DNA damage and repair in old and young and in participants in the BLSA

双链断裂是DNA中非常危险的损伤，必须修复才能使细胞完成复制和转录。在双链断裂修复方面有缺陷的细胞容易受到基因组的不稳定，而有这些缺陷的个体患癌症的风险往往更高。双链断裂的存在可以通过检查细胞中一种被称为H_2AX的组蛋白变体的磷酸化形式来确定。蛋白质的磷酸化在双链断裂附近迅速发生，并持续到断裂被修复。因此，磷酸-H_2AX可作为骨折的替代标志物。免疫荧光技术可以很容易地检测到这种物种，因此可以在单细胞中检测到。我们正在通过测定BLSA计划中献血者血液来源细胞中磷酸化H_2AX的水平来检验这一假设，即与年轻个体相比，老年个体的细胞中双链断裂的水平较高。我们还通过凝胶电泳法在单细胞水平上测量dna修复。

Double strand breaks are very dangerous lesions in DNA and must be repaired to allow cells to complete replication and transcription. Cells with deficiencies in double strand break repair are subject to genomic instability and individuals with these deficiencies are often at elevated risk of cancer. The presence of double strand breaks can be determined by examining cells for the phosphorylated form of a histone protein variant known as H2AX. Phosphorylation of the protein occurs rapidly in the vicinity of a double strand break, and persists until the break is repaired. Consequently phospho-H2AX serves a surrogate marker for breaks. This species can be easily detected by immunofluorescence techniques, and thus can be detected in single cells. We are testing the hypothesis that double strand breaks are presented in elevated levels in cells from aged individuals, as compared with younger individuals, by determining the level of phospho-H2AX in blood derived cells from donors in the BLSA program. We are also measuring DNA repair at the single cell level by gel electrophoresis assays