FB2026_01 , released March 12, 2026
FB2026_01 , released March 12, 2026
Allele: Dmel\Ubxbx-3
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General Information
Symbol
Dmel\Ubxbx-3
Species
D. melanogaster
Name
FlyBase ID
FBal0017517
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
bx3
Key Links
Allele class
Mutagen
Nature of the Allele
Allele class
Progenitor genotype
Associated Insertion(s)
Cytology

Polytene chromosomes normal.

Description

Insertion of a gypsy element at map position -57kb. The direction of transcription of the gypsy element is in the opposite direction to Ubx transcription.

Mutations Mapped to the Genome
Curation Data
Type
Location
Additional Notes
References
Variant Molecular Consequences
Associated Sequence Data
DNA sequence
Protein sequence
 
Expression Data
Reporter Expression
Additional Information
Statement
Reference
 
Marker for
Reflects expression of
Reporter construct used in assay
Human Disease Associations
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 0 )
Disease
Evidence
References
Modifiers Based on Experimental Evidence ( 0 )
Disease
Interaction
References
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
 
Disease-implicated variant(s)
 
Phenotypic Data
Phenotypic Class
Phenotype Manifest In

adult muscle system & abdominal segment 1

ectoderm & metathoracic segment

Detailed Description
Statement
Reference

UbxLDN/Ubxabx-1 Ubxbx-3 Ubxpbx-1 adults show transformation of the distal part of the haltere (the capitellum) into the wing; the haltere is bigger than normal and has bristles on the margins and veins on the surface.

The anterior compartment is increased in size in Ubx130/Ubxbx-3 and Ubx6.28/Ubxbx-3 haltere discs.

The haltere is partially transformed to a wing in Ubxabx-1 Ubxbx-3 Ubxpbx-1/UbxLDN flies.

In Ubxbx-3 Ubxpbx-1 Ubx6.28 L3 larvae, tracheal metamere 3 is transformed into tracheal metamere 2. Tracheal metamere 2 appears normal.

Ubxbx-3/Df(3R)P2 flies show transformation of the anterior compartment of T3 (T3a) into the anterior compartment of T2 (T2a). The homeotically transformed T3 segment can contain DVM-I, DVM-III, DLM and DFM muscles. The homeotic DVM-I muscle is composed of one fibre and the diameter of the homeotic DVM-I fibre is less than that seen in T2. Homeotic DVM-II muscles are not seen. Ubxabx-1 Ubxbx-3 Ubx61d Ubxpbx-1/Df(3R)P2 mutants show transformation of T3 into T2 resulting in the replacement of halteres with a second set of wings. The homeotically transformed T3 segment resembles T2 in size. The homeotically transformed T3 segment can contain homeotic DVM-I, DVM-II, DVM-III, DLM and DFM muscles.

Ubxabx-1, Ubxbx-3 and Ubxpbx-1 triple mutants cause muscle patterning defects in A1 of pupae, transforming them towards a T3 thoracic identity.

Ubxabx-1 Ubxbx-3 Ubxpbx-1 triple mutant adults have four wings.

In Ubxabx-1 Ubxpbx-1 Ubxbx-3 triple mutant flies the T3 ectoderm transforms toward T2 identity. Transformation changes the pattern of myoblasts on the transformed haltere disc and their pattern of migration, but indirect flight muscles do not form as there are no larval templates. The haltere disc is almost completely transformed into a wing disc. Adults have two pairs of wings, but the homeotically transformed T3 has only rudimentary indirect flight muscles.

The giant fibre (GF) of Ubxabx-1 Ubxbx-3 Ubxpbx-1/Df(3R)P2 mutants makes a midline tuft and extends a lateral process to T2 and T3 segment. In the presence of ben1 the GF is capable of extending a process into the T3 segment but no lateral processes from the midline.

Flies triply mutant for Ubxabx-1, Ubxbx-3 and Ubxpbx-1 over Df(3R)P2 have a transformed metathorax including neural elements and jump muscle, that function in the escape-jump response within that segment. Corresponding transformation of the flight muscles is infrequent.

Ubx1/Ubxbx-3 transheterozygotes are viable, with the following transformations in the adult: T3a to T2a, T3p to T2p, and A1a to T3a.

