dlg1² homozygosity leads to the formation of large tumors in the third instar larval wing disc.

dlg1² mutant larvae do not display neuroblast overproliferation.

Delamination and migration of border follicle cells are both accelerated in dlg1² heterozygotes. In dlg1²/dlg1⁵ flies the border follicle cells have much reduced polarity. Delamination of these cells is delayed, but their migration is accelerated.

dlg1²/dlg1⁵ animals are viable and have completely normal egg chambers at 18^oC. After 6 hours at 25^oC, follicle cells exit the follicular epithelium and intermingle with germ cells at the anterior and posterior poles of the egg chamber. Cells that remain in the epithelium retain their polarised characteristics, whereas those that have exited the epithelium have an apolar morphology. Nurse cells extend processes to meet the invasive follicle cells. Follicle cells at the anterior and posterior ends of the egg chambers preferentially incorporate BrdU. Follicle cells also have an invasive phenotype in homozygous dlg1² females shifted to 25^oC. Follicle cells also an invasive phenotype in dlg1²/dlg1¹⁸ females. Nurse cells extend processes to meet the invasive follicle cells. Border cells migrate in advance of the follicular epithelium in dlg1^sw/dlg1² egg chambers.

Temperature-sensitive allele. At the permissive temperature (18^oC), hemizygotes show a hypomorphic phenotype, developing small imaginal disc tumours. Type I boutons appear similar to wild-type in these animals. At the restrictive temperature (29^oC), hemizygotes show a similar phenotype to dlg1⁶ or dlg1¹⁴ hemizygotes, developing large tumours in the brain and imaginal discs. The subsynaptic reticulum at type I boutons is poorly developed in these animals. Hemizygotes shifted to the restrictive temperature during embryogenesis usually die before the wandering third larval instar stage, and 85% of surviving larvae show a mutant phenotype at third instar type I boutons, indicating that dlg1 function is required during embryogenesis. There is a second temperature-sensitive period during the mid second/third larval instar stage.

Embryos exhibit defects associated with dorsal closure and head involution.

Completely lethal at 25^oC, homozygotes show 75% viability at 18^oC. Females exhibit a maternal-effect embryonic lethality when fertilised by dlg1² sperm even at the permissive temperature. This lethality can be rescued by wild-type sperm.

Homozygotes fail to survive when raised at 25^oC; when raised at 18^oC however, 37% survival attained; hemizygous females show 65-70% survival at 18^oC, but are also lethal at 25^oC. Survival at 18^oC nearly complete in heterozygotes with dlg1⁵ and dlg1¹⁸ and survival at 25^oC is 4% and 95% respectively. Embryos produced by matings between surviving dlg1² flies raised at 18^oC show but 4% hatchability at 18^oC and such crosses are completely sterile at 25^oC; however in crosses of homozygous dlg1+2 females to dlg1⁺ males, rescue of heterozygous daughters nearly complete at either 18^oC or 25^oC and is somewhat reduced at 29^oC. Abnormal embryos produced by dlg1² females show failure of dorsal closure and head involution. The maternal-effect of dlg1 is germ-line specific, since embryos produced by homozygous clones in heterozygous mothers are indistinguishable from those produced by homozygous mothers (Perrimon, 1988). temperature-sensitive; 5.5 kb insert near 5' end

dlg1² has neoplasia | third instar larval stage phenotype, enhanceable by Scer\GAL4^en-e16E/ph-p^GD4480

dlg1² has neoplasia | third instar larval stage phenotype, enhanceable by Scer\GAL4^en-e16E/Su(z)2^KK103634

dlg1² has wing disc | third instar larval stage phenotype, enhanceable by Scer\GAL4^en-e16E/ph-p^GD4480

dlg1² has wing disc | third instar larval stage phenotype, enhanceable by Scer\GAL4^en-e16E/Su(z)2^KK103634

dlg1² has wing disc | third instar larval stage phenotype, suppressible by Scer\GAL4^en-e16E/Socs36E^UASp.cCa

dlg1² has phenotype, suppressible by Scer\GAL4^da.G32/Rnor\Dlg1^UAS.cTa