Approximately 25% of homozygotes (lacking zygotic Patj function) do not hatch, approximately 25% die in early larval stages and the rest die as early pupae (metamorphosis is not initiated). Homozygous embryos derived from females containing homozygous germline clones (lacking maternal and zygotic Patj function) show nearly the same pattern of lethality as embryos lacking zygotic Patj function, but show an increased lethality in third instar larvae at the expense of dead pupae. Embryos derived from females containing homozygous germline clones mated to wild-type males develop until adulthood.
46% of homozygous embryos that die during embryogenesis have a normal cuticle, more than 30% fail to develop any cuticle and 18% have strong cuticle defects, showing a general shortening of the cuticle and head defects, while segmentation appears normal. Approximately 15% of homozygous embryos that die during embryogenesis fail to retract the germband correctly.
Homozygous follicle cell clones do not show loss of polarity or multilayering of tissue.
PatjΔ1 has lethal phenotype, suppressible | partially by sqhUASp.EGFP/Scer\GAL4arm.PS
PatjΔ1 has lethal phenotype, non-suppressible by Scer\GAL4arm.PS/sqhAA.UASp.EGFP
PatjΔ1, shg[+]/shgR69 has increased cell death | embryonic stage phenotype
PatjΔ1 has embryonic/first instar larval cuticle phenotype, enhanceable by shg[+]/shgR69
PatjΔ1 has embryonic/first instar larval cuticle phenotype, suppressible | partially by MbsT541/Mbs[+]
PatjΔ1 has embryonic/first instar larval cuticle phenotype, suppressible | partially by sqhUASp.EGFP/Scer\GAL4arm.PS
PatjΔ1, shg[+]/shgR69 has embryonic epidermis phenotype
shgR69/+ enhances the lethality of PatjΔ1 homozygotes, with greater lethality at earlier stages. The frequency of cuticle defects seen in PatjΔ1 embryos is also enhanced by shgR69/+. Late-stage shgR69/+ ; PatjΔ1/PatjΔ1 embryos have a multilayered epidermis, many of the epidermal cells start to round up and many epidermal cells undergo apoptosis.
MbsT541/+ reduces the frequency of embryonic lethality in PatjΔ1 homozygotes from 28 to 12%. In addition, the cuticle defects seen in PatjΔ1 embryos are strongly decreased in frequency in the MbsT541/+ background. PatjΔ1/MbsT541 PatjΔ1 pupae start metamorphosis (reflected by elongation and remodelling of the wing disc).
Expression of sqhScer\UAS.P\T.T:Avic\GFP-EGFP under the control of Scer\GAL4arm.PS decreases the frequency of embryonic lethality and also decreases embryonic cuticle defects in PatjΔ1 homozygotes.
Expression of sqhAA.Scer\UAS.P\T.T:Avic\GFP-EGFP under the control of Scer\GAL4arm.PS does not the affect the lethality seen in PatjΔ1 homozygotes.