Pleiotropic and novel phenotypes in the Drosophila gut caused by mutation of drop-dead

Abstract

Normal gut function is vital for animal survival, and deviations from such function can contribute to malnutrition, inflammation, increased susceptibility to pathogens, diabetes, neurodegenerative diseases, and cancer. In the fruit fly Drosophila melanogaster, mutation of the gene drop-dead (drd) results in defective gut function, as measured by enlargement of the crop and reduced food movement through the gut, and drd mutation also causes the unrelated phenotypes of neurodegeneration, early adult lethality and female sterility. In the current work, adult drd mutant flies are also shown to lack the peritrophic matrix (PM), an extracellular barrier that lines the lumen of the midgut and is found in many insects including flies, mosquitos and termites. The use of a drd-gal4 construct to drive a GFP reporter in late pupae and adults revealed drd expression in the anterior cardia, which is the site of PM synthesis in Drosophila. Moreover, the ability of drd knockdown or rescue with several gal4 drivers to recapitulate or rescue the gut phenotypes (lack of a PM, reduced defecation, and reduced adult survival 10-40 days post-eclosion) was correlated to the level of expression of each driver in the anterior cardia. Surprisingly, however, knocking down drd expression only in adult flies, which has previously been shown not to affect survival, eliminated the PM without reducing defecation rate. These results demonstrate that drd mutant flies have a novel phenotype, the absence of a PM, which is functionally separable from the previously described gut dysfunction observed in these flies. As the first mutant Drosophila strain reported to lack a PM, drd mutants will be a useful tool for studying the synthesis of this structure.

A gene-specific T2A-GAL4 library for Drosophila

“…Finally, numerous other manipulations based on GAL4/UAS technology can be explored to assess function including those of species homologues, to query neuronal connectivity, impair activity, ablate cells, or assess gene or cellular functions, as well as various other applications ( Kanca et al, 2017 ; Venken et al, 2011b ). So far, about 50 genes have been reported to be tagged with a Trojan-GAL4 cassette ( Chao et al, 2017 ; Conway et al, 2018 ; Diao et al, 2015 ; Diao et al, 2016 ; Hattori et al, 2017 ; Krüger et al, 2015 ; Lee et al, 2018 ; Li et al, 2017 ; Liu et al, 2017 ; Poe et al, 2017 ; Skeath et al, 2017 ; Toret et al, 2018 ; Wu et al, 2017 ; Yoon et al, 2017 ). Hence, the power and generality of this technology remains to be explored.…”

The Drosophila drop-dead gene is required for eggshell integrity

“…The aberrant splicing replaces the final 76 residues of the 827 amino acid Drd protein with a novel sequence. drd 1 has previously been shown to cause the same short adult lifespan, female sterility, and absence of a peritrophic matrix as drd lwf , a nonsense mutation that eliminates all but the first 180 amino acids [ 38 , 40 ]. Thus, our finding highlights the importance of the C-terminal of Drd in protein function, stability, or localization.…”

“…hs = FRT(w hs )}101 (FBst0001844, RRID:BDSC_1844)), were obtained from the Bloomington Drosophila Stock Center. Creation of the drd-GAL4 driver transgene has been reported previously [ 40 ]. The genes and alleles referenced in this work include drd (FBgn0260006), drd lwf (FBal0193421), drd 1 (FBal0003113).…”

TheDrosophila drop-deadgene is required for eggshell integrity

“…Other stocks (w 1118 ; P{UAS-GFP.nls}14 (FBst0004775, RRID:BDSC_4775), P{w +mW.hs =GawB}T155 (FBst0005076, RRID:BDSC_5076, referred to as T155-GAL4), w* ovo D1 v 24 P{w +mW.hs =FRT(w hs )}101/C(1)DX, y 1 f 1 ; P{ry +t7.2 =hsFLP}38 (FBst0001813, RRID:BDSC_1813), and y 1 w* v 24 P{w +mW.hs =FRT(w hs )}101 (FBst0001844, RRID:BDSC_1844)), were obtained from the Bloomington Drosophila Stock Center. Creation of the drd-GAL4 driver transgene has been reported previously (36). The genes and alleles referenced in this work include drd (FBgn0260006), drd lwf (FBal0193421), drd 1 (FBal0003113).…”

“…drd encodes a putative integral membrane protein of unknown function with homology to prokaryotic acyltransferases (34). Mutation of drd causes a wide range of phenotypes, including female sterility, early adult death and neurodegeneration, defective food movement through the gut, and absence of a peritrophic matrix from the midgut (35)(36)(37)(38)(39). The basis for female sterility has not previously been reported.…”