Effect of chromosome size on aberration levels caused by gamma radiation as detected by fluorescence in situ hybridization.
Effect of chromosome size on aberration levels caused by gamma radiation as detected by fluorescence in situ hybridization.
复制标题
通过荧光原位杂交检测到染色体大小对伽马辐射引起的畸变水平的影响。
DOI：
10.1159/000133807
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Hittelman,WN
中科院分区：
文献类型：
--
作者：
Pandita,TK;Gregoire,V;Dhingra,K;Hittelman,WN
荧光原位杂交(FISH)是一种在染色体水平上检测基因组变化的强有力的技术。为了研究染色体大小对染色体畸变形成的影响，我们用FISH技术检测了γ照射的G₀人细胞个体早熟凝聚染色体的初始损伤。使用1号染色体特异的探针获得了断裂的线性剂量响应和交换的非线性剂量响应。FISH从Giemsa染色的PCC制备的DNA推断中检测到比预期更多的1号染色体断裂。这两种技术检测到的断裂数量的差异引发了这样的问题：吉姆萨染色和FISH在检测断裂方面的敏感性是不同的，还是1号染色体对γ辐射唯一敏感。为了解决技术敏感性的问题，我们使用全基因组涂抹探针来检测FISH的总染色体损伤；Giemsa染色和FISH得到的结果几乎相同。为了确定1号染色体是否是唯一敏感的，我们选择了四个不同大小的染色体作为PAINT探针，并对它们进行了γ-射线诱发的畸变评分。在这些研究中，每单位DNA的染色体断裂数量随着染色体DNA含量的增加而线性增加。然而，每单位DNA的交换次数并没有随着染色体大小的增加而增加。这表明染色体大小可能会影响观察到的畸变率。从单个染色体对整个基因组的损伤的测量推断需要考虑所测量的染色体的相对DNA含量。
Fluorescence in situ hybridization (FISH) is a powerful technique for detecting genomic alterations at the chromosome level. To study the effect of chromosome size on aberration formation, we used FISH to detect initial damage in individual prematurely condensed chromosomes (PCC) of γ-irradiated G₀ human cells. A linear dose response for breaks and a nonlinear dose response for exchanges was obtained using a chromosome 1-specific probe. FISH detected more chromosome 1 breaks than expected from DNA based extrapolation of Giemsa stained PCC preparations. The discrepancy in the number of breaks detected by the two techniques raised questions as to whether Giemsa staining and FISH differ in their sensitivities for detecting breaks, or is chromosome 1 uniquely sensitive to γ-radiation. To address the question of technique sensitivity, we determined total chromosome damage by FISH using a total genomic painting probe; the results obtained from Giemsa-staining and FISH were nearly identical. To determine if chromosome 1 was uniquely sensitive, we selected four different sized chromosomes for paint probes and scored them for γ-ray induced aberrations. In these studies the number of chromosome breaks per unit DNA increased linearly with an increase in the DNA content of the chromosomes. However, the number of exchanges per unit of DNA did not increase with an increase in chromosome size. This suggests that chromosome size may influence the levels of aberrations observed. Extrapolation from measurements of a single chromosome’s damage to the whole genome requires that the relative DNA content of the measured chromosome be considered.