Larval brains with expression of Nrx-IVEP604 driven by Scer\GAL4elav.PU show significantly increased staining intensity of the presynaptic protein brp; this is dosage dependent, with two copies of Nrx-IVEP604 resulting in further increases in intensity. At the neuromuscular junction, Scer\GAL4elav.PU>Nrx-IVEP604 larvae show a significant increase in bouton number (and boutons are smaller), increase in active zone number (per synaptic area) and increase in branches (per synaptic terminal), compared to controls.