embryos show normal development until stage 14. After this stage, spoZ339
embryos exhibit head involution failure, an absence of midgut and dorsal closure, an abnormal hindgut looping and a lack of cuticle differentiation. These defects are seen at the same level in embryos from spoZ339
germline clones and zygotic mutants, indicating that there is no spoZ339
embryos rarely hatch. When an artificial pulse of 20E is delivered to these embryos midway through embryogenesis, approximately 30% survive to hatch and 20% survive to adulthood. Rescued spoZ339
females produce no progeny due to arrest of egg development at stage 8 of oogenesis, while rescued males are fertile.
An artificial pulse of E allows 25% of spoZ339
embryos to hatch and 12% to become adults. A pulse of ketotriol allows 13% to hatch but only 1% survive to become adults. In contrast, pulses of ketodiol and 7dC do not rescue the lethality of spoZ339
embryos at all.