Subclonal heterogeneity of the multidrug resistance phenotype in a cell line expressing antisense MDR1 RNA.
Subclonal heterogeneity of the multidrug resistance phenotype in a cell line expressing antisense MDR1 RNA.
复制标题
表达反义 MDR1 RNA 的细胞系中多药耐药表型的亚克隆异质性。
DOI：
10.1007/bf02255838
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Dolnick,BJ
中科院分区：
文献类型：
--
作者：
Hanchett,LA;Baker,RM;Dolnick,BJ
A multidrug resistant (MDR) cell line was transfected with an antisense MDR1 expression vector and transfectant clones were analyzed for reversion of the MDR phenotype. Only one of 10 antisense-expressing transfectants showed a reduction in drug resistance, MDR1 mRNA and P-glycoprotein. Observations made using rhodamine-123, a fluorescent substrate for P-glycoprotein, revealed that dye retention in individual cells was highly variable within this antisense-expressing clone. Subpopulations were established from the original clone based on differences in rhodamine-123 retention. Rhodamine-123 retention varied inversely with levels of P-glycoprotein and MDR1 mRNA. All subpopulations expressed similar levels of antisense MDR1 RNA yet had dramatic differences in MDR1 mRNA levels. Analysis of vector integration site restriction fragment length polymorphisms confirmed that all populations originated from the same transfectant clone. Nuclear run-on analysis indicated that themdr1gene is transcribed at the same rate in all populations, suggesting that the reduction in MDR1 mRNA is mediated posttranscriptionally. Cells with the greatest reduction in MDR1 mRNA accumulate distinct antisense RNA transcripts in the nuclear RNA fraction, suggesting that antisense effectiveness in this system is associated with a nuclear event or process. These results reveal that antisense RNA activity is not necessarily distributed equally within a clonal populations.
