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General Information
Symbol
Dmel\bw
Species
D. melanogaster
Name
brown
Annotation Symbol
CG17632
Feature Type
FlyBase ID
FBgn0000241
Gene Model Status
Stock Availability
Gene Summary
brown (bw) encodes a member of the traffic ATPase (or ABC) family of membrane transporters. It is believed to heterodimerize with the product of w. bw and w are necessary to import guanine, a precursor for the red pteridine pigments, into pigment cells of the eyes, Malpighian tubules and testis sheath. [Date last reviewed: 2019-03-07] (FlyBase Gene Snapshot)
Also Known As

Plum

Key Links
Genomic Location
Cytogenetic map
Sequence location
Recombination map
2-103
RefSeq locus
NT_033778 REGION:23527805..23538499
Sequence
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
GO Summary Ribbons
Gene Ontology (GO) Annotations (13 terms)
Molecular Function (5 terms)
Terms Based on Experimental Evidence (2 terms)
CV Term
Evidence
References
inferred from mutant phenotype
inferred from mutant phenotype
(assigned by UniProt )
Terms Based on Predictions or Assertions (3 terms)
CV Term
Evidence
References
enables ATP binding
inferred from electronic annotation with InterPro:IPR003439, InterPro:IPR017871
(assigned by InterPro )
inferred from electronic annotation with InterPro:IPR017871
(assigned by InterPro )
inferred from sequence or structural similarity with UniProtKB:P10090
Biological Process (6 terms)
Terms Based on Experimental Evidence (5 terms)
CV Term
Evidence
References
involved_in guanine transport
inferred from mutant phenotype
(assigned by UniProt )
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
(assigned by UniProt )
Terms Based on Predictions or Assertions (2 terms)
CV Term
Evidence
References
traceable author statement
inferred from sequence or structural similarity with UniProtKB:P10090
Cellular Component (2 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (2 terms)
CV Term
Evidence
References
inferred from electronic annotation with InterPro:IPR005284
(assigned by InterPro )
is_active_in plasma membrane
inferred from biological aspect of ancestor with PANTHER:PTN000443095
(assigned by GO_Central )
Protein Family (UniProt)
Belongs to the ABC transporter superfamily. ABCG family. Eye pigment precursor importer (TC 3.A.1.204) subfamily. (P12428)
Summaries
Gene Snapshot
brown (bw) encodes a member of the traffic ATPase (or ABC) family of membrane transporters. It is believed to heterodimerize with the product of w. bw and w are necessary to import guanine, a precursor for the red pteridine pigments, into pigment cells of the eyes, Malpighian tubules and testis sheath. [Date last reviewed: 2019-03-07]
Gene Group (FlyBase)
ABCG ATP-BINDING CASSETTE TRANSPORTER SUBFAMILY -
The ATP-binding cassette (ABC) transporter family are primary active transporters that use ATP hydrolysis to drive the transport of substrates across the membrane. In metazoans the ABCG subfamily are half transporters. Half transporters must dimerize to form a functional transporter. (Adapted from FBrf0224053).
Protein Function (UniProtKB)
Part of a membrane-spanning permease system necessary for the transport of pigment precursors into pigment cells responsible for eye color. Brown and white dimerize for the transport of guanine.
(UniProt, P12428)
Phenotypic Description (Red Book; Lindsley and Zimm 1992)
bw: brown
Eye color light brownish wine on emergence, darkening to garnet. Red pigments lacking. Xanthommatin mostly replaced by dihydroxanthommatin (Phillips, Forrest, and Kulkarni, 1973, Genetics 73: 45-56). Pigment granules present but somewhat smaller than in wild type. Adult testes and vasa colorless. Larval Malpighian tubules pale yellow (Beadle, 1937, Genetics 22: 587-611). Produces white eyes in combination with v, cn, or st. Eye color autonomous when transplanted into wild-type host (Beadle and Ephrussi, 1936, Genetics 21: 230). RK1.
*bwA: brown-Auburn
Nearly uniform brown but with extra Y chromosome shows strong variegation. Homozygote usually lethal. RK1A.
bw4
Homozygotes have normal eye color; in heterozygotes with other alleles, red pigment is reduced. bw4/bw5 is purpleoidlike. bw4/bw like bw but darker. RK3.
bw5
bw5/bw4 is purpleoidlike (see bw4); bw5/bw is light yellowish brown; bw5/+ is wild type; bw5/bw5 is lethal. RK2A.
bw6
A subliminal recessive allele of bw; homozygotess are wild type in all combinations except in flies that are homozygous or hemizygous for wco2, which are like bw or wco. bw6/bw4 suppresses wco2, but all other heterozygotes between bw6 and bw alleles which were tested did not suppress. RK1 in combination with wco2.
bwa: brown-amber
Eye color light brownish yellow. Adult testes and vasa colorless. Larval Malpighian tubules slightly paler yellow than wild type. bwa/bw gives eye color slightly lighter than bw. RK1.
bwD: brown-Dominant
Eye color varies with age from purple to brown. Shows slight variegation in combination with st (Slatis, 1955). Wings pebbled. bwD/+ shows nearly a 100-fold reduction in pteridine levels; no accumulation of bw RNA detectable. bwD/bwVI > bwD/+ > bwD/bwD in severity of effect (Henikoff, and Dreesen, 1989, Proc. Nat. Acad. Sci. USA 86: 6704-08). Variegation suppressed by extra Y chromosomes (Brosseau, 1959, DIS 33: 123). Homozygote viable and fertile. Larval Malpighian tubules bright yellow (Brehme and Demerec, 1942, Growth 6: 351-56). RK1A.
*bwptm: brown:pteridine modifier
Undetectable in wild-type background. In wsat or wcf flies that are at the same time v, cn, or st, the amount of red eye pigment in +/+ > +/bwptm > bwptm/bwptm.
bwR: brown-Rearranged
These rearranged derivatives exhibit variegated phenotype in combination with +. Mostly homozygous lethal; survivors have brown eyes.
bwV1: brown-Variegated
Eye color like bw or pr, mottled with darker spots that deepen in red color with age. With st or v, has pale orange ground with dark orange spots. bwVI/bw shows sharply reduced levels of transcript from both the bw+ allele in cis with the rearrangement and the bw allele on the homologous second chromosome (Henikoff, and Dreesen, 1989, Proc. Nat. Acad. Sci. USA 86: 6704-08). Extra Y chromosome, as with other variegated browns, suppresses brown color, giving red eye sparsely speckled or splotched with darker spots. Amount of wild-type eye color also responds to fourth-chromosome constitution; 4/C(4) > C(4) = 4/4 > 4/0, with the first approaching wild type and the latter nearly bw (Lindsley and Rokop). Larval Malpighian tubules normal (Glass, Brehme). Generally lethal homozygous and in combination with other brown-Variegateds. Heterozygotes fully viable and fertile. RK1A.
Gene Model and Products
Number of Transcripts
2
Number of Unique Polypeptides
1

