UAS regulatory sequences drive expression of Syt1 carrying the D362A mutation, resulting in a dominant-negative protein. This mutation is in a conserved calcium binding residue and corresponds to the D307A mutation seen in the orthologous human SYT2 gene in a family with a neuromuscular junction disorder resembling Lambert-Eaton myasthenic syndrome. The protein is tagged with Tag:MYC.
A2785672C
D362A | Syt1-PA; D360A | Syt1-PB; D360A | Syt1-PC; D360A | Syt1-PE; D361A | Syt1-PH; D360A | Syt1-PI
D362A
Analogous mutation in human SYT2 implicated in congenital myasthenic syndrome 7, presynaptic; mutation carried on in vitro construct; site of nucleotide substitution in fly gene and specific disease association inferred by FlyBase curator.
Third instar larvae expressing Syt1D362A.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4elav-C155 (and in the presence of endogenous Syt1) show neurotransmission defects at neuromuscular junctions: severely reduced excitatory junctional current amplitude (recorded in both 0.2 mM and 2 mM external Ca[2+]), increased frequency of miniature excitatory junction currents and increased facilitation of evoked release upon high-frequency stimulation.
Scer\GAL4elav-C155/Syt1D362A.UAS.Tag:MYC fails to rescue Syt1unspecified
The neurotransmission defects at neuromuscular junctions in (they fail to support calcium-triggered neurotransmitter release: flat excitatory postsynaptic current, recorded in 2 mM external Ca[2+] with zero amplitude, reduced cumulative vesicle release (defined by charge transfer), high frequency of miniature excitatory junction currents) characteristic for Syt1unspecified mutant third instar larvae cannot be rescued by Scer\GAL4elav-C155-driven expression of Syt1D362A.Scer\UAS.T:Hsap\MYC in the mutant background.
