GENOMIC INSTABILITY AND MOLECULAR MECHANISM OF DELAYED MUTAION IN Fl MICE BORN TO IRRADIATED SPERMATOZOA

受辐射精子所生 Fl 小鼠基因组不稳定性和延迟突变的分子机制

基本信息

批准号：
12480156
负责人：
NIWA Ohtsura
金额：
$ 10.37万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12480156/
关键词：
radiation genomic instability untargeted mutation delayed mutation pink-eyed unstable allele minisatellite genomic crosstalk p53 dependent S checkpoint マウス初期胚 DNA合成抑制色素上皮細胞 pink-eyed unstabel allele p53-遺伝子

项目摘要

Radiation is known to induce genomic instability Which is characterized by the induction of untargeted mutation and delayed mutation. In this investigation, mutation due to genomic instability was tested in F1 mice born to irradiated father. Length change mutation at the maternally inherited allele of the mouse Ms6hm hypervariable minisatellite locus was found to increase in frequencies when born to fathers irradiated at the spermatozoa stage. Similarly, a higher frequency of somatic reversion at the maternally inherited pink-eyed unstable allele was observed in Fl mice born to irradiated spermatozoa. These demonstrated that DNA damage introduced into zygote by irradiated sperm triggers genomic instability in zygotes and in embryos of subsequent developmental stages, resulting in induction of untargeted mutation at the maternal allele of the minisatellite locus, and delayed mutation in retinal pigment epithelial cells in developing eyes.The above study indicates that there exists a genomic crosstalk between damaged paternal genome and undamaged maternal genome. In order to investigate the molecular nature of this genomic crosstalk, we have studied radioresponses in mouse zygotes fertilized by irradiated sperm. A p53 responsive reporter was efficiently activated in female pronucleus. [3H]-Tdr labelingexperiments indicated that sperm irradiated zygotes was devoid of G1/S arrest, but pronuclear DNA synthesis was suppressed equally in male and female pronuclei. P53 -/- zygotes lacked this suppression which was corrected by microinjection of GST-p53 fusion protein. About a half of 6 Gy sperm irradiated zygotes managed to synthesize a full DNA content by prolonging S phase while the other half failed to do so. Regardless of the DNA content, all the zygotes cleaved to become 2 cell stage embryos. These results revealed the presence of p53 dependent pronuclear crosstalk and a novel function of p53 in S phase DNA-damage checkpoint of mouse zygotes.

已知辐射会诱导基因组不稳定性，其特征是诱导未靶向突变和延迟突变。在这项调查中，在受辐照的父亲出生的F1小鼠中测试了由于基因组不稳定性引起的突变。小鼠MS6HM高度变量微型座位基因座的母体遗传等位基因处的长度变化突变被发现在精子阶段受辐照的父亲出生时会增加频率。同样，在辐照精子出生的FL小鼠中观察到在母体遗传的粉红色眼睛不稳定等位基因处的较高的体细胞逆转频率。这些表明，通过辐照精子引起的DNA损伤引发了合子中的基因组不稳定和随后发育阶段的胚胎中的基因组不稳定，从而导致在微型层层的孕产妇等位基因上诱导无靶向的突变，并在上面的眼睛中延迟了在肿瘤上的突变。父亲基因组和未损坏的母体基因组。为了研究该基因组串扰的分子性质，我们研究了在被辐照精子施肥的小鼠合子中进行的辐射剂。 p53响应性记者在女性原核中有效激活。 [3H] -tdr labingExperiments表明，精子受辐照的合子没有G1/s的停滞，但在雄性和雌性prainuclei中均等抑制前核DNA合成。 p53 - / - 合子缺乏这种抑制作用，该抑制是通过对GST-P53融合蛋白的显微注射来纠正的。 6 Gy精子中，大约有一半通过延长S阶段来合成完整的DNA含量，而另一半未能这样做。不管DNA含量如何，所有的Zygotes裂解为2个细胞阶段胚胎。这些结果揭示了p53依赖性前串扰串扰的存在以及p53在小鼠zygotes的S相DNA破坏检查点中的新功能。