CYTOPLASMIC INHERITANCE IN NORMAL AND TUMOR CELLS

正常细胞和肿瘤细胞中的细胞质遗传

基本信息

批准号：
3163614
负责人：
MORGAN HARRIS
金额：
$ 15.16万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
1976
资助国家：
美国
起止时间：
1976-05-01 至 1987-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/3163614
关键词：
carcinogenesis cell population study cellular oncology chloramphenicol clone cells cytogenetics drug resistance extrachromosomal DNA gene expression genetic manipulation hybrid cells mitochondria mutagens neoplasm /cancer genetics ouabain pharmacogenetics tissue /cell culture

项目摘要

We will continue our studies on gene expression using the cloned Chinese hamster gene for thymidine kinase, which we have recently isolated as a DNA probe. Restriction enzyme analysis will be used to determine DNA methylation patterns in or near the TK locus for cells with different levels of expression of thymidine kinase. Two problems to be addressed will be: (1)\whether the timegraded acquisition of BUDR resistance which we have described previously in Chinese hamster cells results from gradual methylation of strategic DNA sites, shutting down expression of thymidine kinase, and (2)\whether reexpression of TK in BUDR-resistant cells after exposure to such diverse agents as 5-azacytidine, butyrate, and hypertonic glycine or NaCl is the common result of hypomethylation at these sites. During the past year we have completed our study of proline independence in CHO-K1 Chinese hamster cells, long regarded as a prototype for auxotrophic mutations in mammalian cells. We have shown that treatment by 5-azacytidine induces proline-independent variants in high frequency with coordinate expression of pyrroline-5-carboxylase and ornithine aminotransferase activities. In this system, as in others we have previously studied (thymidine kinase, asparagine synthetase), variation appears to be based on stable changes in gene expression which masquerade as genetic mutations. Although little known up to the present time, such epigenetic variations may play an important role along with genetic changes in transformation and carcinogenesis. (P)

我们将使用克隆的中文继续研究基因表达胸苷激酶的仓鼠基因，我们最近将其分离为DNA 探测。限制酶分析将用于确定DNA 具有不同细胞的TK基因座中或附近的甲基化模式胸苷激酶的表达水平。两个问题要解决将是：（1）\我们是否定期收购BUDR阻力先前在中国仓鼠细胞中描述了逐渐导致的战略性DNA位点的甲基化，关闭胸苷的表达激酶和（2）\是否在BUDR抗性细胞中重新表达了TK 暴露于5-氮杂丁胺，丁酸酯和高渗的不同代理甘氨酸或NaCl是这些位点降压甲基化的常见结果。在过去的一年中，我们完成了对脯氨酸独立的研究 Cho-k1中国仓鼠细胞，长期以来一直被视为可营养性的原型哺乳动物细胞中的突变。我们已经通过 5-氮杂丁胺在高频中诱导脯氨酸与脯氨酸无关的变体吡咯氨酸-5-羧化酶和鸟氨酸的坐标表达氨基转移酶活性。在这个系统中，就像其他人一样先前研究的（胸苷激酶，天冬酰胺合成酶），变异似乎是基于化妆ade的基因表达的稳定变化作为基因突变。虽然直到现在鲜为人知，但表观遗传变异可能与遗传变化一起起重要作用在转化和致癌作用中。（p）