Expression of stasScer\UAS.cLa either pan-neuronally under the control of Scer\GAL4n-syb.PS or in cholinergic neurons using Scer\GAL4Cha.7.4 rescues the increase in neuromuscular junction evoked excitatory postsynaptic potential (eEPSP) amplitudes seen in SmnX7 mutant larvae. The reduction in muscle size is rescued to 80% of that in control larvae. Expression of stasScer\UAS.cLa in the glutamatergic motor neurons using the Scer\GAL4VGlut-OK371 driver fails to rescue either the eEPSP or muscle size phenotypes. The locomotor activity defects seen in SmnX7 mutants are not rescued by any of the three drivers.
Decreased muscle surface area, locomotor defects, increased inter-spike intervals and increased evoked excitatory postsynaptic potential (eEPSP) amplitude in SmnX7/SmnX7 third instar larvae are rescued by ubiquitous (Scer\GAL4da.PU), pan-neuronal (Scer\GAL4nSyb.PS) or cholinergic (Scer\GAL4ChAT.7.4) expression of SmnScer\UAS.T:Zzzz\FLAG; these phenotypes are not rescued when expression is driven by larval muscle-specific Scer\GAL4G14, glutamatergic Scer\GAL4VGlut-OK371, motor-neuron specific Scer\GAL4RapGAP1-OK6, GABAergic (Scer\GAL4Gad1.3.098), Scer\GAL41003.3 or Scer\GAL4ppk.1.9. Expression of SmnScer\UAS.T:Zzzz\FLAG with Scer\GAL4clh201 or Scer\GAL4NP2225 rescues the increased inter-spike intervals and increased eEPSP amplitude, partially rescues the decreased muscle surface area, but fails to rescue the locomotion defect in SmnX7/SmnX7 third instar larvae.
SmnScer\UAS.T:Zzzz\FLAG driven by Scer\GAL4elav.Switch.PO in the presence of RU486 rescues SmnX7/SmnX7 muscle size, locomotion (partially), inter-spike intervals and eEPSP defects if SmnScer\UAS.T:Zzzz\FLAG expression is induced immediately after hatching (if induced 48 or 96 hours after hatching rescue is partial apart from full rescue of eEPSP).
Expression of SmnT:Zzzz\FLAG in a Smnf01109/SmnX7 mutant background results in >70% rescue of lethality. The resulting adults are fertile with no apparent defects in flight or motility. Pupation and eclosion occurs a day later than in wild type controls. Expression of SmnT:Zzzz\FLAG also rescues the motility and burrowing defects seen in Smnf01109/SmnX7 mutant larvae.
Expression of SmnT205I.T:Zzzz\FLAG fully rescues the larval lethality seen in Smnf01109/SmnX7 mutants. However lethality in these mutants occurs at the pupal stage, with only 25% of mutants eclosing as adults. Pupation and eclosion occurs a day later than in wild type controls. Expression of SmnT:Zzzz\FLAG also largely rescues the motility defects seen in Smnf01109/SmnX7 mutant larvae, whereas the burrowing defects are fully rescued.