Increased synaptic density and axon branching in the CNS of fmr1-/- embryos.

A. Wide-angled view of a confocal generated image of a single motor neuron in a 2 dpf embryo, which transiently expresses mnx1X3:GAL4 and uas:tRFP constructs. DLAV, dorsal lateral anastomotic vessel; N, notochord; NT, neural tube; PVC, posterior cardinal vein; S, somite. B-C. Confocal imaging of motor neurons in 2 dpf fmr1-/- and WT embryos, which transiently express mnx1X3:GAL4 and uas:memYFP constructs. D-E. Total arbor length (D) and number of branches (E) were measured in fmr1-/- (grey bars) and WT (white bars) embryos (WT, n = 17; fmr1-/-, n = 27, *p.05). Values are represented as means ± SEM. F-G. Confocal imaging of motor neurons in 2 dpf fmr1-/- and WT embryos, which transiently express mnx1X3:GAL4, uas:SYP-EGFP and uas:tRFP constructs. H. Total synaptic density was measured along the last 10 μm of a single branch of motor neurons in fmr1-/- and WT embryos (WT, n = 11; fmr1-/-, n = 17, *p.05). Scale bar = 10 μm. Values are represented as means ± SEM. I-J. Confocal imaging of spinal Rohon-Beard (RB) sensory neurons that project dorsally in 2 dpf fmr1-/- and WT embryos, which transiently express huc:GAL4 and uas:memYFP constructs. K-L. The total arbor length (K) and number of branches (L) in the arbor of RB neurons were quantified in fmr1-/- and WT embryos (WT, n = 9; fmr1-/-, n = 10, *p.05). M-N. Confocal imaging of RB neurons in 2 dpf fmr1-/- and WT embryos, which transiently express huc:GAL4, uas: SYP-EGFP and uas:tRFP constructs. O. Total synaptic density was measured along the last 30 μm of a single branch of RB neurons in fmr1-/- (grey bars) and WT (white bars) embryos (WT, n = 10; fmr1-/-, n = 13). Scale bar = 30 μm. Values are represented as means ± SEM. Statistical significance was determined by two-sample t-test assuming unequal variances. P. Dorsal view of Hcrt neuron axons in a 2 dpf embryo, which transiently expresses the hcrt:SYP-EGFP construct. White arrow indicates the area analyzed. Q-R. Representative confocal imaging of Hcrt axons in 2 dpf fmr1-/- and WT embryos, which transiently express the hcrt:SYP-EGFP construct. S. Total synaptic density was measured along the last 10 μm of a single axonal branch of hcrt neurons in fmr1-/- and WT embryos (WT, n = 8; fmr1-/-, n = 9, *p.05). Scale bar = 10 μm. Values are represented as means ± SEM.