Expressing Rac1N17.UAS under the control of Scer\GAL4elav-C155 in a witA12 background results in significantly fewer satellite boutons, but a similar number of mature synaptic boutons as controls at the NMJ of third instar larvae. The number of both bouton types is significantly reduced when expression is driven in a witA12/witB11 background.
The third instar larval neuromuscular junctions of individuals that both express Nrx-1Scer\UAS.cLa under the control of Scer\GAL4elav.PU and are witB11/witA12 transheterozygous show a decrease in the number of synaptic boutons similar to what is observed in witB11/witA12 transheterozygotes, rather than the increase induced by the expression of Nrx-1Scer\UAS.cLa.
witA12/witB11 fully suppresses the increase in mature boutons and branch number seen at the neuromuscular junction of Fmr1Δ113M/+ third instar larvae (branch number is significantly higher in witA12/witB11 larvae than Fmr1Δ113M/+;witA12/witB11 larvae).
Introducing a single copy of witA12 into the cpxSH1 mutant background also rescues the synaptic overgrowth but not the elevated minis, combination with witA12/witB11 reduces the number of NMJ boutons in cpxSH1 mutants even further, below the control levels and is comparable to that observed in witA12/witB11 mutants alone.
witA12 spartin1/witB11 Df(3R)110 double mutant larvae show a significant decrease in bouton number and satellite bouton number at the neuromuscular junction compared to controls, as occurs in witA12/witB11 single mutant larvae.
Expression of twitScer\UAS.cKa under the control of Scer\GAL4elav.PU slightly, but significantly, enhances the reduction in synaptic terminal size at the neuromuscular junction seen in witB11/witA12 larvae.
Expression of twitScer\UAS.cKa under the control of Scer\GAL4elav.PU has no effect on the size of the evoked excitatory junctional potential (EJP) at the neuromuscular junction in witB11/witA12 larvae.
Expression of twitScer\UAS.cKa under the control of Scer\GAL4elav.PU has no effect on miniature EJP (mEJP) amplitude at the neuromuscular junction in witB11/witA12 larvae, while mEJP frequency is slightly increased.
A witA12 heterozygous background can completely reverse the increase in total bouton number and satellite bouton formation in larvae expressing either Cip4NIG.15015R or WASpGD1559 post-synaptically (under the control of Scer\GAL4C57).
A witA12/witB11 transheterozygous background suppresses the synaptic overgrowth and increased bouton number phenotypes found in nwk1 homozygous third instar larvae, instead the larvae exhibit reduced synaptic growth and fewer boutons than wild type controls.
spictmut neuromuscular junction overgrowth phenotypes are fully suppressed in witA12/witB11 mutants. The synaptic undergrowth phenotypes in larvae homozygous for spictmut in a witA12/witB11 background are indistinguishable from that of witA12/witB11 mutants alone.
Expression of DysdsRNA.NH2.Scer\UAS postsynaptically (under the control of Scer\GAL4G14) in witA12/witB11 trans-heterozygous neuromuscular junctions results in similar EJP amplitudes and quantal content as in witA12/witB11 mutants.
At 25oC ~80% of witA12/witB11, FmrfScer\UAS.cMa (driven by Scer\GAL4dimm-929) animals can partially escape the pupal case. At 28oC about 30% of females fully eclose, and some inflate their wings. While these animals move fairly well they usually die within several days without producing progeny. No rescue is seen in the size of the synapse. Nor is the primary defect in synaptic transmission rescued.