A 2403bp deletion resulting from the imprecise excision of P{EP}GE30561 removes the first exon of α-Cat, including the translation start site, and much of the intergenic region between α-Cat and CG32230. (Reported R4 coordinates converted to R5)
Imprecise excision of P{EP}GE30561 removes a 2403bp region between the insertion site and the α-Cat. This deletes the first exon of α-Cat, including the translation start site and much of the intergenic region between α-Cat and the predicted gene CG32230.
α-Cat1 mutant embryos show anterior cuticle defects and frequently display holes, some also develop a completely dorsal open phenotype or dorsal holes. The mutant embryos have similar number of amnioserosa cells at the onset of dorsal closure but show an increase in the number of delamination events, this however has no effect on the velocity of progression of the leading edge during the dorsal closure.
α-Cat1 mutant follicular epithelium cells lose cell-cell contacts and adopt a flattened, rounded shape, with loss of adherens junction markers. Border cells fail to migrate and remain at the anterior tip of the follicle.
The cuticle of α-Cat1 mutant embryos shows severe defects in the head skeleton, which result from a failure in head involution. The failure of head involution leaves a large anterior opening in the epidermis through which internal organs are expelled, and the epidermis/cuticle shrinks as a result of muscle contractions. About 68% of embryos display strong head defects and 32% show weak head defects. The ventral and dorsal cuticle appear normal and no obvious defects are observed in other embryonic tissues.
Ultrastructural morphology of epithelial adherens junctions is normal in stage 16 α-Cat1.
α-Cat1 mutant clones (generated through recombination of the α-CatUbi.PS rescue construct) do not develop in third instar larval imaginal discs.
α-Cat1 mutant clones in the ovary (generated through recombination of the α-CatUbi.PS rescue construct) display a variety of oogenesis defects. These include a compromised follicular epithelium leading to fused follicles and failure of border cell migration. The majority of α-Cat1 mutant cells have lost contact with wild type follicle cells. These cells rarely form multilayered clusters, but are usually flattened and tightly attached to the basement membrane. α-Cat1 mutant follicle cells appear to maintain apical-basal polarity, however neighbouring cells appear to lose polarity as their microvillus tufts point in different directions.
The severity of the embryonic cuticle defects characteristic for α-Cat1 mutants is further enhanced by combination with Df(1)Vinc2 or by expression of sqhDD.Scer\UAS under the control of Scer\GAL4c381 in the mutant background.
One copy of shgg119 causes a significant enhancement of the cuticle defects seen in α-Cat1 mutant embryos. >99% of embryos display a strong head defect and 21% show defects in the ventral cuticle.
One copy of Arpc1Q25st partially suppresses the cuticle defects seen in α-Cat1 mutant embryos. The phenotype is more severe when Arpc1Q25st is introduced maternally rather than paternally.
One copy of Arp3EP3640 partially suppresses the cuticle defects seen in α-Cat1 mutant embryos. Embryos show less severe defects on average and a fraction of embryos have normal heads.
One copy of SCARΔ37 partially suppresses the cuticle defects seen in α-Cat1 mutant embryos. Embryos show less severe defects on average and a fraction of embryos have normal heads. The phenotype is more severe when SCARΔ37 is introduced maternally rather than paternally.
Expression of shgScer\UAS.P\T.cSa under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU fails to rescue the embryonic lethality seen in α-Cat1 mutants.
Expressing α-Cat::shgScer\UAS.P\T.cSa allows α-Cat1 mutant clones (generated through recombination of the α-CatUbi.PS rescue construct) to develop in third instar larval imaginal discs. The follicle epithelium and border cell migration defects are also rescued.
Expressing shgScer\UAS.P\T.cSa does not allow α-Cat1 mutant clones (generated through recombination of the α-CatUbi.PS rescue construct) to develop in third instar larval imaginal discs. Mutant clone cells generated in the follicle epithelium lose cell contacts and border cells fail to migrate.
Expression of α-Cat::shgScer\UAS.P\T.cSa under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU rescues head morphogenesis and embryonic lethality in 89% of α-Cat1 mutants, but animals die during the larval stages.
Expression of Mmus\Ctnna2Scer\UAS.P\T.cDa under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU suppresses the follicular epithelium cell phenotypes seen in α-Cat1 mutant follicle cell clones (generated through recombination of the α-CatUbi.PS rescue construct). The border cell migration defects are partially rescued.
Ubiquitous expression of Mmus\Ctnna2Scer\UAS.P\T.cDa under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU rescues the head involution defects seen in α-Cat1 mutant embryos. Animals are unable to develop beyond the pupal stages.
Expression of Mmus\Ctnna1Scer\UAS.P\T.cDa under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU partially suppresses the follicular epithelium cell phenotypes seen in α-Cat1 mutant follicle cell clones (generated through recombination of the α-CatUbi.PS rescue construct). The border cell migration defects are not rescued.
Ubiquitous expression of Mmus\Ctnna1Scer\UAS.P\T.cDa under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU fails to rescue the head involution defects seen in α-Cat1 mutant embryos. Animals are unable to live beyond the embryonic stages.
Expression of Mmus\Ctnna2Δ56.Scer\UAS.P\T under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU fails to suppress the follicular epithelium cell phenotypes seen in α-Cat1 mutant follicle cell clones (generated through recombination of the α-CatUbi.PS rescue construct). The border cell migration defects are not rescued.
Ubiquitous expression of Mmus\Ctnna2Δ56.Scer\UAS.P\T under the control of Scer\GAL4da.G32 and Scer\GAL4Act.PU partially rescues the head involution defects seen in α-Cat1 mutant embryos. Some animals are able to develop to the larval stages.
