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General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
cactA2, cactusA2
Nature of the Allele
Mutations Mapped to the Genome
Additional Notes
Associated Sequence Data
DNA sequence
Protein sequence
Progenitor genotype
Nature of the lesion
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 ( 0 )
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description

cact7 embryos exhibit a strong ventralized phenotype; the laterally derived cephalic fold initiates dorsally after the onset of gastrulation.

Homozygous and cact7/cactE10R01 mutant third instar larvae have melanotic nodules found in the hemocoel or in association with He-positive lymph glands. They also show gut melanisation not accompanied by tissue overgrowth or hemocyte encapsulation.

Approximately half of the melanotic nodules found in cact7 larvae are surrounded by lamellocytes, while the other half consist of tissue agglomerates that contain one or more melanised foci and also tube-like structures, which are possibly tracheae, visceral muscles and polyploid cells.

cact7 flies show similar mortality levels to wild-type flies in response to feeding with both the ROS-resistant KNU53775 yeast strain and a standard yeast strain (W303).

The concentration of circulating hemocytes in homozygous larvae is increased compared to controls. The fraction of podocytes and lamellocytes is increased compared to controls.

Lamellocytes appear in circulation during the second instar stage in cact7/cact3 larvae and are abundant in the hemolymph of third instar larvae (5-20%), where they participate in the formation of melanotic tumours. The crystal cell population is not affected. Lamellocytes are present in the lymph glands of third instar mutant larvae.

About 30% of cact7 heterozygotes die as embryos and show mostly a weak ventralised phenotype.

Embryos derived from dl1 cact7 mothers carrying either dl+mWT, dlS70A, dlS79A, dlS103A or dlS213A are strongly ventralised and do not hatch. Embryos derived from dl1 cact7 mothers carrying dlS312A are severely dorsalised. Embryos derived from dl1 cact7 mothers carrying dlS317A are lateralised.

Larvae contain free-floating melanotic masses.

30% of eggs laid by heterozygous females do not hatch and are weakly ventralised. The fraction of eggs that do not hatch is increased if the female also carries dlRHR.Hsp83.T:Ecol\lacZ, dl84-342.Hsp83.T:Ecol\lacZ, dl138-342.Hsp83.T:Ecol\lacZ or dl222-342.Hsp83.T:Ecol\lacZ.

In the absence of immune challenge the antifungal gene Drs is constitutively expressed.

Homozygous females produce strongly ventralised embryos. Larvae exhibit a melanotic tumour phenotype. There is some lethality at the end of the larval stage.

Cell intercalation in lateralized cact mutant embryos proceeds normally during germ band extension.

72% of embryos from heterozygous mothers hatch, but none hatch in presence of additional dl protein. Females transheterozygous for a cact gain of function allele and a loss of function allele result in embryos in which ventral structures are progressively lost at the expense of dorsal structures as the strength of the loss of function allele increases.

Interacts with RpII140wimp maternal effect.

Ventralized embryos: rings or patches of ventral denticles along dorsoventral axis, expansion of mesoderm at expense of ectoderm. Altered pattern of dpp and zen and expansion of twi and sna expression domain.

Strong ventralizing phenotype: lack of all dorsally and laterally derived structures and the expansion of the ventral epidermis around the entire circumference. Expansion of twi expression in terminal regions.

Very strong cact allele.

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by
Suppressed by
NOT suppressed by
Phenotype Manifest In
Additional Comments
Genetic Interactions

weklor, cact7 embryos show a lateralized phenotype, as revealed by the presence of rings of laterally derived ventral denticle belts.

Many of the melanotic nodules seen in cact7 dl2 double mutant larvae are of hematopoietic origin; they are located in the hemocoel and lymph glands and consist of large, flat F-actin-rich lamellocytes or both lamellocyte and plasmatocyte-like cells. Melanotic agglomerates containing different tissue types are not seen in the double mutants (in contrast to cact7 single mutants).

The concentration of circulating hemocytes in mxcG43/Y ; cact7/cact7 larvae is less than the number seen in either single mutant. The lymph glands of the double mutant larvae are very fragile, show severe overgrowth and contain high numbers of differentiated blood cells. There is intense mitotic activity in these glands. There is no increase in apoptotic cell death in these glands.

The addition of cactinScer\UAS.cLa driven by Scer\GAL4arm.PS to cact7 homozygotes leads to a marked decrease in fertility and an enhancement of the ventralised phenotype.

cact7 domk08108 double mutant larvae contain melanotic masses, although their frequency is markedly reduced compared to cact7 single mutant larvae and the masses are devoid of hemocytes.

The zygotic semi-lethality of cact7 homozygotes is not suppressed by gd2, snk1, snk2, eaD4, ea2, spz2, spz4 or dl1. The zygotic semi-lethality of cact7 homozygotes is strongly suppressed by Tlr2/Df(3R)ro80b, tub2 or pll10/pll1.

Xenogenetic Interactions
Complementation and Rescue Data
Partially rescued by
Not rescued by
Images (0)
Stocks (1)
Notes on Origin

Overexpression of dl phenocopies the loss of function mutant cact phenotype.

P{Dipt2.2-lacZ} is not induced in homozygous larvae.

cact7 dl1 double mutants also exhibit melanotic tumours.

External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (4)
References (41)