1 day old Scer\GAL4loco.PU>swsGD3277 flies do not show defects in the lamina cortex compared to controls, but at 14 days old have vacuoles in the lamina cortex; at 30 days old the entire lamina cortex is filled with vacuoles and additional lesions form near the first optic chiasm (age-dependent degeneration). 14 day old Scer\GAL4repo.PU>swsGD3277 flies have vacuoles in the lamina cortex.
Small membranous glial structures can be seen in lamina cortex of 2 day old Scer\GAL4loco.PU>swsGD3277 flies, becoming larger, multilayered and more prominent in 14 day old flies; the same glial whorls can be detected in 14 day old Scer\GAL4repo.PU>swsGD3277 flies.
Scer\GAL4repo.PU>swsGD3277 flies have significantly fewer glial cells in the optic lobe compared to controls at two days old, and even more significantly at 14 days old; epithelial glia in the lamina neuropil are also significantly decreased compared to age-matched controls (2 and 14 days old) but there is no significant difference in glial cell loss between 2 and 14 day old knockdown flies. At least some of glial cells show signs of apoptosis (at 7 days old).
Expression of swsGD3277 driven by Scer\GAL4alrm.PD (targeting astrocyte-like neuropil glia) or Scer\GAL4Akap200-NP2222 (targeting cortex glia associated with neuronal cell bodies) does not cause significant defects in brains of 14 day old flies. swsGD3277 knockdown using Scer\GAL4Mz709 (targeting ensheathing and subperineurial glia) or even more so Scer\GAL4Gli-rL82.29 (targeting subperineurial glia) results in vacuolization of the lamina cortex of 14 day old flies. Small membranous glial structures are seen in the lamina cortex of Scer\GAL4Gli-rL82.29>swsGD3277 (and less so, Scer\GAL4Mz709>swsGD3277) flies. Overall, GAL4 knockdown patterns suggest phenotypes are likely due to loss of sws in the subperineurial pseudocartridge glial cells.
Expression of swsGD3277 driven by Scer\GAL4Mz709 leads to glia with stunted processes, leading to loss of glial ensheathment of neuronal cell bodies and neurites in the medulla and lobula of 14 day old adult brains, along with gaps between neurites. 1 day old Scer\GAL4repo.PU>swsGD3277 flies also show stunted glial processes and gaps between neurites (becoming more prominent in 14 day old flies, with almost all neurites surrounded by empty space). Scer\GAL4alrm.PD>swsGD3277 flies (14 day old) do not show these phenotypes. Scer\GAL4Appl.G1a>swsGD3277 flies (1 or 14 day old) do not show glial hyper-wrapping phenotypes.
Expression of swsGD3277 driven by Scer\GAL4repo.PU or Scer\GAL4loco.PU significantly reduces performance in a fast phototaxis assay (measuring percentage transitions towards light) in 2 day old flies compared to controls; this phenotype is progressive, with performance in 14 day old flies worse than in 2 day old flies. Performance is also significantly reduced when expression of swsGD3277 is driven by Scer\GAL4Gli-rL82.29, Scer\GAL4Mz709 or Scer\GAL4alrm.PD in 14 day old flies.
Adults expressing swsGD3277 under the control of Scer\GAL4elav.PLu (in the presence of Dcr-2Scer\UAS.cDa to increase the efficiency of RNAi) do not show a significant defect in avoidance of noxious temperature (46[o]C) compared to control flies.