Electroretinograms of ninaE7 mutants do not show the expected prolonged depolarization afterpotential to blue light stimuli normally observed in controls.
ninaE7 mutant adult males have reduced ability to orient towards and remain close to a female, compared to controls; they also lose the bias seen in controls to extend the wing closest to, rather than furthest from, the female; following of females, wing extensions and copulation are significantly reduced, compared to controls.
Mutant larvae show strong discrimination between 18[o]C and 24[o]C in a binary choice thermotaxis assay (as do wild-type controls), but discrimination between 18[o]C and either 20 or 22[o]C is eliminated in the mutant larvae.
Individuals develop reasonably normal rhabdomeres and none show membrane curtains.
Reduction in the photopigment content and a similar reduction in sensitivity to light. At maximal excitation intensity the calcium signal has a similar wave form to wild type photoreceptors. A partial recovery of sensitivity of the calcium signal to a second light flask is observed.
Degeneration of photoreceptors but light-dependent 35S-labelled guanosine 5'-3-0-(thio)triphosphate (35S GTPγS) binding is normal.
More rapid rate of R1-6 photoreceptor degeneration than ninaE5, but less rapid than ninaE8.
0.08% of wild-type levels of functional rhodopsin.
Retains regular rhabdomeric membranes.
Rhabdomeres of young flies are reduced in size and show aberrant packing of microvilli. Rhabdomeres are nearly wild type in adults.
The electroretinogram (ERG) of homozygous flies is abnormal; they display neither inactivation nor afterpotential, and the on-transient component is absent. Heterozygotes have an intermediate phenotype that varies somewhat with age. Homozygotes have almost no rhodopsin, heterozygotes have approximately 37% rhodopsin compared to wild-type levels. The R1-R6 rhabdomeres have normal morphology in homozygotes, although they are sightly reduced in volume.