In the temperature sensitive combination Egfrtop-CA/Egfrf7 the pleura expands at the expense of the sternites and tergites.
All RP2 and RP2sib neurons are missing.
At 25oC, approximately 90% of embryos fail to undergo head involution. Development of the cuticle and central nervous system and germband retraction are also abnormal. At 28oC, homozygous embryos have a "faint little ball" phenotype with poor cuticle formation.
Mutant embryos show absence of dorsal trunk and reduced visceral branches. Dorsal branch and lateral trunks are normal. The dorsal trunk is rescued in a put135 mutant background.
25-49% of Egfrtop-CA/Egfrf7 flies survive to adulthood (FBrf0049928). The anterior dorsal, posterior dorsal, ventral and spiracular histoblast nests contain fewer cells than in wild-type pupae 6 hours after pupariation. The dorsal histoblast nests remain separate 24 hours after pupariation, in contrast to wild-type where they are fused. The histoblast nests in the anterior segments are less abnormal than those in posterior segments. Adults sometimes have holes in the abdominal cuticle and lack spiracles in the abdominal segments. In less severely affected adults chaetae appear abnormal and the distribution of hairs on the tergite, sternite and pleura is irregular and sparse. The thickness of the cuticle is reduced and spiracles are abnormal.
Homozygotes show a severe embryonic lethal phenotype at 29oC and a weak embryonic lethal phenotype at 18oC. Enhances the female sterility and adult morphological defects of Egfrt1. Rarely survives as transheterozygote with the semi-viable Egfrtop-CA allele.
At 29oC Malpighian tubules in homozygous embryos exhibit a very reduced number of cells. Numbers are close to those of wild type when raised at 18oC. Temperature shift experiments reveal Egfr is required for normal tubule development from 3.25 hours AEL until after 8 hours AEL.
Homozygotes and hemizygotes display a weak 'flb' phenotype. Embryos produced from heteroallelic combination with Egfrt1 have a severe ventralised phenotype, reduction in size of their dorsal appendage.
Weak lethal phenotype: embryos lack some head and telson structures and have some development of the ventral cuticle.