How do you check for DNA damage?
DNA damage can be measured as an indicator of genotoxicity using an antibody against phosphorylated H2AX. By combining specific antibody-based detection of DNA damage with a cytotoxicity indicator, both parameters can be measured simultaneously in the same cell.
How does DNA damage lead to apoptosis?
Apoptosis induced by many chemical genotoxins is the consequence of blockage of DNA replication, which leads to collapse of replication forks and DSB formation. These DSBs are thought to be crucial downstream apoptosis-triggering lesions.
What is the relationship between DNA damage mutation and cell death?
DNA damage can affect normal cell replicative function and impact rates of apoptosis (programmed cell death, often referred to as ‘cellular senescence’). Alternatively, damage to genetic material can result in impaired cellular function, cell loss, or the transformation of healthy cells to cancers.
What causes apoptosis?
Apoptosis is mediated by proteolytic enzymes called caspases, which trigger cell death by cleaving specific proteins in the cytoplasm and nucleus. Caspases exist in all cells as inactive precursors, or procaspases, which are usually activated by cleavage by other caspases, producing a proteolytic caspase cascade.
What is p53 in apoptosis?
Tumor protein p53 is a nuclear transcription factor that regulates the expression of a wide variety of genes involved in apoptosis, growth arrest, or senescence in response to genotoxic or cellular stress.
Where does p53 stop the cell cycle?
In normal cells, the p53 protein level is low. DNA damage and other stress signals may trigger the increase of p53 proteins, which have three major functions: growth arrest, DNA repair and apoptosis (cell death). The growth arrest stops the progression of cell cycle, preventing replication of damaged DNA.
How is p53 activated?
The tumour suppressor protein p53 is stabilised and activated in response to ionising radiation. This is known to depend on the kinase ATM; recent results suggest ATM acts via the downstream kinase Chk2/hCds1, which stabilises p53 at least in part by direct phosphorylation of residue serine 20.