Please see the JBrowse view of Dmel\bw for information on other features

To submit a correction to a gene model please use the Contact FlyBase form

Protein Domains (via Pfam)
Isoform displayed:
Pfam protein domains
InterPro name
classification
start
end
Protein Domains (via SMART)
Isoform displayed:
SMART protein domains
InterPro name
classification
start
end
Comments on Gene Model

Gene model reviewed during 5.52

Gene model reviewed during 5.44

Gene model reviewed during 5.57

Mutation in sequenced strain: complex; multiple in-frame stops; see allele report bw[1]..

Sequence Ontology: Class of Gene
Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0072117
2738
675
FBtr0346612
2498
675
Additional Transcript Data and Comments
Reported size (kB)

3.0, 2.8 (northern blot)

Comments
External Data
Crossreferences
Polypeptide Data
Annotated Polypeptides
Name
FlyBase ID
Predicted MW (kDa)
Length (aa)
Theoretical pI
RefSeq ID
GenBank
FBpp0072026
75.9
675
7.41
FBpp0312192
75.9
675
7.41
Polypeptides with Identical Sequences

The group(s) of polypeptides indicated below share identical sequence to each other.

675 aa isoforms: bw-PA, bw-PD
Additional Polypeptide Data and Comments
Reported size (kDa)
Comments
External Data
Subunit Structure (UniProtKB)

Heterodimer of brown with white.

