Fig. 1

Microglia morphology of RNASET2-deficient embryos and larvae. Zebrafish of the transgenic reporter strain Tg:(PU1:GFP) were analyzed by in vivo CLSM. The morphology of microglia together with their total numbers was determined manually by going stepwise through the confocal z-stacks of individual larvae. These key figures were categorized, quantified and shown as averages in the respective graphs. Thus, the images shown here were selected to highlight the morphology of microglia and should not be used to deduce cell numbers or relative proportions. (A,C,E,G) Projections of confocal z-stacks through the brain showing microglia (green, arrows indicate abnormally vacuoled microglia). (B,D,F,H) Single optical sections at increased size as in the respective left panel, showing ramified and vacuoled microglia (arrows indicate abnormally vacuoled microglia). (I,J) Quantification of the morphological categories of microglia on 3 dpf (ramified mean: WT 23.2%; s.d.=22.8; n=14; mutants 3.2%; s.d.=7.0; n=9; P<0.5; vacuoled mean: WT 48.8%; s.d. 22.8; n=14; mutants 55.7%; s.d.=21.3; n=9; P>0.5) and 5 dpf (ramified mean: WT 56.9%; s.d.=23.0; n=12; mutants 5.8%; s.d.=6.6; n=14. Vacuoled mean: WT 13.3%; s.d.=14.8; n=12; mutants 85.2%; s.d.=8.7; n=14), respectively. (K,L) Averaged counts of microglia within the optical tectum on 3 dpf (mutants 10.4; s.d.=3.1, n=8; WT 12.5; s.d.=3.8; n=12; P>0.05) and 5 dpf (mutants 18.1; s.d.=7.9, n=14; WT 11.3; s.d.=8.2; n=12; P<0.05). Dotted lines, midbrain-hindbrain boundary; straight line, midline, separating left and right brain hemispheres. Scale bars: A,C,E,G: 40 µm; B,D,F,H 10 µm. n-numbers were generated from >7 individual litters and analyzed in seven independent CLSM-sessions.