Hur kan joniserande strålning inducera cancer? Paul Wallin

An optimized method for measurement of gamma-H2AX in

γ-H2AX can be detected by immunoblotting and immunostaining using microscopic or flow cytometric detection. Phosphorylation of the Ser-139 residue of the histone variant H2AX, forming γH2AX, is an early cellular response to the induction of DNA double-strand breaks. Detection of this phosphorylation By tagging gamma-H2AX histones with a fluorescent antibody, Dr. Bonner showed that exposing cells to ionizing radiation caused hundreds of H2AX histones near the site of a double-strand break to become phosphorylated within minutes, creating a rapid and highly amplified response akin to a cellular fire alarm. An antibody to gamma-H2AX reveals that this highly amplified process generates nuclear foci. The phosphorylation site is a serine four residues from the C-terminus which has been evolutionarily conserved in organisms from giardia intestinalis to humans. Phosphorylated histone H2AX (gamma-H2AX) forms foci over large chromatin domains surrounding double-stranded DNA breaks (DSB). These foci recruit DSB repair proteins and dissolve during or after repair is completed.

γ-H2AX can be detected by immunoblotting and immunostaining using microscopic or flow cytometric detection. Phosphorylation of histone H2AX on serine 139 (gamma-H2AX, γH2AX) occurs at sites flanking DNA double-strand breaks (DSBs) and can provide a measure of the number of DSBs within a cell. Here we describe a rapid and simple flow-cytometry-based method, optimized to measure gamma-H2AX in non-fixed peripheral blood cells. The phosphorylation of H2AX can be detected by Western blotting or immunofluorescence, revealing the frequency of DSBs. The phosphatidylinositol 3-kinases have been implicated in H2AX phosphorylation, but it is unclear if ATM is the primary H2AX kinase or if other members of the family such as DNA-PK and ATR contribute in a similar manner.

DSBs induce a strong cellular response via phosphorylation of H2AX, Keywords: DNA double-strand break, DSB; phosphorylated H2AX, P-H2AX; 21 apr.

Hur kan joniserande strålning inducera cancer? Paul Wallin

Trouiller et with BSA: γ-H2AX generation. av FL Tarish · 2015 — level of unrepaired DSBs, measured by γ-H2AX foci in cancer tissues. The levels of AR, Ku70, phosphorylated DNA-PKcs and PAR were mätt med γ-H2AX foci. Denna studie visar att behandlings-inducerad γ-H2AX foci i arm 1 med autophosphorylation site clusters facilitates end processing breaks (DSBs) specifically when modified by C-terminal phosphorylation.

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To our knowledge studies of the relationship of gamma-H2AX expression and the clinical outcome of urothelial carcinoma are lacking. In renal epithelium maximum of the gamma-H2AX-positive cells is observed 40 min after IR and then decreases to control values in 23 h. This indicates that there are significant variations between non-proliferating mammalian tissues in the initial H2AX phosphorylation rate as well as in the rate of gamma-H2AX elimination after X-irradiation Because phosphorylation of H2AX at Ser 139 (γ-H2AX) is abundant, fast, and correlates well with each DSB, it is the most sensitive marker that can be used to examine the DNA damage produced and the subsequent repair of the DNA lesion. γ-H2AX can be detected by immunoblotting and immunostaining using microscopic or flow cytometric detection. Phosphorylation of histone H2AX on serine 139 (gamma-H2AX, γH2AX) occurs at sites flanking DNA double-strand breaks (DSBs) and can provide a measure of the number of DSBs within a cell. Here we describe a rapid and simple flow-cytometry-based method, optimized to measure gamma-H2AX in non-fixed peripheral blood cells. The phosphorylation of H2AX can be detected by Western blotting or immunofluorescence, revealing the frequency of DSBs.

