Sequence of mdr3 cDNA encoding a human P-glycoprotein.

摘要: We have determined the sequence of human mdr3 gene using cDNA derived from liver RNA. The codes for a member family membrane proteins, P-glycoproteins, overproduced in many multi-drug-resistant (MDR) cell lines. Like its relatives, protein encoded by has deduced Mr 140,000, which is presumably increased glycosylation after synthesis. consists two similar halves, each with series six hydrophobic segments that may form channel. halves also possess nucleotide-binding consensus sequences, act as ATPases and drive drug transport. presumed ATPase domains are all but identical to those mdr1 product [Chen et al., Cell 47 (1986) 381-389]. attribute this high level conservation repeated conversion evident differ only few silent mutations. Divergence between P-glycoprotein members greatest at N terminus 60 amino acid linker connecting halves. In putative trans-membrane approx. 80% acids conserved products mdr3. Although function not yet known, homology suggests it encodes an efflux pump broad specificity.