Figure 3: Activin-β promotes hemocyte proliferation.
From: Regulation of Drosophila hematopoietic sites by Activin-β from active sensory neurons
(a,b) Control (HmlΔ-DsRed (red), and overexpression of Actβ in PNS neurons by 21-7-GAL4 with hemocytes HmlΔ-DsRed (red). Whole larvae lateral view (top panel), and closeup (lower panel). (c,d) Control and ectopic expression of Actβ in ventral epidermis and oenocytes using the driver Sal-GAL4 (GMR85E05-GAL4) marked by UAS-GFP (green), and hemocytes HmlΔ-DsRed (red). Whole larvae lateral view (top panel), and closeup (lower panel). (e,f) Same as in (c,d) but combined (red, green) and single channels (green) of close-up images shown. (g) Total hemocyte counts per larva, genotypes are 21-7-GAL4, UAS-mCD8GFP, HmlΔ-DsRed/+; UAS-Actβ/+ (control is 21-7-GAL4, UAS-mCD8GFP, HmlΔ-DsRed/+), n=4, seen with two different transgenes (n=8 total); and HmlΔ-DsRed/+; Sal-GAL4, UAS-GFP/UAS-Actβ, (control is HmlΔ-DsRed/+; Sal-GAL4, UAS-GFP/+), n=5 to 6. (h) Hemocytes in circulation, genotypes and n as in g. (i) In vivo EdU incorporation, genotypes 21-7-GAL4, UAS-mCD8GFP, HmlΔ-DsRed/+ (control) and 21-7-GAL4, UAS-mCD8GFP, HmlΔ-DsRed/+; UAS-Actβ (III)/+; n=36 for larvae 60–70 h AEL (2.0–2.4 mm), and n=8 for larvae 71–83 h AEL (2.5–2.9 mm). (j) In vivo EdU incorporation, HmlΔ-GAL4, UAS-GFP; He-GAL4 x yw (control); x UAS-put RNAi and UAS-dSmad2 RNAi (experiment larvae); n=6; larvae 46–52 h AEL (1.5–1.7 mm). (k) EdU incorporation of released larval hemocytes stimulated with Actβ ex vivo; genotype HmlΔ-GAL4, UAS-GFP; He-GAL4; average over 4 independent experiments (Actβ +/− conditioned media from 2 cell lines in 2 replicates each). Scale bars, a (upper panel), 0.5 mm; a (lower panel), 0.2 mm. Error bars represent s.d., and two-tailed t-test values correspond to NS (not significant) P>0.05; *P≤0.05; **P≤0.01; ***P≤0.001; ****P≤0.0001.
