Wing disc clones of the temperature-sensitive sec5^ts1 mutant allele (generated in the posterior compartment using UAS-flp under the control of Scer\GAL4^en-e16E) do not survive when they are induced in flies that are shifted to the restrictive temperature (30[o]C) for 48 hours during the early third instar larval stage. These discs are referred to as "ablated discs". The resulting adult wings are normal in size and there is no significant developmental delay. For the first 6 hours after the temperature upshift (AUS) the ablated discs are similar in size to controls. However by 12 hours AUS both the posterior and anterior compartments of the ablated discs are significantly smaller. At 36 hours the ablated and control discs are again similar in size. Apoptosis is detected as early as 6 hours AUS, with the amount peaking at 12 hours. At 12 hours AUS the ablated discs have a greater density of mitotic cells than controls. At 24 hours AUS, ablated and control discs show roughly the same density of mitotic cells. By 36-40 hours the number of mitotic cells remains high in mutant discs, but falls in controls.

sec5^ts1 mutant posterior compartment eye disc clones (generated using the eyFLP method under the control of Scer\GAL4^en-e16E) do not survive when they are induced in flies that are reared at the permissive temperature (18[o]C), and shifted to the restrictive temperature (30[o]C) for 48 hours during the early third instar larval stage. The resulting adult eyes are normally sized and patterned.

Adults in which eye tissue has been made homozygous for sec5^ts1 during development (using the EGUF method) show complete eye ablation at 25 and 29[o]C but have a full eye, similar to controls, at 18[o]C. The photoreceptors are short in homozygous eyes at 18[o]C, while at 15[o]C they are of normal size.

Homozygous larvae raised at 15[o]C do not survive past the first instar.

Females carrying homozygous germline clones lay few eggs at 25 and 18[o]C. At 15[o]C, they lay some fertilised eggs (although still far fewer than those laid by wild-type females). Development of these embryos prior to cellularisation appears normal, but they are severely defective during cellularisation (this phenotype cannot be rescued by a wild-type paternal copy of sec5). The mutant embryos do not enter phase II of cellularisation; furrows rarely descend between nuclei and the nuclei do not elongate. At a time when wild-type embryos have mostly advanced to phase III or IV of cellularisation at 15[o]C, the nuclei still appear round rather than elongated in the mutant embryos, and the furrows below the nuclei often appear fused. Some embryos begin gastrulation despite the absence of proper cellularisation; most regions of the gastrulating embryos are acellular, but some patches contain misshapen, disorganised cells. Actin is disordered in the mutant embryos during cellularisation and does not accumulate in furrow canals.