ACP-GAG binding promotes GBS invasion into fly heads; glial GAG polymerase knock-down decreases lethal infection.

(A) The ratio of head/whole fly cfu in WT yw flies 24 h after infection with GBS mutant R185A (filled bar, n = 13 groups of 10 flies) was significantly lower than after infection with WT GBS strain A909 (open bar, n = 14 groups of 10 flies). (B) The ratios of head to whole fly cfu in HSPG mutant flies (filled bars) were lower than those in the WT control flies (open bar, n = 22 groups of 10 flies). The HSPG mutant flies studied here carry mutations in the genes encoding core proteins (dally+dlp+sdc, n = 15 groups of 10 flies), GAG polymerases (ttv+sotv, n = 12 groups of 10 flies) or the GAG NDST (sfl, n = 10 groups of 10 flies. Infected flies were heterozygotes from crosses of these mutants with yw flies, as homozygous mutants in these genes are nonviable. Each bar represents the mean and SEM. The student's t-test was used for statistical analysis in each comparison. ** p<0.01; *** p<0.001. Repo-Gal4 is a pan-glial Gal4 driver [66]. Flies expressing shRNA targeting both ttv and sotv (C) or botv alone (D) driven by repo-Gal4 show resistance to lethal A909 infection. Plots show a pool of data from at least 60 flies per sample. The genotypes of the flies used here are repo-Gal4/+ (repo), UAS-sotvRNAi/+;UAS-ttvRNAi/+ (sotvRNAi+ttvRNAi), UAS-sotvRNAi/+;UAS-ttvRNAi/repo-Gal4 (repo>sotvRNAi+ttvRNAi), UAS-botvRNAi/+ (botvRNAi) and UAS-botvRNAi/repo-Gal4 (repo>botvRNAi). The Gal4 and UAS lines were crossed with yw flies as controls. The survival curves of yw, Gal4 controls, UAS controls, and shRNA expressing groups are indicated as open circles, open squares, open diamonds, and filled circles respectively. A log rank test was used for statistical analysis in comparing shRNA-expressing groups and control groups.