A P-GLYCOPROTEIN PROTECTS CAENORHABDITIS-ELEGANS AGAINST NATURAL TOXINS

P-glycoproteins can cause resistance of mammalian tumor cells to chemo therapeutic drugs. They belong to an evolutionarily well-conserved fam ily of ATP binding membrane transporters. Four P-glycoprotein gene hom ologs have been found in the nematode Caenorhabditis elegans; this rep ort describes the functional analysis of two, We found that PGP-3 is e xpressed in both the apical membrane of the excretory cell and in the apical membrane of intestinal cells, whereas PGP-1 is expressed only i n the apical membrane of the intestinal cells and the intestinal valve . By transposon-mediated deletion mutagenesis we generated nematode st rains with deleted P-glycoprotein genes and found that the pgp-3 delet ion mutant, but not the pgp-1 mutant, is sensitive to both colchicine and chloroquine. Our results suggest that soil nematodes have P-glycop roteins to protect themselves against toxic compounds made by plants a nd microbes in the rhizosphere.