Germaria in hhAC/hhts2 flies exhibit an enlarged morphologic structure filled with fusome-containing cysts and are defective in correct segregation of individual germline cysts at region 2a/2b.
Mushroom body gamma neurons appear indistinguishable from controls in hhAC/hhts2 animals transferred to the restrictive temperature at the onset of pupariation and analysed at 29 hours after puparium formation.
hhAC heterozygotes do not exhibit an eye phenotype.
In hhAC first instar larvae, the epidermis consists only of type 4 cells, whereas in wild-type, hh is secreted from type 1 cells and forms a morphogen gradient that allows the differentiation of cells type 1 to 3 in a concentration-dependent manner, which affects the patterning of bristles on the cuticle.
Expression of hhSF.Scer\UAS.T:Rnor\CD2, under the control of Scer\GAL4Scer\FRT.Rnor\CD2.Act5C in hhAC mutants only rescues type 1 and adjacent type 2 cuticles, but not the distant type 3 cuticle, In addition, the type 2 cuticle domain is more restricted than it is in wild-type embryos.
Ectopic expression of hhC85S.Scer\UAS.cGa, under the control of Scer\GAL4en-e16E in hhAC first instar larvae induces only type-2 cuticle, and no type 3 cuticle.
The induction of hhAC mitotic clones in the labial discs by expression of Scer\FLP1Scer\UAS.cDa under the control of Scer\GAL4pb.PJ, in combination with the Minute technique, results in the deletion of some pseudotracheal cells along the A-P compartment boundary of the adult labium.
Homozygous hhAC mutants are zygotic lethal and exhibit strong cuticle phenotypes.
hhAC heterozygotes are not significantly different from wild-type. However, they are slightly dominant, with an eye that is about 10% smaller than wild-type.
hhbar3/hhAC mutants exhibit about six columns of ommatidia per eye compared to 28-30 columns in wild-type.
Homozygous mutant larvae lack a well differentiated head skeleton, cuticles completely covered by a lawn of denticles.
The areas of naked cuticle are replaced by denticles in the mutant embryos, resulting in a "lawn of denticles" without clear polarity.
The ventral cuticles of hhAC embryos are transformed into a lawn of row 5 type denticles (i.e.- no naked cuticle is formed).
Ovaries of hhAC/hhts2 females maintained at the restrictive temperature (29oC) for 4-5 days show a number of defects including multicyst egg chambers. Large groups of disorganised somatic cells are seen at the periphery of the germaria and multicyst egg chambers.
Neuroblast NB 7-3 is missing in 40% of mutant hemisegments.
hhts2/hhAC embryos have a severe segment polarity phenotype, in which the naked cuticle is lost, at the restrictive temperature.
Mutant embryos are short and show a "lawn of denticles" phenotype.
98.9% of hhts2/hhAC ovarioles contain multi-chambered cysts. Branching of the fusome occurs closer to the anterior end of the germarium than in wild type.
No segmentation is seen in hhAC mutant embryos. Naked cuticle is absent and no denticle diversity is seen (only type 5 denticles are present).
The gnathal lobes are reduced in mutant embryos.
Homozygous embryos show a segment polarity phenotype. Large clones in the posterior compartment of the wing have a similar phenotype to dispS037707 clones, except that wing vein L4 is additionally disrupted.
When analysed in large clones in the developing eye the packing in the ommatidial clusters is disrupted.
When wgScer\UAS.cLa is driven by Scer\GAL4en-e16E in a hhAC embryo, denticle rows 2, 3 and 4 are replaced by naked cuticle. Rows 5 and 6 are replaced by small denticles. In heterozygotes for hhAC, carrying wgScer\UAS.cLa and Scer\GAL4en-e16E, occasional breaches in the normal denticle belts occur as patches of naked cuticle, revealing a dosage sensitivity to the requirement for hh function at the segment border.
Homozygous clones can block the development of large portions of the external genitalia in males; in extreme cases the external genitalia consist of only portions of the anal plate and claspers and the penis apparatus is completely absent. The female genitalia are less affected by homozygous clones; the long bristles are absent and the thorn bristles are duplicated.
Double mutant phenotype with CrebA mutants is additive.
Clones situated entirely within the eye field do not affect morphogenetic furrow propogation or ommatidial differentiation. Only in the centre of large clones is the progression of the morphogenetic furrow retarded relative to the adjacent tissue. hh secreted from the neighbouring wild type ommatidia rescues, in a nonautonomous manner, loss of hh. Clones that span the lateral or posterior margin of the eye exhibit no neuronal differentiation. Marginal clones lead to the formation of naked cuticle in the eye.
Clones in the developing eye cause no effect on the progression of the furrow other than a very subtle retardation, even when the clones are large.
Small clones of this allele in the eye have no effect, large clones have a non-cell autonomous disrupting effect on the array of rows and columns of the ommatidia, fused ommatidia and (rarely) loss of retinal tissue. Strong enhancer of gl3.
Extreme hh cuticle phenotype when heterozygous with hh9, or when homozygous. Head segments fail to involute, naked cuticle portion of segment lost causing half size embryos with a lawn of denticles. When heterozygous with hh4 at 18oC, adults show extreme mutant eye phenotype, also seen when heterozygous with hhbar3. Homozygous embryos exhibit failure head involution and loss of naked cuticle from the posterior surface of each segment. Lethal when in homozygous or heterozygous combination with hh5, hh8 or hh9. Transheterozygotes with hh4 produce some adult survivors, at 18oC they display an eye phenotype. Transheterozygotes with hhbar3 display an eye phenotype at 25oC.