Where is the checkpoint for DNA damage?
The G2/M checkpoint This checkpoint is operational in late G2 phase and presumably allows for repair of DNA that was damaged in late S or in the G2 phases of cell cycle prior to mitosis. Thus, the G2 checkpoint functions to prevent damaged DNA being segregated into daughter cells.
What happens in DNA damage checkpoint?
The DNA damage checkpoint is a signaling cascade that is initiated by DNA damage and triggers cell cycle arrest to allow enough time for repair to take place.
What is the role of recombination in repairing damaged DNA?
Recombination repair is a mechanism for generating a functional DNA molecule from two damaged molecules. It is an essential repair process for dividing cells because a replication fork may arrive at a damaged site, such as a thymine dimer, before the excision repair system has eliminated damage.
How do you do a comet assay?
Comet assay utilizes single cells to measure DNA damage. First, cells are embedded into agarose and then placed onto a slide. The slide is then immersed into lysis solution to break open the cell membrane. After the cells are lysed, DNA is denatured under neutral or alkaline conditions and run through electrophoresis.
What are the phenotypes of Nijmegen breakage syndrome (NBS)?
The chromosomal instability syndromes Nijmegen breakage syndrome (NBS) and ataxia telangiectasia (AT) share many overlapping phenotypes, including cancer predisposition, radiation sensitivity, cell-cycle checkpoint defects, immunodeficiency, and gonadal dysfunction.
What do nbs1h45amice and nbs1657δ5mice have in common?
We have previously reported that Nbs1H45Amice share many overlapping phenotypes with Nbs1657Δ5mice, including defective thymocyte and oocyte development, genomic instability, and a reduction in phosphorylation of the ATM downstream target Chk2 at low IR doses (7). These phenotypes are similarly observed, but more severe, in ATM knockout mice.
What is nbs1tr735mice?
Nbs1tr735mice produced a truncated protein, as indicated by the fact that antibodies against the Nbs1 C terminus (aa 735–754) (50) failed to detect the protein, whereas the protein was detected using an antibody that recognizes the N terminus (aa 395–743; Fig. 1 B).