Identification of radiation-sensitive mutants in the Medaka, Oryzias latipes
Identification of radiation-sensitive mutants in the Medaka, Oryzias latipes
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DOI：
10.1016/j.mod.2004.04.002
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发表时间：
2004-07-01
影响因子：
2.6
通讯作者：
Furutani-Seiki, M
中科院分区：
文献类型：
--
作者：
Aizawa, K;Mitani, H;Furutani-Seiki, M
我们筛选了 N-乙基-N-亚硝基脲 (ENU) 诱变的青鳉 (Oryzias latipes) 群体中的辐射敏感突变体，以研究发育胚胎中电离辐射诱导的基因组稳定性机制。来自男性创始人的 F3 胚胎是纯合的，可诱导突变，在器官发生阶段（48 hpf）用伽马射线照射，剂量不会导致野生型胚胎畸形。我们筛选了 2130 个 F2 对，并鉴定了三种类型的突变体，这些突变体在低剂量辐射下具有高发生率的辐射诱发的卷尾 (ric) 畸形。来自这些突变体之一的纯合菌株 ric1 具有高繁殖力且易于繁殖，已建立并表征与伽马辐射响应相关。在桑椹胚和早期原肠胚阶段接受伽马射线照射后，与野生型CAB菌株相比，ric1菌株还表现出更高的畸形发生率和更低的孵化率。我们发现，伽马射线照射后孵化成功率的下降取决于 ric1 基因座的母体基因型。末端脱氧核苷酸转移酶介导的脱氧UTP缺口末端标记测定显示，在早期原肠胚阶段伽马射线照射后，ric1胚胎中立即出现高频率的凋亡，但在中囊胚转变（MBT）之前没有观察到凋亡细胞。中性彗星实验显示，ric1突变体在快速修复伽马射线引起的DNA双链断裂方面存在缺陷。这些结果表明RIC1参与胚胎从桑椹胚到器官发生阶段的DNA双链断裂修复，并且ric1中未修复的DNA双链断裂在MBT后触发细胞凋亡。这些结果支持使用 ric1 菌株来研究体内 DNA 双链断裂的各种生物学后果，并用于敏感监测与低剂量辐射相关的遗传毒性。 (C) 2004 Elsevier Ireland Ltd. 保留所有权利。
We screened populations of N-ethyl-N-nitrosourea (ENU)-mutagenized Medaka, (Oryzias latipes) for radiation-sensitive mutants to investigate the mechanism of genome stability induced by ionizing radiation in developing embryos. F3 embryos derived from male founders that were homozygous for induced the mutations were irradiated with gamma-rays at the organogenesis stage (48 hpf) at a dose that did not cause malformation in wild-type embryos. We screened 2130 F2 pairs and identified three types of mutants with high incidence of radiation-induced curly tailed (ric) malformations using a low dose of irradiation. The homozygous strain from one of these mutants, ric1, which is highly fertile and easy to breed, was established and characterized related to gamma-irradiation response. The ric1 strain also showed higher incidence of malformation and lower hatchability compared to the wild-type CAB strain after gamma-irradiation at the morula and pre-early Gastrula stages. We found that the decrease in hatching success after gamma-irradiation, depends on the maternal genotype at the ric1 locus. Terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end-labeling assays showed a high frequency of apoptosis in the ric1 embryos immediately after gamma-irradiation at the pre-early gastrula stage but apoptotic cells were not observed before midblastula transition (MBT). The neutral comet assay revealed that the ric1 mutant has a defect in the rapid repair of DNA double-strand breaks induced by gamma-rays. These results suggest that RIC1 is involved in the DNA double strand break repair in embryos from morula to organogenesis stages, and unrepaired DNA double strand breaks in ric1 trigger apoptosis after MBT. These results support the use of the ric1 strain for investigating various biological consequences of DNA double strand breaks in vivo and for sensitive monitoring of genotoxicity related to low dose radiation. (C) 2004 Elsevier Ireland Ltd. All rights reserved.