Overexpression and amplification of five genes in a multidrug-resistant Chinese hamster ovary cell line.

摘要: Abstract Multidrug-resistant cells are cross-resistant to a wide range of unrelated drugs, many which used in cancer chemotherapy. We constructed cDNA library from RNA the multidrug-resistant Chinese hamster ovary cell line CHRC5. By differential screening we isolated cDNAs derived mRNAs that overexpressed this line. The could be grouped five classes on basis transcript lengths detected blots. infer each class codes for separate protein. corresponding genes amplified 10 or 30 times CHRC5 DNA, providing an explanation constitutive overexpression found Despite amplification, may linked one large amplicon as indicated by hybridization analysis fragments DNA separated pulsed field gradient gel electrophoresis. Therefore, some these might fortuitously coamplified and not contribute functionally resistant phenotype. It is also possible, however, involved drug resistance clustered. One our clones cross-hybridized with recently described pCHP1 (J. R. Riordan, K. Deuchars, N. Kartner, Alon, J. Trent, V. Ling, Nature [London] 316:817-819, 1985) encoding part 170-kilodalton P-glycoprotein, protein frequently overproduced cells. nature four other still unknown. Sequences conserved mouse human DNA.