The expression of CaMKIIT287D.Scer\UAS under the control of Scer\GAL4Toll-6-D42 leads to significant increases in the number of type Ib boutons, in the axonal length and in the number of active zones at the larval neuromuscular junction, as compared to controls.
Expression of CaMKIIT287D.Scer\UAS in the RP2 motor neurons (using the Scer\GAL4eve.RRK driver to drive expression of Scer\FLP1Scer\UAS.cUa which then induces clones of cells expressing Scer\GAL4Act.PU) results in an increase in total dendrite length compared to controls, while dendrite number if not significantly affected. The overall pattern of branching is changed such that there are a greater number of branches closer to the neuronal soma.
Expression of CaMKIIT287D.Scer\UAS in the motor neurons under the control of Scer\GAL4D42 increases bouton number by approximately 30% and significantly increases motor axon diameter (by approximately 40%).
CaMKIIT287D.Scer\UAS expression decreases EJP amplitude while having no effect on mEJP amplitude.
Expression of CaMKIIT287D.Scer\UAS under the control of Scer\GAL4how-24B has no effect on the area of the presynaptic terminal at the larval neuromuscular junction.
The mean amplitude of the excitatory junctional potential (EJP) at the neuromuscular junction is unchanged compared to controls in larvae expressing CaMKIIT287D.Scer\UAS under the control of Scer\GAL4how-24B. The mean amplitude of spontaneous miniature EJPs at the mutant neuromuscular junction is reduced compared to controls. The quantal content is significantly elevated in the mutant larvae at both 0.4 and 1.5mM extracellular Ca[2+].
CaMKIIT287D.Scer\UAS expression, under the regulation of Scer\GAL4109(2)80 results in significant increases in dendritic filopodia density in class III neurons. This phenotype is confined to the dendritic compartment of class III neurons, as no filopodia are formed on the axon shafts, and becomes more severe with increasing transgene number. Increasing the transgene number increases the number of filopodia formed without substantially changing the length/number distribution. The CaMKIIT287D.Scer\UAS phenotype does not become apparent until the second instar stage, becoming more prominent later in development. CaMKIIT287D.Scer\UAS expression, under the regulation of Scer\GAL4109(2)80 dramatically increases the numbers of newly formed and disappearing filopodia during development. Larvae expressing CaMKIIT287D.Scer\UAS, under the regulation of Scer\GAL4109(2)80, show a dramatic increase in the post-diffusion turnover of Act5CScer\UAS.T:Avic\GFP with a clear statistically significant shift relative to wild-type.
In neuromuscular junctions of CaMKIIT287D.Scer\UAS; Scer\GAL4Mef2.PR larvae the size of amplitude excitatory postsynaptic potentials (EPSPs) and the amplitude and frequency and kinetics of mini-EPSPs are not significantly different from wild-type. Membrane potential and input resistance of the muscles is also indistinguishable from wild-type. (Data from electrophysiological recordings made from muscle 6 in segment A3 of wandering 3rd instar larvae). The overall numbers of boutons and the numbers of boutons per muscle surface area in CaMKIIT287D.Scer\UAS larvae carrying Scer\GAL4Mhc.PW or Scer\GAL4elav.PLu are not significantly different from wild-type. (Data from neuromuscular junctions of muscles 6 and 7 in segment A3 of wandering 3rd instar larvae). The overall structure of these bouton, the subsynaptic reticulum structure and the number of clear synaptic vesicles appear to be qualitatively wild-type.
Synaptic structure at the larval neuromuscular junction is dramatically altered in flies expressing CaMKIIT287D.Scer\UAS under the control of Scer\GAL4unspecified at both pre- and postsynaptic sites. The neuromuscular junctions have enlarged synaptic boutons and the distribution pattern of these boutons over the muscle cells is abnormal; the boutons are conglomerated in a smaller area than in wild type and the beaded appearance of the junction which is seen in wild-type larvae is less evident. There is a reduction in the subsynaptic reticulum and an increase in the number of active zones.
Flies expressing CaMKIIT287D.Scer\UAS under the control of Scer\GAL4c362 have an increased reflex response compared to wild-type flies in an assay in which the resistance response from the tibial extensor motor neurons in response to flexing the femorotibial joint is measured. Habituation of this reflex response is blocked in flies expressing CaMKIIT287D.Scer\UAS under the control of Scer\GAL4c362. The axon projections of the femoral chordotonal organ sensory neurons are normal in flies expressing CaMKIIT287D.Scer\UAS under the control of Scer\GAL4c362.