Tonin P N, Stallings R L, Carman M D, Bertino J R, Wright J A, Srinivasan P R, Lewis W H
Cytogenet Cell Genet. 1987;45(2):102-8. doi: 10.1159/000132438.
We have shown previously that cDNAs for the M1 and M2 subunits of ribonucleotide reductase, ornithine decarboxylase (ODC), and p5-8, a 55,000-Dalton protein, hybridize to amplified genomic sequences in a highly hydroxyurea-resistant hamster cell line. We have extended these observations to include two additional, independently isolated, hydroxyurea-resistant cell lines: SC8, a single-step hamster ovary cell line, and KH450, a multistep human myeloid leukemic cell line, have also undergone genomic amplification for sequences homologous to ODC and p5-8 cDNAs. However, neither SC8 nor KH450 contains amplified genomic sequences homologous to an M1 cDNA probe. A panel of mouse-hamster somatic cell hybrids was used to map sequences homologous to M1, M2, ODC, and 5-8 cDNAs in the hamster genome. The M2, ODC, and p5-8 cDNAs hybridized to DNA fragments that segregated with hamster chromosome 7. In contrast, M1 cDNA hybridized to DNA fragments that segregated with hamster chromosome 3. These data suggest that the genes RRM2, (M2), ODC, and p5-8, but not RRMI (M1), are linked and may have been co-amplified in the selection of the hydroxyurea-resistant hamster and human cell lines.
我们先前已表明，核糖核苷酸还原酶的M1和M2亚基、鸟氨酸脱羧酶（ODC）以及一种55000道尔顿的蛋白质p5-8的cDNA，与一个高度耐羟基脲的仓鼠细胞系中的扩增基因组序列杂交。我们已将这些观察结果扩展至另外两个独立分离的耐羟基脲细胞系：SC8，一个单步仓鼠卵巢细胞系；以及KH450，一个多步人髓性白血病细胞系，它们也经历了与ODC和p5-8 cDNA同源的序列的基因组扩增。然而，SC8和KH450均不包含与M1 cDNA探针同源的扩增基因组序列。一组小鼠-仓鼠体细胞杂种被用于在仓鼠基因组中定位与M1、M2、ODC和p5-8 cDNA同源的序列。M2、ODC和p5-8 cDNA与随仓鼠7号染色体分离的DNA片段杂交。相反，M1 cDNA与随仓鼠3号染色体分离的DNA片段杂交。这些数据表明，基因RRM2（M2）、ODC和p5-8，但不包括RRMI（M1），是连锁的，并且在耐羟基脲的仓鼠和人细胞系的选择过程中可能已被共同扩增。
