An average of 4.5% osupd-4, sqhAX3 homozygous mutant embryos show germ-band extension defects, much reduced compared to osupd-4 homozygous mutant embryos. Ectopic apical cell constriction defects are rescued in osupd-4, sqhAX3 homozygous mutant embryos.
The multiple wing hair phenotype caused by expression of towScer\UAS.cCa under the control of Scer\GAL4hs.PB using heat shock at 24 hours after puparium formation is enhanced if the flies are also carrying one copy of sqhAX3.
Homozygous lethality is fully rescued by sqhA20.T:Zzzz\FLAG, partially rescued by sqhE21.T:Zzzz\FLAG (sqhAX3 animals carrying sqhE21.T:Zzzz\FLAG survive to the late pupal stage) and by sqhA21.T:Zzzz\FLAG (sqhAX3 animals carrying sqhA21.T:Zzzz\FLAG survive to the early pupal stage), and not rescued by sqhA20.A21.T:Zzzz\FLAG (sqhAX3 animals carrying sqhA20.A21.T:Zzzz\FLAG die as first instar larvae). Homozygous female germline clones expressing sqhA20.A21.T:Zzzz\FLAG have phenotypes nearly indistinguishable from homozygous female germline clones that do not carry sqhA20.A21.T:Zzzz\FLAG. The morphology of egg chambers derived from homozygous female germline clones expressing sqhA21.T:Zzzz\FLAG is grossly normal, with a well-differentiated oocyte and accompanying nurse cells. However, 73% of egg chambers contain at least one binuclear cell, and 80% contain less than 15 nurse cells. Substantial nurse cell cytoplasm remains untransferred even by stage 13 in many egg chambers. These clones produce some eggs. Approximately 23% of eggs laid by females carrying homozygous germline clones expressing sqhA21.T:Zzzz\FLAG and fertilised by males homozygous for a sqh+ transgene begin development, but they do not hatch. Nuclear migration in these eggs is often isotropic, producing a spherical cloud of nuclei. Approximately 80% of egg chambers derived from homozygous female germline clones expressing sqhE21.T:Zzzz\FLAG appear wild-type. 15% contain fewer than 15 nurse cells, and only 9% contain any binuclear cells. Stage 13 egg chambers containing significant amounts of nurse cell cytoplasm are relatively common, although 80% of eggs are wild-type in length. Approximately 60% of eggs laid by females carrying homozygous germline clones expressing sqhE21.T:Zzzz\FLAG and fertilised by males homozygous for a sqh+ transgene begin development, and 41% of these embryos hatch. 46% of these larvae reach adulthood.