The dihydrofolate reductase amplicons in different methotrexate-resistant Chinese hamster cell lines share at least a 273-kilobase core sequence, but the amplicons in some cell lines are much larger and are remarkably uniform in structure
The dihydrofolate reductase amplicons in different methotrexate-resistant Chinese hamster cell lines share at least a 273-kilobase core sequence, but the amplicons in some cell lines are much larger and are remarkably uniform in structure
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不同甲氨蝶呤抗性中国仓鼠细胞系中的二氢叶酸还原酶扩增子共享至少273kb的核心序列，但某些细胞系中的扩增子要大得多，并且结构非常均匀
DOI：
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发表时间：
1988
影响因子：
5.3
通讯作者：
J. Hamlin
中科院分区：
文献类型：
--
作者：
J. Looney;C. Ma;T. Leu;W. Flintoff;W. B. Troutman;J. Hamlin
我们之前已经从抗甲氨蝶呤的中国仓鼠卵巢细胞系(CHEC 400)中克隆并鉴定了两种不同类型的二氢叶酸还原酶扩增产物。其中最大的(第一类扩增子)长度为273千碱基(Kb)。在本研究中，我们利用I型扩增子克隆作为探针，分析了其他五个独立分离的抗甲氨蝶呤中国仓鼠细胞系中扩增DNA序列的大小和变异性。我们的数据表明，除一个细胞外，所有这些细胞系中的主要扩增子类型都大于273kb的I型序列。凝胶内复性实验和用脉冲电场梯度凝胶电泳法分离的SfiI大片段的杂交分析表明，两个高抗性细胞系(A3和MK42)扩增出了长度至少为583和653 kb的高度同源的核心序列。因此，在不同耐药的中国仓鼠细胞系中，主要扩增子类型的大小可能不同。然而，与哺乳动物系统中其他几个DNA序列扩增的例子相比，给定的耐甲氨蝶呤的中国仓鼠细胞系在大小和序列排列上的异质性似乎较小。
We have previously cloned and characterized two different dihydrofolate reductase amplicon types from a methotrexate-resistant Chinese hamster ovary cell line (CHOC 400). The largest of these (the type I amplicon) is 273 kilobases (kb) in length. In the present study, we utilized clones from the type I amplicon as probes to analyze the size and variability of the amplified DNA sequences in five other independently isolated methotrexate-resistant Chinese hamster cell lines. Our data indicated that the predominant amplicon types in all but one of these cell lines are larger than the 273-kb type I sequence. In-gel renaturation experiments as well as hybridization analysis of large SfiI fragments separated by pulse-field gradient gel electrophoresis showed that two highly resistant cell lines (A3 and MK42) have amplified very homogeneous core sequences that are estimated to be at least 583 and 653 kb in length, respectively. Thus, the sizes of the major amplicon types can be different in different drug-resistant Chinese hamster cell lines. However, there appears to be less heterogeneity in size and sequence arrangement within a given methotrexate-resistant Chinese hamster cell line than has been reported for several other examples of DNA sequence amplification in mammalian systems.
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新的 DNA 重排与二氢叶酸还原酶基因扩增有关。
DOI：
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发表时间：
1984
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Federspiel,NA;Beverley,SM;Schilling,JW;Schimke,RT
通讯作者：
Schimke,RT
含有人类 N-myc 和 c-myc 基因的扩增单位。
DOI：
10.1073/pnas.83.4.1031
发表时间：
1986
影响因子：
11.1
作者：
Kinzler,KW;Zehnbauer,BA;Brodeur,GM;Seeger,RC;Trent,JM;Meltzer,PS;Vogelstein,B
通讯作者：
Vogelstein,B
通过高灵敏原位杂交方法定位叙利亚仓鼠染色体中的单拷贝和扩增 CAD 基因。
影响因子：
5.3
作者：
Wahl,GM;Vitto,L;Padgett,RA;Stark,GR
通讯作者：
Stark,GR
DOI：
10.1073/pnas.79.13.4083
发表时间：
1982-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
HEINTZ, NH;HAMLIN, JL
通讯作者：
HAMLIN, JL