Viability low but can be maintained homozygous. Halteres enlarged in heterozygote. Interactions with other Ubx 'bx' alleles described by Lewis (1951, 1955, 1963). Almost completely suppressed by su(Hw)2.

Does not affect the frequency of the trx bithorax-variegated phenotype in heterozygous combination with Df(3R)red-P52.

Ubxbx-3/Ubx130 flies show a strong transformation of anterior haltere to anterior wing. The proximal metathorax is transformed to proximal mesothorax.

Homozygotes and transheterozygotes of Ubx alleles demonstrate a significant enhancement of the bx phenotype when in combination with E(bx)2. Haltere to winglike and metanotum to mesonotumlike transformations are enhanced.

Different genetic combinations of Pc alleles and Ubx alleles suggest that the products of the bx region of Ubx are responsible for the "cbx" phenotype of the Pc mutations and in the absence of Pc the overexpression of bx gene products suppresses the pbx insufficiency phenotype in the posterior segments.

Haltere are transformed to wing and are 20-25% of wing size, dorsal tissue of T3 is incompletely transformed to metanotum, hypopleural plates are incompletely transformed to sternopleural plates, 8-10 hypopleural bristles are still present and the anterior third leg displays a strong transformation to anterior second leg, as seen by the bristle pattern. Phenotype can be suppressed by su(Hw) mutations.

Ubxbx-3 shows the "ppx" transformation at 17oC: ventral regions of T2p and T3p are affected.

Flies have normal transversal fascicles in the adult CNS.

Ubxbx-3 Ubxbxd-106/Df(3R)P115 clones in T3 show a transformation to T2 in legs and halteres. Clones in the posterior compartments of legs in T2 or T3 do not show transformation into prothorax.

Strong transformation of anterior third thoracic segment to second thoracic segment.

Homozygotes show a variable transformation of anterior haltere to wing. The transformed appendage is often misshapen, the most proximal sensilla fields are the most perfectly transformed, whereas the more distal fields often remain haltere-like. Dorsally on the transformed appendage, the ANWP and Teg. sensilla always appear normal, field d.Rad.A occasionally shows extra type-2 sensilla, the d.Rad.B and d.Rad.C fields often have fewer sensilla than normal, and the most distal sensilla have rudimentary sockets rather than smooth depressions. Sensilla on the medial radius are abnormal; d.Rad.D consists of aberrant type-5 sensilla not representative of wing or haltere, the d.Rad.E sensilla appear wing-like but crowded, and the dHCV and GSR sensilla of the distal radius are surrounded by extra sensilla of varying numbers and morphology. Ventrally, the v.Rad.A sensilla show normal morphology, although a fifth sensillum is often seen, the v.Rad.B sensilla are usually normal although they may be absent and the v.Rad.C field is sometimes replaced by fused, pedicellar-type sensilla which extend out over the more distal regions of the ventral radius. Ubxbx-3 Ubxpbx-1 flies show a transformation of haltere to wing. The transformed appendage is smaller than wild-type, the cuticle is often folded, and the veins are often obscure. The phenotype of the sensilla is similar to Ubxbx-3 homozygotes, except that the homeotic transformation in the proximal radius region is more complete, and d.Rad.D contains sensilla resembling, but not identical to, the pedicellar sensilla of the haltere. Ubxabx-1 Ubxbx-3 Ubxpbx-1 flies have a transformation of haltere to wing. The homeotic appendage is somewhat smaller than a normal wing, but usually has the full wild-type complement of wing sensilla, with each type located in the normal position and having normal morphology. The only exception is an occasional decrease in the number of sensilla in fields d.Rad.B and d.Rad.C, and rarely, one or a few extra haltere pedicellar bristles.

Hemizygous Ubxbx-3/Df(3R)P115 tissue shows a transformation of the metathoracic segment (both dorsal and ventral discs) to the mesothoracic segment in gynandromorphs. This transformation is restricted to the anterior compartment.

The frequency of variegated bithorax transformations seen in Df(3R)red-P52 heterozygotes is not increased in flies also heterozygous for Ubxbx-3.

