Search results
Results From The WOW.Com Content Network
A double-strand break repair model refers to the various models of pathways that cells undertake to repair double strand-breaks (DSB). DSB repair is an important cellular process, as the accumulation of unrepaired DSB could lead to chromosomal rearrangements, tumorigenesis or even cell death. [ 1 ]
[48] γH2AX (H2AX phosphorylated on serine 139) can be detected as soon as 20 seconds after irradiation of cells (with DNA double-strand break formation), and half maximum accumulation of γH2AX occurs in one minute. [48] The extent of chromatin with phosphorylated γH2AX is about two million base pairs at the site of a DNA double-strand break.
[70] γH2AX (H2AX phosphorylated on serine 139) can be detected as soon as 20 seconds after irradiation of cells (with DNA double-strand break formation), and half maximum accumulation of γH2AX occurs in one minute. [70] The extent of chromatin with phosphorylated γH2AX is about two million base pairs at the site of a DNA double-strand break.
Non-homologous end joining (NHEJ) is a pathway that repairs double-strand breaks in DNA. It is called "non-homologous" because the break ends are directly ligated without the need for a homologous template, in contrast to homology directed repair (HDR), which requires a homologous sequence to guide repair.
In mammalian females the period of arrest may last for years. During this period of arrest, oocytes are subject to spontaneous DNA damage including double-strand breaks. However, the oocytes can efficiently repair DNA double-strand breaks, allowing the restoration of genetic integrity and the protection of offspring health. [8]
Recombination, in this model, is initiated by a double-strand break (or gap) shown in the DNA molecule (chromatid) at the top of the figure. Other types of DNA damage may also initiate recombination. For instance, an inter-strand cross-link (caused by exposure to a cross-linking agent such as mitomycin C) can be repaired by HRR.
Recognition of the damage leads to removal of a short single-stranded DNA segment that contains the lesion. The undamaged single-stranded DNA remains and DNA polymerase uses it as a template to synthesize a short complementary sequence. Final ligation to complete NER and form a double stranded DNA is carried out by DNA ligase. NER can be ...
When mismatches occur in heteroduplex DNA, the sequence of one strand can be repaired to bind the other strand with perfect complementarity. During mitosis, the major homologous recombination pathway for repairing DNA double-strand breaks appears to be the SDSA pathway (rather than the DSBR pathway). [1]