IDENTIFICATION OF P-GLYCOPROTEIN MULTIDRUG-RESISTANCE GENES FROM MODEL ORGANISMS

Using degenerate oligonucleotides from conserved portions of the ATP-b inding domain of the active transporter genes, several new members of this gene superfamily have been cloned from Drosophila, Saccromyces ce revisiae, and E. coli DNA. The Drosophila and E. coli genes contain tw o sets of transmembrane domains and two ATP-binding domains, whereas t he-yeast gene contains single transmembrane and ATP binding domains. A ll three genes show a high degree of similarity to the mammalian P-gly coprotein/multidrug resistance (MDR) genes. The E. coli sequence is th e only known transporter gene containing both ATP and transmembrane do mains in a single open reading frame. While the function of these sequ ences has not been determined, they may prove to be useful for develop ing a model to study the function of P-glycoproteins.