(UniProt, P12428)
Linkouts
Sequences Consistent with the Gene Model
Mapped Features

Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\bw using the Feature Mapper tool.

External Data
Crossreferences
Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
Linkouts
Expression Data
Expression Summary Ribbons
Colored tiles in ribbon indicate that expression data has been curated by FlyBase for that anatomical location. Colorless tiles indicate that there is no curated data for that location.
For complete stage-specific expression data, view the modENCODE Development RNA-Seq section under High-Throughput Expression below.
Transcript Expression
Polypeptide Expression
mass spectroscopy
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data
Marker for
 
Subcellular Localization
CV Term
Evidence
References
Expression Deduced from Reporters
High-Throughput Expression Data
Associated Tools

GBrowse - Visual display of RNA-Seq signals

View Dmel\bw in GBrowse 2
RNA-Seq by Region - Search RNA-Seq expression levels by exon or genomic region
Reference
See Gelbart and Emmert, 2013 for analysis details and data files for all genes.
Developmental Proteome: Life Cycle
Developmental Proteome: Embryogenesis
External Data and Images
Linkouts
BDGP expression data - Patterns of gene expression in Drosophila embryogenesis
DRscDB - A single-cell RNA-seq resource for data mining and data comparison across species
EMBL-EBI Single Cell Expression Atlas - Single cell expression across species
FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
FlyAtlas2 - A Drosophila melanogaster expression atlas with RNA-Seq, miRNA-Seq and sex-specific data
Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
Flygut - An atlas of the Drosophila adult midgut
Images
FlyExpress - Embryonic expression images (BDGP data)
  • Stages(s) 11-12
  • Stages(s) 13-16
Alleles, Insertions, Transgenic Constructs, and Aberrations
Classical and Insertion Alleles ( 139 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 21 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of bw
Transgenic constructs containing regulatory region of bw
Aberrations (Deficiencies and Duplications) ( 39 )
Alleles Representing Disease-Implicated Variants
Phenotypes
For more details about a specific phenotype click on the relevant allele symbol.
Lethality
Allele
Sterility
Allele
Other Phenotypes
Allele
Phenotype manifest in
Allele
Orthologs
Human Orthologs (via DIOPT v8.0)
Homo sapiens (Human) (17)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
3 of 15
Yes
No
3 of 15
Yes
No
2 of 15
No
No
2 of 15
No
No
2 of 15
No
No
1 of 15
No
No
1  
1 of 15
No
No
1  
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Model Organism Orthologs (via DIOPT v8.0)
Mus musculus (laboratory mouse) (22)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
3 of 15
Yes
No
3 of 15
Yes
No
3 of 15
Yes
No
2 of 15
No
No
2 of 15
No
No
2 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Rattus norvegicus (Norway rat) (24)
3 of 13
Yes
No
3 of 13
Yes
No
3 of 13
Yes
No
2 of 13
No
No
2 of 13
No
Yes
2 of 13
No
Yes
2 of 13
No
No
2 of 13
No
No
2 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
Yes
1 of 13
No
Yes
Xenopus tropicalis (Western clawed frog) (12)
3 of 12
Yes
No
2 of 12
No
Yes
2 of 12
No
No
2 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
Danio rerio (Zebrafish) (15)
3 of 15
Yes
No
3 of 15
Yes
No
3 of 15
Yes
No
3 of 15
Yes
No
3 of 15
Yes
No
2 of 15
No
No
2 of 15
No
No
2 of 15
No
No
2 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Caenorhabditis elegans (Nematode, roundworm) (17)
6 of 15
Yes
No
6 of 15
Yes
No
6 of 15
Yes
No
4 of 15
No
No
3 of 15
No
No
3 of 15
No
No
3 of 15
No
No
3 of 15
No
No
3 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Arabidopsis thaliana (thale-cress) (24)
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
Yes
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
No
2 of 9
Yes
Yes
2 of 9
Yes
Yes
1 of 9
No
No
Saccharomyces cerevisiae (Brewer's yeast) (10)
4 of 15
Yes
No
3 of 15
No
No
3 of 15
No
No
3 of 15
No
No
3 of 15
No
No
3 of 15
No
No
2 of 15
No
No
2 of 15
No
No
2 of 15
No
No
2 of 15
No
No
Schizosaccharomyces pombe (Fission yeast) (2)
2 of 12
Yes
No
2 of 12
Yes
No
Ortholog(s) in Drosophila Species (via OrthoDB v9.1) ( EOG091903ZH )
Organism
Common Name
Gene
AAA Syntenic Ortholog
Multiple Dmel Genes in this Orthologous Group
Drosophila suzukii
Spotted wing Drosophila
Drosophila simulans
Drosophila sechellia
Drosophila erecta
Drosophila yakuba
Drosophila ananassae
Drosophila pseudoobscura pseudoobscura
Drosophila persimilis
Drosophila willistoni
Drosophila virilis
Drosophila mojavensis
Drosophila grimshawi
Orthologs in non-Drosophila Dipterans (via OrthoDB v9.1) ( EOG09150285 )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Musca domestica
House fly
Glossina morsitans
Tsetse fly
Mayetiola destructor
Hessian fly
Aedes aegypti
Yellow fever mosquito
Anopheles darlingi
American malaria mosquito
Anopheles gambiae
Malaria mosquito
Culex quinquefasciatus
Southern house mosquito
Orthologs in non-Dipteran Insects (via OrthoDB v9.1) ( EOG090W020J )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Acyrthosiphon pisum
Pea aphid
Orthologs in non-Insect Arthropods (via OrthoDB v9.1) ( None identified )
No non-Insect Arthropod orthologies identified
Orthologs in non-Arthropod Metazoa (via OrthoDB v9.1) ( None identified )
No non-Arthropod Metazoa orthologies identified
Paralogs
Paralogs (via DIOPT v8.0)
Drosophila melanogaster (Fruit fly) (28)
4 of 10
4 of 10
4 of 10
4 of 10
4 of 10
4 of 10
4 of 10
4 of 10
4 of 10
4 of 10
3 of 10
3 of 10
3 of 10
3 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
Human Disease Associations
FlyBase Human Disease Model Reports
    Disease Model Summary Ribbon
    Disease Ontology (DO) Annotations
    Models Based on Experimental Evidence ( 0 )
    Allele
    Disease
    Evidence
    References
    Potential Models Based on Orthology ( 0 )
    Human Ortholog
    Disease
    Evidence
    References
    Modifiers Based on Experimental Evidence ( 1 )
    Allele
    Disease
    Interaction
    References
    Disease Associations of Human Orthologs (via DIOPT v8.0 and OMIM)
    Note that ortholog calls supported by only 1 or 2 algorithms (DIOPT score < 3) are not shown.
    Functional Complementation Data
    Functional complementation data is computed by FlyBase using a combination of the orthology data obtained from DIOPT and OrthoDB and the allele-level genetic interaction data curated from the literature.
    Interactions
    Summary of Physical Interactions
    esyN Network Diagram
    Interactions Browser
    Summary of Genetic Interactions
    esyN Network Diagram
    esyN Network Key:
    Suppression
    Enhancement

