The epidermis of arm8 mutant embryos lacks the wide expanse of naked cuticle separating the denticle belts. Most of these embryos fail to hatch.
arm8 embryos show normal dorsal closure. arm8/+ eyes are normal in appearance.
arm8 somatic stem cell (SSC) clones in the ovary are lost slightly more rapidly than wild-type clones, but are lost at a slower rate than arm2 clones. arm8 follicle cell clones have normal morphology compared to neighbouring wild-type follicle cells.
arm2 has no dramatic effect on germline stem cell (GSC) maintenance in the ovary; approximately 60% of mutant GSCs observed in ovaries during the first week after clone induction are maintained for two more weeks (compared to 70% for controls).
Mutant embryos have segment polarity defects, although head involution and dorsal closure are normal.
arm8 embryos show a similar tracheal branching phenotype to arm4 embryos.
Homozygous clones in the wing show no disturbance in planar polarity.
Homozygous clones in eyes show normal ommatidial polarity.
arm8 embryos derived from homozygous female germ line clones (lacking both zygotic and maternal arm function) lack RP2 neurons. They show a broad array of central nervous system defects, including gaps in the longitudinals and poorly formed commissures.
Embryos incubated at the restrictive temperature after acridine orange injection show increased cell death in a similar pattern to that seen for wgl-12 embryos shifted at stage 11. Cell death in the rest of the segment is similar to wild type.
Homozygous clones in the eye are extremely small and only infrequently observed.
Temperature-sensitive allele. Homozygous clones are recovered at reasonable frequency in the wing pouch of discs shifted to the restrictive temperature 18 hours before the end of the third larval instar stage, but not in discs shifted to the restrictive temperature 48 hours before the end of the third larval instar stage. Homozygous clones are produced in the part of the disc that gives rise to the dorsal thorax under both conditions.
Embryos that are zygotically and maternally mutant for arm8 have a very strong segment polarity phenotype, and secrete only denticles with no naked cuticle. Embryos that are zygotically and maternally mutant for arm8 and are expressing armS10.Scer\UAS.T:Hsap\MYC (using Scer\GAL4e22c) essentially secrete only naked cuticle.
Embryos exhibit severe segment polarity defects.
Dorsal tracheal trunks exhibit irregular width and the connections between lateral trunks is incomplete.
When arm8; armBCD7/+ flies are shifted to 25oC during the third larval instar the resulting adults have missing pattern elements along the wing margin and alula. The abdomens lack sternites.
Embryos lacking both maternal and zygotic sgg and arm function have an embryonic cuticle phenotype like that of arm mutant embryos alone. Embryos lacking maternal sgg and arm but receiving wild type paternal copies develop into normal embryos that survive until adulthood. Embryos lacking maternal sgg and arm but receiving a wild type paternal copy of arm+ only, show a sgg naked cuticle phenotype.
Clonal analysis reveals that oogenesis is normal, including with respect to cytoplasmic actin distribution, but reduction in maternal contribution enhances the embryonic phenotype. Eggs derived from mutant germlines are laid, and have normal anterior-posterior and dorso-ventral patterning.
Very strong segment polarity phenotype. Homozygous clones survive at a higher frequency in the dorsal regions of the leg disc, this biased distribution is produced by differential survival, not directed migration.
Late third instar larvae have very small imaginal discs, pupae die without differentiating any adult cuticle.