Sorrentino B P, McDonagh K T, Woods D, Orlic D
Department of Biochemistry and Experimental Hematology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
Blood. 1995 Jul 15;86(2):491-501.
Transfer of the human multidrug resistance 1 (MDR1) gene to hematopoietic stem cells offers an approach to overcome the myelosuppression caused by a number of antineoplastic drugs. This study was designed to determine the effect of MDR1 gene transfer on overall P-glycoprotein (P-gp) expression in murine hematopoietic cells. Mice were transplanted with bone marrow cells infected with either of two different MDR1 retroviral vectors. A reverse-transcriptase polymerase chain reaction-based assay was used to quantify expression levels of both endogenous and vector-derived P-gp encoding transcripts in hematopoietic cells of transplanted mice. Expression of both a truncated and full-length MDR1 mRNA species was noted in bone marrow and spleen colony cells. The truncated message resulted from cryptic mRNA splice sites within the MDR1 cDNA and was detected with both vectors. Full-length message levels exceeded those from the endogenous genes in all but one case and roughly approximated that seen in the modestly drug-resistant cell line SW620. We conclude that transfer of MDR1 retroviral vectors resulted in a significant increase in P-gp expression in most cases; however, aberrant splicing of MDR1 transcripts can result in reduced expression of vector-derived P-gp.
将人类多药耐药1（MDR1）基因转移至造血干细胞为克服多种抗肿瘤药物引起的骨髓抑制提供了一种方法。本研究旨在确定MDR1基因转移对小鼠造血细胞中总体P-糖蛋白（P-gp）表达的影响。给小鼠移植感染了两种不同MDR1逆转录病毒载体之一的骨髓细胞。基于逆转录酶聚合酶链反应的检测方法用于定量移植小鼠造血细胞中内源性和载体衍生的P-gp编码转录本的表达水平。在骨髓和脾集落细胞中均检测到截短和全长MDR1 mRNA种类的表达。截短的信息来自MDR1 cDNA内的隐蔽mRNA剪接位点，两种载体均能检测到。除一种情况外，全长信息水平均超过内源性基因的水平，大致接近中度耐药细胞系SW620中的水平。我们得出结论，在大多数情况下，MDR1逆转录病毒载体的转移导致P-gp表达显著增加；然而，MDR1转录本的异常剪接可导致载体衍生的P-gp表达降低。
