Mukhamedkhanova F S, Kuznetsova N N, Nuridzhaniants S S, Abdurkarimov A A
Genetika. 1987 Sep;23(9):1588-94.
New sublines of BFFR1 and BFFR3 cells were obtained as a result of prolonged cultivation of Chinese hamster cells of Blld-ii-FAF 28 line (clone 431) in the presence of increasing concentrations of methotrexate (MTX). The lines obtained were resistant to 200 and 300 mcM of MTX, respectively. Amplification of the gene for dihydrofolate reductase (DHFR), similar to normal DHFR gene in restriction patterns, was proved by blot-hybridization of the resistant cells' DNA with 32P-labeled plasmid DHFR-26. Correlation is shown between the extent of gene amplification and resistance of the cell lines. In situ hybridization of the metaphase chromosomes of resistant cells with 3H-DHFR-26 results in preferential binding of the label with the regions of marker chromosomes 2 and 5, containing long, so called differential staining regions which are known to be the places of localization of amplified genes.
通过在浓度不断增加的甲氨蝶呤（MTX）存在下，对Blld-ii-FAF 28系（克隆431）的中国仓鼠细胞进行长期培养，获得了BFFR1和BFFR3细胞的新亚系。所获得的细胞系分别对200和300 μM的MTX具有抗性。通过用32P标记的质粒DHFR-26对抗性细胞的DNA进行印迹杂交，证实了二氢叶酸还原酶（DHFR）基因的扩增，其限制性图谱与正常DHFR基因相似。结果表明基因扩增程度与细胞系抗性之间存在相关性。用3H-DHFR-26对抗性细胞的中期染色体进行原位杂交，结果显示标记优先与2号和5号标记染色体区域结合，这些区域含有长的所谓差异染色区，已知这些区域是扩增基因的定位部位。
