Inhibition of zfPGRN-A translation resulted in the generation of shorter axons and stalling of CaP Motor Neurons (MNs) at the horizontal myoseptum.
Fig 1A Inhibition of zfPGRN-A translation produced truncated axons in live zebrafish. Compared to control (A1), zfPGRN-A knockdown produced shorter axons (A2) that were rescued by hPGRN mRNA (A3) while hPGRN alone did not produce truncated axons but increased branching (A4). Lateral views (anterior to the left; dorsal to the top) of embryos obtained from the Hb9:GFP transgenic fish. Images were captured at 5X magnification and the hatched box was further subject to 4-5X Zoom. Dashed lines represent the horizontal myoseptum (HM). The double- headed arrows represent increased branching and the white arrow represents axonal length.Fig 1B Expression of the short form zebrafish granulin zfPGRN-1 did not reverse the phenotype due to zfPGRN-A knockdown. B1. zfPGRN-1 did not rescue locomotor defects produced by the knockdown of zfPGRN-A assessed by employing touch evoked swimming test. B2 zfPGRN-1 did not rescue motor axon defects produced by zfPGRN-A Knockdown. The ability of PGRN mRNA to rescue motor neuron defects in zebrafish is therefore limited to some but not all PGRN proteins. MN axonal length from the specified areas in the spinal cord region was measured using imageJ by tracing the labelled MN axons.