View Program - 63rd Annual Drosophila Research Conference

Thermal tolerance of an organism depends on both its ability to dynamically adjust to a thermal stress and preparatory processes that enhance resistance to extreme temperatures (either cold or hot). However, our understanding of the molecular mechanisms that underpin these acclimatization processes is limited—especially for the cold. It has been previously shown that cold acclimated flies are better able to maintain ion homeostasis and fluid reabsorption across the hindgut epithelium in extreme cold. We had previously conducted a GWAS analysis of the critical thermal minimum (CTmin) in the Drosophila Genetic Reference Panel (DGRP), which identified two single nucleotide polymorphisms (SNPs) in the first intron of Lgr1, a a G-protein coupled receptor (GPCR) expressed predominantly in the hindgut. Baseline Lgr1 expression was higher in flies raised at colder temperatures as adults, suggesting that changes in Lgr1-mediated signaling may be involved in conferring cold stress resistance. To test this hypothesis, expression of Lgr1 was knocked down with Gal4 driving RNAi expression in hindgut. Lgr1 knockdown significantly impaired baseline CTmin in both sexes, and in males, which express ~6X higher Lgr1 under baseline conditions, knockdown reduced cold acclimation capacity. Altogether, this suggests that Lgr1 may play an important role in driving hindgut reabsorption during cold stress. Future studies will focus on elucidating Lgr1 interactors and identifying its part in the preparatory physiological processes changing to maintain homeostasis in the extreme cold.

Dynamic expression of Lgr1 in the hindgut suggests a role in cold tolerance and acclimation