Ataxia telangiectasia mutated (ATM) is considered a key protein for H2AX phosphorylation (1-4). 2010-03-06 · DNA DSB induced by gamma irradiation, or other DSB inducers, leads to rapid phosphorylation of H2AX at Ser139 by ATM, ATR and DNA-PKcs, resulting in γH2AX . The foci formed by γH2AX can recruit DNA damage response proteins, such as BRCA1, 53BP1, and MDC1, to initiate DNA repair [ 5 , 27 , 28 ]. Histone H2AX rapidly undergoes phosphorylation at Ser139 (gamma-H2AX) in response to DNA double-strand breaks. Although ATM kinase and DNA-PK phosphorylate Ser139 of H2AX in culture cells, the regulatory mechanism of gamma-H2AX level remains unclear in vivo. Here, we detected the phosphorylation of H2AX and the elimination of gamma-H2AX in the mouse skin after X-irradiation. Furthermore Keywords: Gamma-H2AX, High-content screening, Image processing, Hough transform, dosimetry 1.
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The differences in modification change the function of H2ABbd compared to H2A. As previously mentioned, variant H2AX was found to function in DNA repair. This function is dependent upon the phosphorylation of H2AX C-terminal. Once H2AX becomes phosphorylated, it can function in DNA repair.

While DNA double-strand breaks (DSBs) provide a strong stimulus for this event, the accompanying structural alterations in chromatin may represent the actual signal that elicits gamma-H2AX. Se hela listan på hindawi.com 2009-09-01 · An increase in H2AX phosphorylation, as visualised by γH2AX foci, was found in response to increasing concentrations of etoposide, bleomycin or methyl methanesulfonate (MMS).
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Immunofluorescence Imaging of DNA Damage and Repair

H2AX est phosphorylée au niveau de la sérine 139, appelé alors gamma-H2AX, en réaction aux coupures double-brin de l'ADN. Les kinases de la famille PI3 ( Ataxie télangiectasie mutée , ATR et ADN-PKcs) sont responsables de cette phosphorylation, en particulier ATM. The gamma-H2AX Assay for Genotoxic and Nongenotoxic Agents: Comparisonof H2AX Phosphorylation with Cell Death Response. Teodora Nikolova, Mirek Dvorak, Fabian Jung, Isabell Adam, Elisabeth Krämer, Aslihan Gerhold-Ay, Bernd Kaina Gamma H2AX and its phosphorylation can be detected through western blotting and immunofluorescence, serving as a biomarker for DSB frequency (1-4). Ataxia telangiectasia mutated (ATM) is considered a key protein for H2AX phosphorylation (1-4). 2007-01-23 · Phosphorylated on Ser-140 (to form gamma-H2AX or H2AX139ph) in response to DNA double strand breaks (DSBs) generated by exogenous genotoxic agents and by stalled replication forks, and may also occur during meiotic recombination events and immunoglobulin class switching in lymphocytes. While the suppression of DNA replication aphidicolin prevented the induction of H2AX phosphorylation by UV in most S phase cells, it had no effect on a small cohort of cells that appeared to be entering S-phase, that expressed very high levels of γH2AX. Furthermore, aphidicolin itself induced γH2AX in early-S phase cells.

Immunofluorescence Imaging of DNA Damage and Repair

Gamma‐H2AX is used widely as DNA damage marker in vitro, but its use for genotoxicity assessment in vivo has not been extensively investigated. The phosphorylation of histone H2AX in Serine 139 (gamma‐H2AX) marks regions of DNA double strand breaks and contributes to the recruitment of DNA repair factors to the site of DNA damage. Gamma‐H2AX is used widely as DNA damage marker in vitro , but its use for genotoxicity assessment in vivo has not been extensively investigated. Histone H2A.X (H2AX) is a member of the histone H2A family which is one of the four core histones making up the nucleosome core particle. In eukaryotes, DNA double strand breaks (DSBs) have been shown to trigger the phosphorylation of serine 139 at the carboxy terminus of histone H2AX resulting in gamma-H2AX. Histone H2A.X (H2AX) is a member of the histone H2A family which is one of the four core histones making up the nucleosome core particle.

H2AX (H2A histone family member X) helps to maintain genome stability. It plays an important role in localisation and structuring of the repair focus. H2AX also plays an active role in supplying the active repair proteins. γH2AX participates in DSB repair. This protein serves as a signal and target of phosphorylation in the spreading phase. Medvedeva, N. G., Panyutin, I. V., Panyutin, I. G. and Neumann, R. D. Phosphorylation of Histone H2AX in Radiation-Induced Micronuclei.