What enzymes provide DNA reparation?
Apurinic/apyrimidinic (AP) endonuclease 2 (Apex2) is well-known as an essential DNA repair enzyme that plays a critical role in DNA repair against the oxidative damage in a variety of cells. It has been reported that AP sites occur in DNA molecules by spontaneous hydrolysis, DNA-damaging agents or by DNA glycosylases.
Which enzyme synthesizes the DNA of both the leading and lagging strand?
Polymerase δ
Polymerase δ can then synthesize both the leading and lagging strands, acting to extend the RNA-DNA primers initially synthesized by the polymerase α-primase complex.
Which of the following agents causes double-strand breaks in DNA?
These causes include reactive oxygen species from oxidative metabolism, ionizing radiation, and inadvertent action of nuclear enzymes (14). Reactive oxygen species (ROS) are a second major cause of DSBs (Fig.
Can DNA polymerase repair DNA?
DNA polymerase alpha is required for semi-conservative replication of DNA but not for repair of DNA. A more recently discovered enzyme, DNA polymerase zeta, appears to be involved in the bypass of damage, without excision, and occurs during DNA replication of a damaged template.
Does p53 act as a DNA polymerase?
p53 functions in DNA repair. p53 under both normal and stress conditions, can help cellular and viral DNA polymerases to promote the repair of DNA in various cellular compartments. The result of p53 activation depends on many variables, including the extent of the stress or damage.
What is the role of p53 in DNA replication?
The experiments revealed that p53 plays an important role during DNA replication. When p53 is ‘healthy’, it binds to the replication fork. This ensures that replication restarts properly after it has passed faulty patches of the DNA. The p53 protein also helps to organize the proteins involved in DNA replication.
Which polymerase does the lagging strand?
Pol α initiates DNA synthesis on both the leading and lagging strands by synthesizing a RNA/DNA hybrid primer. The replicative DNA polymerases, Pol δ and Pol ε, then extend the DNA synthesis from the primer.
What causes double strand break?
The DNA double-strand break (DSB) is the principle cytotoxic lesion for ionizing radiation and radio-mimetic chemicals but can also be caused by mechanical stress on chromosomes or when a replicative DNA polymerase encounters a DNA single-strand break or other type of DNA lesion.
Which polymerase is responsible for DNA repair?
Nucleotide excision-repair uses DNA polymerases delta or epsilon to resynthesize the bases removed during repair of pyrimidine dimers and other bulky adducts in DNA.
What does polymerase delta do?
DNA polymerase δ (Pol δ) occupies a central role in all of these processes: catalyzing the accurate replication of a majority of the genome, participating in several DNA repair synthetic pathways, and contributing structurally to the accurate bypass of problematic lesions during translesion synthesis.