    Please look at the allele data for full details of the genetic interactions
    Starting gene(s)
    Interaction type
    Interacting gene(s)
    Reference
    Starting gene(s)
    Interaction type
    Interacting gene(s)
    Reference
    suppressible
    External Data
    Subunit Structure (UniProtKB)
    Heterodimer of brown with white.
    (UniProt, P12428 )
    Linkouts
    BioGRID - A database of protein and genetic interactions.
    DroID - A comprehensive database of gene and protein interactions.
    MIST (genetic) - An integrated Molecular Interaction Database
    MIST (protein-protein) - An integrated Molecular Interaction Database
    Pathways
    Signaling Pathways (FlyBase)
    Metabolic Pathways
    External Data
    Linkouts
    Genomic Location and Detailed Mapping Data
    Chromosome (arm)
    2R
    Recombination map
    2-103
    Cytogenetic map
    Sequence location
    FlyBase Computed Cytological Location
    Cytogenetic map
    Evidence for location
    59E2-59E3
    Limits computationally determined from genome sequence between P{lacW}l(2)s4830s4830&P{lacW}chrwk06908 and P{PZ}Dcp-102132
    Experimentally Determined Cytological Location
    Cytogenetic map
    Notes
    References
    Experimentally Determined Recombination Data
    Left of (cM)
    Right of (cM)
    Notes
    Stocks and Reagents
    Stocks (2,408)
    Genomic Clones (15)
     

    Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete

    cDNA Clones (131)
     

    Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.

    cDNA clones, fully sequenced
    BDGP DGC clones
    Other clones
      Drosophila Genomics Resource Center cDNA clones

      For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.

      cDNA Clones, End Sequenced (ESTs)
      RNAi and Array Information
      Linkouts
      DRSC - Results frm RNAi screens
      GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
      Antibody Information
      Laboratory Generated Antibodies
       
      Commercially Available Antibodies
       
      Other Information
      Relationship to Other Genes
      Source for database identify of
      Source for database merge of
      Additional comments

      Alleles designated bwR: brown-Rearranged were X-ray-induced derivatives of bw or bw+ by Slatis, 48k16. (Slatis, 1955). They exhibit variegated phenotype in combination with +. Mostly homozygous lethal; survivors have brown eyes. More complete descriptions in Lindsley and Grell, 1968. All associated with chromosome rearrangements with one breakpoint in 59DE and one in proximal heterochromatin.

      Other Comments

      bw can be simultaneously acted upon by pericentric and distal blocks of heterochromatin.

      An element, P{Prat:bw} encoding a very low pigment level has been used to generate tandem arrays of up to 19 transposon copies at cytological location 65A10. The tandem arrays have altered polytene chromosome morphology.

      One of a class of genes with TATA-less promoters that have a subset of the conserved DPE sequence.

      Fluorescent in situ hybridisation (FISH) to interphase diploid nuclei demonstrates that the insertion of heterochromatin into bw causes the aberrant association of bw and its homologous copy with heterochromatin. The cytological association of the heterochromatic region is affected by chromosomal distance from heterochromatin and by genic modifiers of PEV.

      Studies of PEV using a transposon-borne bw allele support a model in which local alterations affect the affinity of a gene region for nearby heterochromatin via homology-based pairing, rather than heterochromatin being propagated along the chromosome.

      Transcripts of bw, st and w are all modulated by Inr-b in a developmentally-specific manner.

      Dp(?;2)bwD position effect variegation (PEV) is observed as the very strong dominant variegating effect on the bw+ copy present on the homologous chromosome. Dp(?;2)bwD fails to coalesce with the chromocenter when its position along the chromosome places it beyond a threshold distance from heterochromatin. This threshold depends upon configuration of Dp(?;2)bwD chromosome and its paired homolog. The basis of silencing is paractivation across paired copies of the duplication as opposed to cis-spreading along the chromosome.

      The D.virilis and D.melanogaster bw genes show functional conservation: Dvir\bw+ rescues the D.melanogaster mutant bw phenotype. Sequences required for transactivation are also conserved as Dvir\bw in D.melanogaster shows dominant PEV.

      Dvir\bw transformed into D.melanogaster can be expressed. Induction of a PEV mutation in the Dvir\bw transgene reveals that Dvir\bw is capable of being trans-inactivated in D.melanogaster. These results support the conclusion that sequences responsible for trans-inactivation are conserved to regulate bw expression.

      A fifth of mutations selected on the basis of suppression of bwD carry rearrangements that modify PEV by changing the chromosomal position of bwD, suggesting that PEV depends on nuclear position.

      The sequence-specific component of the bw locus that is responsible for trans-inactivation may be the site at which a bw-specific transcription factor binds. Deletion analysis of the 8.4kb EcoRI fragment carrying the wild type bw+t8.4 from the P{bw+L}92C construct demonstrates that a 3.8kb fragment containing the bw coding region and 850bp of upstream sequences includes the genetic element responsible for trans-inactivation.

      Chromatographic pattern of pteridine eye pigments neodrosopterin, sepiapterin, pterin, aurodrosopterin, acetyldihidrohomopterin, isoxanthopterin, biopterin and drosopterin measured in bw alleles.

      Analysis of variance of developmental time and viability of pteridine pathway mutants in sf, se, Hn, dke and bw, indicated that viability of induced and natural population alleles is the same whereas developmental time tends to be longer for induced mutations as compared to natural population alleles.

