Simultaneous expression of pumScer\UAS.fl and eIF-4EScer\UAS.cRa in muscles (using Scer\GAL4Mhc.Switch.PO) results in the increase in 1b bouton number conferred by overexpressing eIF-4EScer\UAS.cRa being completely suppressed by the overexpression of pumScer\UAS.fl. 1b bouton numbers in larvae overexpressing both eIF-4EScer\UAS.cRa and pumScer\UAS.fl are not significantly different from those in larvae overexpressing only pumScer\UAS.fl.
Expression of pumScer\UAS.fl at 18oC in postmitotic neurons (Scer\GAL4elav-C155) rescues the synaptic morphology phenotypes found in a pum9/pum7 background. Both the average size and the number of type 1b boutons on muscle 12 are restored to wild-type.
Expression of pumScer\UAS.fl in muscles (Scer\GAL4Mhc.Switch.PO) in pum9/pum7 larvae reduces the number of eIF-4E aggregates by 7-fold, to 3.5 aggregates per neuromuscular junction. The level of eIF-4E is reduced by approximately 6.5-fold. In contrast, neural expression of pumScer\UAS.fl (Scer\GAL4elav-C155) in pum9/pum7 larvae does not greatly decrease the number of eIF-4E aggregates (although a 20% reduction is seen). Levels of eIF-4E are 88% of those in pum9/pum7 larvae.
The increase in 1s bouton number in pum9/pum7 mutants is fully rescued through expression of pumScer\UAS.fl in muscles (Scer\GAL4Mhc.Switch.PO), and is unaffected by expression in neurons (under the control of Scer\GAL4elav-C155).
The mEJP amplitude and quantal content phenotypes of pum9/pum7 mutants are not rescued to near wild-type levels by neuronal (Scer\GAL4elav-C155), muscle (Scer\GAL4Mhc.Switch.PO), or dual expression of pumScer\UAS.fl.