Overexpression of necdin ameliorates the motor axon outgrowth phenotype in smn morphant zebrafish.
(A) Western blotting of cytochrome C, an electron transport chain protein showed an increase in NDN overexpressing embryos suggesting an increase in mitochondrial biogenesis. (B) Cyt C protein levels were quantified relative to a loading control. (C) Representative confocal micrographs of motor neuron axons exiting the spinal cord in control (top), smn morphant (middle) and smn morphant over-expressing Ndn (bottom) Tg(hb9:GFP) zebrafish embryos. Note the presence of the axonal outgrowth phenotype associated with smn knockdown (arrow heads) is reduced in the Ndn expressing animals. Scale bars = 50 μM. (D) Bar chart (mean & s.e.m.) showing a significant increase in the number of normal MNs, and a concomitant significant decrease in the number of severely affected MNs, in co-injected smn MO and Ndn mRNA embryos compared to single smn MO injected embryos at 30 hpf. Unpaired two-tailed student t-tests; * p<0.05, ** p<0.01 *** p<0.001. N = 20 embryos per experimental group.