stj1 mutant photoreceptor terminals show increased accumulation of autophagic vacuoles compared to controls.
Flies with homozygous visual systems (made using the eyFLP method) show a reduced depolarisation in response to light stimulus and a lack of "on-off" transients in electroretinogram recordings. Six photoreceptor terminals are seen per lamina cartridge in the flies, as occurs in wild type.
Flies in which homozygous clones have been induced in the presynaptic photoreceptors only (made using the ey3.5FLP system) show a lack on "on" transients in electroretinogram recordings.
stj1/Df(2R)Exel7128 animals generally arrest as pupae, with some animals emerging as uncoordinated adults.
stj1/Df(2R)Exel7128 mutants show seizure-like activity when recordings are taken from muscles 6/7 of dissected third instar larvae with intact ventral nerve cords at elevated temperature (36[o]C); although burst events are relatively rare, activity trains often last 30 seconds or longer. The mutant bursts are lower in amplitude than those of controls.
Evoked excitatory junctional potentials (EJPs) at the third instar larval neuromuscular junction have a reduced amplitude compared to controls in stj1/stj2, stj1/stj3 and stj1/Df(2R)Exel7128 animals. Ca[2+] cooperativity does not appear to be affected at stj1/Df(2R)Exel7128 synapses, but there is a reduction in synaptic Ca[2+] sensitivity, and the mutant synapses show increased facilitation compared with controls.
The amplitude of EJPs at the neuromuscular junction is normal in stj1/+ third instar larvae.
The mean amplitude, distribution of amplitude and frequency of spontaneous miniature EJPs at the larval neuromuscular junction are normal in stj1/Df(2R)Exel7128 animals.
Neuromuscular junctions of stj1/Df(2R)Exel7128 third instar larvae show an increase in synapse length/muscle area and an increase in bouton number/muscle area compared to controls. Ultrastructural analysis of individual boutons shows that there is no difference in vesicle density, number of active-zone associated vesicles or vesicle size in the mutants compared to controls.