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General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
rbp1, rbpt99
Key Links
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 )
Disease-implicated variant(s)
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description

100% of brrbp-1/Y and brrbp-1/Dp(1;Y)Sz280 males have malrotated genitalia. This phenotype is rescued by the Dp(1;Y)y267g19.1 duplication.

brrbp-1 flies do not survive to eclosion. 100% reach pupal stage stage P6, 84% reach stage P12, and 80% become pharate adults.

The dorsoventral indirect flight muscles (DVMs) of mutant flies are still attached to the dorsal epidermis in pupae 14 hours after head eversion, but the connecting material is sparse. The dorsal ends of the muscles are narrower than in wild type, while the ventral ends appear normal. The dorsal myotendinous junction (MTJ) is defective, with the phenotype varying in severity. The area of muscle-tendon contact is reduced in mildly affected cases, although the muscle and tendon cell membranes do interdigitate and form spot adherens junctions. The number of tendon cell process extending from the dorsal epidermal muscle attachment site (EMA) is reduced. At the most aberrant MTJs, small numbers of tendon cell processes are tenuously linked to the muscle by strands of material that may be extracellular matrix or cellular debris. The sheath that surrounds the sparse and defective tendon processes is aberrant, with numerous gaps, especially along the medial side. The ventral MTJs appear normal at this stage.

br1/brrbp-1 mothers produce eggs that have reduced dorsal appendages, Eggs dissected from homozygous brrbp-1 females have dorsal appendages that are shorter than wild-type and irregular in shape, and the eggshell is fragile. brrbp-1/brnpr-6 females produce very few offspring.

Homozygotes arrest development at the early pupal or pharate adult stages.

DVM are virtually eliminated (a deficit in thoracic muscle precursors). DLM fibres often remain fused at their ends rather than splitting from three primordia into six DLM fibres. DLM, TTM and the few surviving DVM fibres occupy incorrect attachment sites on the dorsal thorax at epidermal locations normally occupied by other muscle fibres.

Heterozygotes with brrbp-4 have the salivary gland tangled in the head capsule and an abnormal proventriculus structure.

Failure of salivary gland degeneration. Reduction in dorso-ventral class of indirect flight muscles. Proventriculus abnormality: foregut-midgut junction less proventriculus-like in appearance.

Intermoult gene transcriptional phenotypes.

70% penetrance of abnormal SEG-TG separation phenotype, 84% with an abnormal optic lobe position and 51% with brain fusion failure in rbp mutants.

Thorax and appendages are slightly shorter or smaller than normal.

Pupae die with developed imaginal organs.

Heterozygotes with Df(1)br25 have normal viability and reduced bristle number on the palpus.

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by

brrbp-1 has lethal phenotype, enhanceable by Met27/Rst(1)JH[+]

Suppressor of

brrbp-1 is a suppressor of lethal | pupal stage phenotype of Msex\brZ4.hs

Phenotype Manifest In
Suppressor of

brrbp-1 is a suppressor of leg phenotype of Msex\brZ4.hs

Additional Comments
Genetic Interactions

brrbp-1/brrbp-1, Rst(1)JH27/+ double mutants die at an earlier stage (prepupal/early pupal) than brrbp-1/brrbp-1 mutants. brrbp-2/brrbp-1, Rst(1)JH27/Rst(1)JH27 flies are also prepupal/early pupal lethals. Expression of the Rst(1)JH+tSt-H.hs transgene can rescue the lethality of these flies.

Xenogenetic Interactions

When one copy of the Msex\brZ4.hs transgene is expressed in brrbp-1 mutant flies, only 1.5% of brrbp-1 mutants are 'rescued' to eclosion. Flies carrying two doses of Msex\brZ4.hs experience approximately 8% rescue to eclosion. Mutant brrbp-1 flies rescued with Msex\brZ4.hs typically die within 1-2 days of eclosion. These animals have a protracted proboscis and are most likely unable to feed. The malformed leg phenotype found in brrbp-1 animals that develop to late pupal stages is rescued in approximately 66% of cases by the expression of two Msex\brZ4.hs transgenes.

Complementation and Rescue Data
Fails to complement
Partially rescued by

brrbp-1 is partially rescued by brZ4.hs

brrbp-1 is partially rescued by brBRcore.Z4.hs

brrbp-1 is partially rescued by brBRcore.Z4.hs


Significant rescue of brrbp-1 mutant flies is observed with one copy of the brBRcore.TNT.Q1.Z1.hs transgene (64% survive to eclosion). Only marginal improvement in rescue (69% compared to 64%) is observed when two copies of brBRcore.TNT.Q1.Z1.hs are used. The majority of the rescued animals have normal legs.

Expression of one copy of brBRcore.Z4.hs in brrbp-1 mutant flies results rescue of only 7% of animals to eclosion. This increases to 13% when two copies are used. Mutant brrbp-1 flies rescued with brBRcore.Z4.hs typically die within 1-2 days of eclosion. These animals have a protracted proboscis and are most likely unable to feed. The malformed leg phenotype found in brrbp-1 animals that develop to late pupal stages is rescued in approximately 50% of cases by the expression of two brBRcore.Z4.hs transgenes.

brrbp-1/+ x brnpr-6/+ crosses lead to very few transheterozygous males but no females being produced. Offspring die as pupae. Complementation is based on lethality.

Over 50% of brrbp-1/Y males carrying two copies of either brBRcore.Q1.Z1.hs or brBRcore.TNT.Q1.Z1.hs are rescued to eclosion when brBRcore.Q1.Z1.hs or brBRcore.TNT.Q1.Z1.hs is expressed using a 33oC heat shock in 6 hour prepupae followed by a 37oC heat shock just after head emergence. The rescued animals are completely wild-type. brBRcore.Z4.hs partially rescues brrbp-1/Y males; 31% of brrbp-1/Y males carrying brBRcore.Z4.hs eclose when brBRcore.Z4.hs expression is induced in prepupae and pupae. The rescued flies have the brrbp-1 reduced bristle phenotype and are not fertile. brZ2.hs and brBRcore.NS.Z3.hs do not rescue brrbp-1/Y males.

Heat induced expression of P{hs-BRC-Z1} or P{hs-BRC-Z4} around the time of head eversion (approximately 12 hours after puparium formation) partially rescues the lethality. Heat induced expression of P{hs-BRC-Z1} completely rescues the DVM, expression of P{hs-BRC-Z4} only partially rescues and expression of P{hs-BRC-Z2} and P{hs-BRC-Z3} fail to rescue the DVM phenotype.

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Stocks (1)
Notes on Origin
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (5)
References (21)