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General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Key Links
Nature of the Allele
Mutations Mapped to the Genome
Additional Notes
Associated Sequence Data
DNA sequence
Protein sequence
Nature of the lesion

Deletion removing the start of the open reading frame.

Deletion beginning in P{PZ}hhP30 (i.e. at coordinate 0) extending to +8.6kb. Deletion of sequences beginning in the P-element insertion and extending to between position +0.8 to +8.6 (coordinate 0 is the P{lacZ} insertion of hhP30), removing the hh promoter and part of the coding region.

Insertion components
Expression Data
Reporter Expression
Additional Information
Marker for
Reflects expression of
Reporter construct used in assay
Human Disease Associations
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 0 )
Modifiers Based on Experimental Evidence ( 1 )
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
Disease-implicated variant(s)
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description

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.

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhancer of

hhAC is an enhancer of visible phenotype of RetMEN2B.GMR

hh[+]/hhAC is an enhancer of visible phenotype of CycEJP

NOT Enhancer of
Suppressor of

hh[+]/hhAC is a suppressor | partially of visible | adult stage phenotype of wdpKO.ΔCDS

hh[+]/hhAC is a suppressor of hyperplasia phenotype of boie01708

hhAC is a suppressor of visible | homeotic | somatic clone phenotype of pb5

hh[+]/hhAC is a suppressor of visible phenotype of Scer\GAL4sca-109-68, atoUAS.cJa

Phenotype Manifest In
Suppressed by
Enhancer of

hh[+]/hhAC is an enhancer of eye | heat sensitive phenotype of Df(3R)p13/ato1090

hh[+]/hhAC is an enhancer of photoreceptor neuron | heat sensitive phenotype of Df(3R)p13/ato1090

hhAC is an enhancer of eye phenotype of RetMEN2B.GMR

hh[+]/hhAC is an enhancer of eye phenotype of CycEJP

hh[+]/hhAC is an enhancer of neuroblast | larval stage phenotype of trol13

hhAC is an enhancer of neuroblast | larval stage phenotype of trold8

hhAC is an enhancer of pigment cell phenotype of sgl05007, wa

NOT Enhancer of
Suppressor of
NOT Suppressor of

hhAC is a non-suppressor of phenotype of arm3

Additional Comments
Genetic Interactions

hhAC/+ significantly suppresses the increased percentage of mir-14Δ1/mir-14Δ1 mutant dorsal tracheal branches that have excess (>2) terminal cells.

Eye discs from flies expressing DlScer\UAS.cDa under the control of Scer\GAL4ey.PH and also carrying small patches of hhAC cells are 170% larger than control wild type eye discs, and 126% larger than flies expressing DlScer\UAS.cDa alone.

The follicle stem cell hyper-proliferation and excess follicle cell accumulation phenotypes are suppressed in boie01708 mutants by hhAC/+.

A hhAC heterozygous background gives a dominant enhancement to the ato1090/Df(3R)p13 eye phenotype at 25[o]C.

In embryos expressing wgScer\UAS.cLa under the control of Scer\GAL4en-e16E in a hhAC/hhAC background, naked cuticle is made over four to five cell diameters posterior as well as anterior to the en-expression domain. In these embryos, instead of denticle belts, a thin stripe of denticles similar to row 6 denticles are formed. In embryos expressing wgScer\UAS.cLa under the control of Scer\GAL4en-e16E in a hhAC/+ background, an intermediate phenotype is seen, with small regions of naked cuticle ("gaps") being found within denticle belts, often replacing denticle rows 2-5.

When mitotic clones induced in the labial disc are double mutant for both pb5 and hhAC, the labial-to-leg transformation is modified. Overall tissue size is reduced compared to pb5 single mutants and distinct leg tarsi can no longer be seen, although remaining tissue still has prothoracic leg identity, as evidenced by the presence of sex comb teeth.

Metameric furrows fail to form in armS10.Scer\UAS.T:Hsap\MYC; Scer\GAL4en-e16E embryos homozygous for hhAC. This phenotype is not suppressed by wgl-17/wgl-17.

Somatic clones in the abdomen that have partial loss of function for ptc (ptcS2) and hhAC show repolarisation of the back half of the clone and behind it.

Expression of wgScer\UAS.cLa under the control of Scer\GAL4en-e16E in hhAC embryos rescues the formation of neuroblast NB 7-3 95% of hemisegments.

hhAC ci94 double mutant embryos are indistinguishable from ci94 single mutant embryos. The addition of hhAC does not aggravate the ptc16 mutant phenotype.

87% of SxlM4 ; hhts2/hhAC ovarioles contain multi-chambered cysts.

hhAC ; ci94 double mutant embryos show a cuticle phenotype that is weaker than hhAC but stronger than ci94 single mutant embryos. Type 4 denticles are present.

Xenogenetic Interactions

Heterozygosity for hhAC does not modify the fully penetrant rough eye phenotype resulting from the co-expression of HPV18\E6Scer\UAS.T:Hsap\MYC and Hsap\UBE3AScer\UAS.cRa under the control of Scer\GAL4GMR.PU, leading to severe eye necrosis.

Complementation and Rescue Data
Partially rescued by
Not rescued by

Expression of hhN.Scer\UAS.cGa, under the control of Scer\GAL4unspecified rescues the hhAC phenotype.

Naked cuticle formation in hh15/hhAC embryonic cuticle is rescued by hhScer\UAS.cIa; Scer\GAL469B, but the denticle belts formed consist of only row 1 2 and 3 type denticles. Naked cuticle formation in hhAC homozygous embryonic cuticle is partially rescued by hhN.Scer\UAS.T:Ivir\HA1; Scer\GAL469B (some denticle belts are fused at the midline). The denticle belts formed consist of (A-P) a single row 1 type followed by a number of row 2, sometimes followed by a row 1. Naked cuticle formation in hhAC/hhAC embryos is not rescued by hhC85S.Scer\UAS; Scer\GAL469B. However the denticle lawn formed, is transformed from row 5 type, to bands of row 3 type denticles, separated by a single row 4 + an incomplete row 5.

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Stocks (2)
Notes on Origin
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (4)
References (74)