Early consolidation of development and physiology of an identified presynaptic nerve terminal

BACKGROUND: A central objective in the field of neurobiology is to understand the developmental plasticity of neurons. The pursuit of this objective has revealed the presence of critical periods in neural development. Here, critical periods are defined as developmental time windows during which neural remodeling can take place; outside of these times neural plasticity is reduced. We have taken advantage of transgenic technology at the Drosophila melanogaster neuromuscular junction (NMJ) to investigate developmental plasticity and critical period determination of an identifiable nerve terminal. RESULTS: Using temperature-dependent Gal80 control of transgene expression, we regulated the expression of dNSF2(E/Q), a dominant-negative version of the Drosophila NSF2 gene, by shifting developing embryos and larvae between permissive and restrictive temperatures. dNSF2(E/Q) reduces synaptic strength and causes tremendous overgrowth of the neuromuscular junctions. We therefore measured synaptic transmission and synaptic morphology in two temperature-shift paradigms. Our data show that both physiological and morphological development is susceptible to dNSF2(E/Q) perturbation within the first two days. CONCLUSION: Our data support the view that individual motor neurons in Drosophila larvae possess a critical window for synapse development in the first one to two days of life and that the time period for morphological and physiological plasticity are not identical. These studies open the door to further molecular genetic analysis of critical periods of synaptic development.