Amino acid mutation that bridges the ligand binding and pore domains and is thought to be important for channel gating in vertebrate nicotinic acetylcholine receptors.
Amino acid replacement: K46E.
A19342938G
K103E | nAChRalpha7-PA; K103E | nAChRalpha7-PD; K103E | nAChRalpha7-PE; K103E | nAChRalpha7-PF
K46E
The reported amino acid location of the K to E mutation does not match the reference sequence. This is in part due to the use of a downstream translation start in FBrf0191369. The mutation was reported in the context of a string of 3 amino acids (EKN, GAAAAGAAT) and this matches the annotated site of the mutation.
gfA1 flies have a defect in the jump circuit between the peripherally synapsing interneuron (PSI) branch of the giant fiber and the dorsal lateral muscle (DLM) motor neuron. This is demonstrated by intracellular recordings of DLMs following giant fiber stimulation; while the DLMs of wild-type flies can follow stimulation frequencies of up to 100 Hz, gfA1 DLMS only respond to giant fiber stimulation at very low frequencies. This phenotype can also be seen in gfA1/gfAPΔEY6 and gfA1/gfAPΔ5 transheterozygotes.
gfA1/+ flies almost always fail to jump in visual jump assays where control flies jump 70% of the time.
The excitatory postsynaptic potential (EPSP) generated by the MN5 neurons in response to 1 Hz giant fiber stimulation is significantly smaller in gfA1 flies than in wild-type flies. However, although the EPSP is smaller, it is always generated without failure and does not show significant changes in shape or jitter in comparison to that generated by wild type.
The latency of the response of the dorsal longitudinal muscle a (DLMa) following brain stimulation is much longer than in wild-type flies.
Thomas.
Abnormal DLM response is due to a defect in the GF output to PSI or PSI itself.