Heterozygotes with Ubx61d has halteres partially wing-like but lack conversion of metanotum towards mesonotum.

The posterior portion of the halteres shows a slight wing-like modification in Ubxbx-3/Ubxpbx-1 flies.

External Data
Interactions
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Suppressed by
Statement
Reference

Ubxbx-3 has viable phenotype, suppressible by xen[+]/Asxxen-72-3

Other
Statement
Reference
Phenotype Manifest In
Enhanced by
Statement
Reference

Ubxbx-3 has phenotype, enhanceable by ash128

Ubxbx-3 has phenotype, enhanceable by ash218

Ubxbx-3 has phenotype, enhanceable by E(bx)1

Ubxbx-3 has haltere phenotype, enhanceable by zae(bx)

Suppressed by
Other
Statement
Reference
Additional Comments
Genetic Interactions
Statement
Reference

Heterozygosity for Asxxen-72-3 in a homozygous Ubxbx-3 mutant background causes lethality at the third instar larval stage.

The increased size of the anterior compartment that is seen in the haltere discs of Ubx6.28/Ubxbx-3 animals is partially suppressed by expression of tkvScer\UAS.cLa under the control of Scer\GAL4ptc-559.1.

Expression of abd-A1dB5.Scer\UAS results in an almost complete rescue of the transformed haltere phenotype of Ubxabx-1 Ubxbx-3 Ubxpbx-1/UbxLDN flies. The P{GawB}UbxLDN insertion within the UbxLDN flies drives expresssion of abd-A1dB5.Scer\UAS.

ssa Ubxbx-3 Ubxbxd-51j hemizygotes do not emerge as imagos. Dissection of late pupae reveals flies have four pairs of legs (Ubxbx-3 Ubxbxd-51j phenotype) and the fourth pair of legs exhibit severe disruption of segmentation and an improvement in the segmentation of the third pair.

Ubxabx-1 Ubxbx-3 Ubxpbx-1/Ubxlac1 combination transforms the metathorax into mesothorax (including transformation of halteres into wings). This phenotype can be rescued by Scer\GAL4Bx-MS1096 induced expression abd-A. Ectopic expression of Abd-B allows partial rescue.

Double heterozygotes for ash128 at 27oC exhibit haltere to wing transformation. No transformation phenotype is seen at 20oC. Double heterozygotes for ash218 at 27oC exhibit haltere to wing transformation and mild third to second leg transformation.

The Ubxbx-3/Ubxpbx-1 phenotype is enhanced by zae(bx).

Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Partially complements
Comments

The partial transformation of haltere into wing which is seen in UbxLDN/Ubxabx-1 Ubxbx-3 Ubxpbx-1 flies is strongly suppressed by expression of either UbxScer\UAS.cCa or UbxIIa.Scer\UAS.cRa under the control of Scer\GAL4Ubx-LDN.

The partial transformation of haltere into wing which is seen in UbxLDN/Ubxabx-1 Ubxbx-3 Ubxpbx-1 flies is partially suppressed by expression of one copy of UbxIVa.Scer\UAS.cRa under the control of Scer\GAL4Ubx-LDN and is almost completely suppressed by expression of two copies of UbxIVa.Scer\UAS.cRa under the control of Scer\GAL4Ubx-LDN.

Ubxabx-1 Ubxbx-3 Ubxpbx-1/Ubxlac1 combination transforms the metathorax into mesothorax (including transformation of halteres into wings). This phenotype can be rescued by Scer\GAL4Bx-MS1096 induced expression of Ubx.

Images (0)
Mutant
Wild-type
Stocks (12)
Notes on Origin
Discoverer

Stern, 2 Feb. 1925.

The original Ubxbx-3 chromosome had two insertions in Ubx, a gypsy insertion at -57kb and a Doc insertion at -53kb. Only the gypsy element is responsible for the Ubxbx-3 mutant phenotype: a recombinant chromosome without the Doc insertion has the same phenotype as the original chromosome, and loss of the gypsy insertion results in reversion of the Ubxbx-3 mutant phenotype.

Comments
Comments

The phenotype of a number of combinations of Ubx mutations has been investigated to determine the role of the bxd regulatory region in the modulation of Ubx expression.

External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (5)
References (62)