Polytene chromosomes normal.
Amino acid replacement: I578T.
Substitution of an isoleucine for a threonine in EGF-repeat number 14.
A missense mutation in the extracellular EGF-like domain.
ommatidium & eye disc | male
photoreceptor cell & eye disc | male
photoreceptor cell R8 & eye disc | male
The wing blistering phenotype seen in the posterior compartment of wings in flies expressing EogtGD5084 under the control of Scer\GAL4en.PU in the presence of Dcr-2Scer\UAS.cDa is dominantly partially suppressed if the flies are also heterozygous for Nspl-1.
The severe reduced eye found in Nspl-1/Y; E(spl)1/+ mutants is partially suppressed upon overexpression of E(spl)123-179.CtD.Scer\UAS immediately anterior to the morphogenetic furrow under the control of Scer\GAL4h-H10. Expression of E(spl)123-179.CtD.Scer\UAS not only increases eye size (facet numbers), but also restores the patterning of the facets. This patterning is, however, lost toward the anterior margin of the residual eye.
Expression of E(spl)123-179.CtD.Scer\UAS in trans, in all cells posterior to the morphogenetic furrow, under the control of Scer\GAL4GMR.PF does not rescue the severe reduced eye phenotype found in Nspl-1/Y; E(spl)1/+ mutants. The absence of rescue is also supported by facet numbers, which upon expression of three independent E(spl)123-179.CtD.Scer\UAS lines closely mimicks control levels in Nspl-1/Y; E(spl)1/+ mutants. Rescue of the Nspl-1/Y; E(spl)1/+ retinal defects by E(spl)123-179.CtD.Scer\UAS therefore requires expression in a region of the developing eye where funding R8 photoreceptors are patterned and specified.
Df(3R)Espl22/+ or expression of CkIIαdsRNA.Scer\UAS mediated by Scer\GAL4h-H10 suppresses the Nspl-1/Y split/missing scutellar bristle phenotype but does not modulate the Nspl-1/Y ectopic scutellar bristle phenotype.
The addition of BacA\p35Scer\UAS.cHa driven by BacA\p35Scer\UAS.cHa to Nspl-1 somatic clones does not rescue all the eye phenotypes seen in Nspl-1 cells. When DlScer\UAS.cLa is driven by Scer\GAL4GMR.PF in a Nspl-1 background photoreceptor R8 differentiation is greatly reduced. The R8 photoreceptor cell phenotype seen in Nspl-1 clones is slightly enhanced by the addition of fng13.
The addition of E(spl)1.Scer\UAS driven by Scer\GAL4unspecified to a Nspl-1 background produces a strong enhancement of the Nspl-1 eye phenotype, whilst the addition of E(spl)Scer\UAS.cGa shows little or no effect.
Nipped-A222.3, Nipped-A394.2, l(2)41Ae7, Chie5.5, vg1 and Su(H)8 have little or no effect on the eye phenotype. Nipped-A222.3, Nipped-B292.1, Chie5.5, vg1, Su(H)16 and Su(H)8 have little or no effect on the bristle phenotype. Df(2R)Nipped-D341.1, Df(2R)Nipped-D263.3 and Df(2R)Nipped-E338 dominantly suppress the eye phenotype. Df(2R)Nipped-D341.1, Df(2R)Nipped-D263.3, Df(2R)Nipped-E43 and Df(2R)Nipped-E338 dominantly enhance the bristle phenotype.
The heterozygous eye phenotype is unaffected if the flies are also carrying two copies of E(spl)tLa, but is enhanced if the flies are carrying two copies of E(spl)K:CAACdel or E(spl)K1K2mut; resulting in ommatidial fusion and bristle multiplication.
The number of thoracic bristles is increased further in hemizygous or Df(3R)Dl-FX3 ; Nspl-1 double heterozygous flies, and the number of bristles is restored to wild-type in Nspl-1; wgS107 double heterozygotes.
Double mutants with cnomis1 always have rumpled wings curved downwards and extra bristles.
Nspl-1 flies also heterozygous for E(spl)1 show a conspicuous enhancement of this phenotype; in particular the size of the compound eye is severely reduced and only 15-30 widely spaced facets can be distinguished. The ommatidia contain fewer photoreceptors than normal, and the rhabdomeres are often distorted. A large number of secondary pigment cells fill the space between the scattered photoreceptor cell clusters. Photoreceptor cell axons follow an aberrant course, and usually fail to enter the eye stalk. The pattern of cell proliferation is qualitatively normal in Nspl-1/Y E(spl)1/+ flies as assayed by BrdU incorporation. There is abundant cell death in the eye imaginal discs of these flies during the third instar larval stage, dead cells are more abundant behind the morphogenetic furrow.
Both the eye and bristle phenotype are suppressed when in combination with one copy of mam10 or mam88-4, weak suppression is seen with mam88-10. Hemizygotes and homozygotes, in combination with one copy of groE73, display an Ax-like phenotype, small gaps in the posterior end of the fifth longitudinal wing vein.