Pan-neuronal expression of Mmus\Prnp^{Scer\UAS.T:Hsap\PRNP-3F4} under the control of Scer\GAL4^elav-C155 results in functional changes in the NMJ. There is an increase in mean miniature excitatory junctional current (mEJC) amplitude compared with wild type and this is caused by an increase in mean synaptic vesicle size compared to control in both type 1s and 1b boutons. Ca[2+]-dependent evoked EJC amplitudes are enhanced upon expression of Mmus\Prnp^{Scer\UAS.T:Hsap\PRNP-3F4}. Mmus\Prnp^{Scer\UAS.T:Hsap\PRNP-3F4} enhances synaptic release probability and quantal content (the number of vesicles released per action potential) but reduces the size of the ready-releasable vesicle pool. No morphological changes are observed in the NMJs: the NMJs are a similar size and contain a similar amount of brp+ active zones as controls.

Expression of Mmus\Prnp^{Scer\UAS.T:Hsap\PRNP-3F4} under the control of Scer\GAL4^elav-C155 causes an increase in larval locomotor activity compared to controls, as detected in greater crawling distances.

Expression of Mmus\Prnp^{Scer\UAS.T:Hsap\PRNP-3F4} driven by Scer\GAL4^αTub84B.PL does not induce defects in climbing ability.