      Trans inactivation at bw requires some feature or component of heterochromatin, somatic pairing between variegating and wild-type alleles and a sequence in or near the bw gene in trans to the source of the heterochromatin. 35 lines carrying ectopic copies of bw were examined in the presence of dominant "bwV" alleles: no mutant spots or clones characteristic of trans-inactivation were seen. One transformant, "R26", has the P element construct colocalized with the resident bw+ and was trans-inactivated, suggesting that trans-inactivation is a chromosome-local phenomenon. Induction of position effect variegation on an ectopic copy of bw by chromosome rearrangement causes trans-inactivation of its paired homolog. Excisions and deletions of the copy of bw in cis to the rearrangement partially suppress transinactivation in a size-dependent manner, as if local somatic pairing (disrupted by the deletions) is necessary for trans-inactivation to occur.

      bw has no substantial affect on ommochrome pigmentation in the fat body, ocelli or tubules.

      Ultrastructure and Ca-sequestering properties of eye colour pigment granules (PGs) are studied in the eyes of wild type and mutant flies. A new type of ommochrome PG localises in primary pigment cells and basal terminals of the processes of Semper cells. At room temperature these PGs exhibit OsO4-dependent structural ability. X ray microanalysis revealed a less Ca-binding ability of the PGs as compared to those in secondary pigment cells.

      Transinactivation at the bw gene is antimorphic, occurs at the level of mRNA accumulation and is sensitive to certain structural configurations of the bw chromosomal region.

      A bw cDNA has been cloned and sequenced.

      Mutant alleles are useful as markers in clonal analysis.

      Uptake studies indicate that bw, like w, blocks the transport of guanine and xanthine, likely pteridine precursors (Sullivan and Sullivan, 1975). Sequence comparisons between the predicted bw- and w-encoded proteins show that they are similar to one another and to subunits of active transport family members (Mount, 1987; Dreesen, Johnson and Henikoff, 1988).

      Origin and Etymology
      Discoverer

      Waaler, 15th Oct. 1919.

      Etymology
      Identification
      External Crossreferences and Linkouts ( 52 )
      Sequence Crossreferences
      NCBI Gene - Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes, and links to genome-, phenotype-, and locus-specific resources worldwide.
      GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
      GenBank Protein - A collection of sequences from several sources, including translations from annotated coding regions in GenBank, RefSeq and TPA, as well as records from SwissProt, PIR, PRF, and PDB.
      RefSeq - A comprehensive, integrated, non-redundant, well-annotated set of reference sequences including genomic, transcript, and protein.
      UniProt/Swiss-Prot - Manually annotated and reviewed records of protein sequence and functional information
      UniProt/TrEMBL - Automatically annotated and unreviewed records of protein sequence and functional information
      Other crossreferences
      BDGP expression data - Patterns of gene expression in Drosophila embryogenesis
      Drosophila Genomics Resource Center - Drosophila Genomics Resource Center (DGRC) cDNA clones
      DRscDB - A single-cell RNA-seq resource for data mining and data comparison across species
      EMBL-EBI Single Cell Expression Atlas - Single cell expression across species
      Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
      FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
      FlyAtlas2 - A Drosophila melanogaster expression atlas with RNA-Seq, miRNA-Seq and sex-specific data
      Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
      Flygut - An atlas of the Drosophila adult midgut
      GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
      KEGG Genes - Molecular building blocks of life in the genomic space.
      MARRVEL_MODEL - MARRVEL (model organism gene)
      modMine - A data warehouse for the modENCODE project
      Linkouts
      BioGRID - A database of protein and genetic interactions.
      DroID - A comprehensive database of gene and protein interactions.
      DRSC - Results frm RNAi screens
      FlyCyc Genes - Genes from a BioCyc PGDB for Dmel
      FlyMine - An integrated database for Drosophila genomics
      MIST (genetic) - An integrated Molecular Interaction Database
      MIST (protein-protein) - An integrated Molecular Interaction Database
      Synonyms and Secondary IDs (14)
      Reported As
      Secondary FlyBase IDs
        Datasets (0)
        Study focus (0)
        Experimental Role
        Project
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        References (356)