed after the 3’
overhang invaded the homologous strand.
A DNA polymerase is responsible for this step
replicative extension
A pathway for repairing double-strand breaks that ends with the invading strands dissociating and reannealing and with the homologous DNA molecule intact. See also double-strand break repair.
synthesis-dependent strand annealing (SDSA)
An intermediate in genetic recombination in which two double-stranded DNA molecules are joined by a reciprocal crossover involving one strand of each molecule to form a junction with four DNA branches
Holliday intermediate
A nuclease that specifically binds to and cleaves Holliday intermediates
Holliday junction resolvase
Any redistribution of genes between two homologous chromosomes that results from a chromosomal crossover
genetic crossover
Movement of the branch point in a branched DNA formed from two DNA molecules with identical sequences. See also Holliday intermediate
branch migration
A process for repairing gaps left when the replication fork bypasses a lesion
gap repair
A bacterial protein complex that prepares DNA at a double-strand break for repair. The complex has helicase activity to unwind the DNA, an endonuclease activity that creates 3′ single-stranded overhangs, and an activity that loads RecA protein on the 3′-ending single strand.
RecBCD