Figure 5: Secreted TyrRS acts as a ‘find me’ signal for haemocytes.

(a–c) S2 cells transfected with act-gal4 plasmid alone (Control) or act-gal4 UAS-secTyrRS (secTyrRS), were plated on the lower compartment of the chemotaxis chamber. On the upper membrane of the transwell, S2 cells (red) were marked with CellTracker Red (Life Technologies) and incubated for 48 h. The number of cells that were attracted to the basal side of the transwell membrane was counted in six independent experiments. T-test *P<0.05. The secreted form of Drosophila TyrRS (secTyrRS) induces the attraction of haemocytes (Serpent, magenta) when is overexpressed in wild-type clones (GFP, green). (d–f). Scale, bar 10 μm. The same phenotype is achieved when secTyrRS or TyrRS is expressed in the dorsal compartment (apterous-gal4). In all, 24 wing discs were measured for each genotype (g–i). T-test *P<0.05. Knockdown of TyrRS in loser cells (GFP) (j,k) or control (LacZ) cells (m,n) 48 h after induction of super-competition. Scale bar 25 μm. Nuclei are marked in blue (4,6-diamidino-2-phenylindole (DAPI)). (l) Quantification of the number of haemocytes in discs with super-competition clones, 21 wing discs were measured for each genotype. Quantification of the number of clones (o) or size of the clones (p) during cell competition 48 ACI between LacZ expressing clones (LacZ) and TyrRS RNAi-expressing clones. T-test *P<0.05, NS, non significant; n=10 discs.