Hörnberg, H., Wollerton-van Horck, F., Maurus, D., Zwart, M., Svoboda, H., Harris, W.A., and Holt, C.E. (2013) RNA-Binding Protein Hermes/RBPMS Inversely Affects Synapse Density and Axon Arbor Formation in Retinal Ganglion Cells In Vivo. The Journal of neuroscience : the official journal of the Society for Neuroscience. 33(25):10384-10395.
The RNA-binding protein Hermes [RNA-binding protein with multiple splicing (RBPMS)] is expressed exclusively in retinal ganglion
cells (RGCs) in the CNS, but its function in these cells is not known. Here we show that Hermes protein translocates in granules
from RGC bodies down the growing axons. Hermes loss of function in both Xenopus laevis and zebrafish embryos leads to a significant reduction in retinal axon arbor complexity in the optic tectum, and expression
of a dominant acting mutant Hermes protein, defective in RNA-granule localization, causes similar defects in arborization.
Time-lapse analysis of branch dynamics reveals that the decrease in arbor complexity is caused by a reduction in new branches
rather than a decrease in branch stability. Surprisingly, Hermes depletion also leads to enhanced early visual behavior and
an increase in the density of presynaptic puncta, suggesting that reduced arborization is accompanied by increased synaptogenesis
to maintain synapse number.