Expression of mdr49 and mdr65 multidrug resistance genes in larval tissues of Drosophila melanogaster under normal and stress conditions

Abstract

In situ expression of 2 multidrug resistance genes, mdr49 and mdr65, of Drosophila melanogaster was examined in wild-type third instar larval tissues under physiological conditions and after heat shock or colchicine feeding. Expression of these 2 genes was also examined in tumorous tissues of lethal (2) giant larvae l(2)gl 4 mutant larvae. These 2 mdr genes show similar constitutive expression in different larval tissues under physiological conditions. However, they are induced differentially by endogenous (tumorous growth) and exogenous stresses (colchcine feeding or heat shock): whereas heat shock and colchicine feeding induce mdr49, tumorous condition is accompanied by enhanced expression of mdr49 and mdr65 genes.

Transepithelial transport of fluorescent p-glycoprotein and MRP2 substrates by insect Malpighian tubules: confocal microscopic analysis of secreted fluid droplets

“…Demonstration of secretion of P-gp and MRP2 substrates by Drosophila tubules is of particular interest because of previous molecular genetic evidence for the presence of MDR and MRP genes in this species (Wu et al, 1991;Tarnay et al, 2004). Our results set the stage for further analysis of the effects of treatments, such as cadmium exposure and heat shock (Tapadia and Lakhotia, 2005), known to alter MRP or MDR gene expression on transport of P-gp and MRP2 substrates by isolated MTs and the possible role of such transport in insecticide resistance. In view of recent evidence showing modulation of organic cation transport by dietary loading, peptides, amines and intracellular second messengers , it will also be of interest to examine whether transport of P-gp and MRP2 substrates is also modulated by such treatments.…”

Too much of a good thing: how insects cope with excess ions or toxins in the diet

“…Three MDR genes (MDR49, MDR50, MDR65) are found in Drosophila and there is expression along much of the length of the gut and the Malpighian tubules, again pointing to a significant role for the gut in the transport of Pglycoprotein substrates. MDR expression is enhanced by treatments such heat shock (Tapadia and Lakhotia, 2005).…”

Multidrug resistance protein gene expression inTrichoplusia nicaterpillars

“…Three genes coding for ABC‐B family proteins have been identified in Drosophila melanogaster (Wu et al ., ; Gerrard et al ., ) and a fourth can be found in its genome in silico . Induction of mRNA expression of one of these genes, mdr49 , has been observed in response to feeding with colchicine (Tapadia & Lakhotia, ). Chahine & O'Donnell () have further shown that expression of these genes, as well as those for other transporters, is increased by feeding of methotrexate.…”