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General Information
Symbol
Dmel\Zw
Species
D. melanogaster
Name
Zwischenferment
Annotation Symbol
CG12529
Feature Type
FlyBase ID
FBgn0004057
Gene Model Status
Stock Availability
Enzyme Name (EC)
Glucose-6-phosphate dehydrogenase (NADP(+)) (1.1.1.49)
Gene Snapshot
Zwischenferment (Zw) encodes a cytosolic enzyme that catalyzes the oxidation of Glucose-6-phosphate to 6-phosphogluconate with the concomitant reduction of NADP[+] to NADPH. The products of Zw and Pgd are the two NADP[+] reducing enzymes in the pentose phosphate pathway. [Date last reviewed: 2019-03-21]
Also Known As

G6PD, glucose-6-phosphate dehydrogenase, G6PDH, G-6-PD, Glucose-6-phosphate DH

Key Links
Genomic Location
Cytogenetic map
Sequence location
X:19,667,252..19,672,353 [+]
Recombination map

1-63

RefSeq locus
NC_004354 REGION:19667252..19672353
Sequence
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
GO Summary Ribbons
Gene Ontology (GO) Annotations (6 terms)
Molecular Function (2 terms)
Terms Based on Experimental Evidence (1 term)
CV Term
Evidence
References
Terms Based on Predictions or Assertions (1 term)
CV Term
Evidence
References
inferred from electronic annotation with InterPro:IPR022674, InterPro:IPR022675
(assigned by InterPro )
Biological Process (4 terms)
Terms Based on Experimental Evidence (1 term)
CV Term
Evidence
References
inferred from mutant phenotype
Terms Based on Predictions or Assertions (3 terms)
CV Term
Evidence
References
inferred from sequence or structural similarity with UniProtKB:P11413
(assigned by UniProt )
inferred from sequence or structural similarity with UniProtKB:P11413
(assigned by UniProt )
Cellular Component (0 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (0 terms)
Protein Family (UniProt)
Belongs to the glucose-6-phosphate dehydrogenase family. (P12646)
Catalytic Activity (EC)
Experimental Evidence
D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5-lactone + NADPH (1.1.1.49)
Predictions / Assertions
-
Summaries
Gene Group (FlyBase)
OTHER CH-OH OXIDOREDUCTASES, NAD OR NADP AS ACCEPTOR -
The Other CH-OH oxidoreductases, NAD or NADP as acceptor group, is a collection of oxidoreductases that do not fit into any of the other major CH-OH oxidoreductases, NAD or NADP as acceptor group.
Protein Function (UniProtKB)
Cytosolic glucose-6-phosphate dehydrogenase that catalyzes the first and rate-limiting step of the oxidative branch within the pentose phosphate pathway/shunt, an alternative route to glycolysis for the dissimilation of carbohydrates and a major source of reducing power and metabolic intermediates for fatty acid and nucleic acid biosynthetic processes.
(UniProt, P12646)
Phenotypic Description (Red Book; Lindsley and Zimm 1992)
Zw: Zwischenferment
Structural gene for glucose 6-phosphate dehydrogenase (Zwischenferment of Warburg) [G6PD (E.C. 1.1.1.49)], the first enzyme in the oxidative part of the pentose phosphate shunt. Electrophoretic variants ZwA and ZwB have been described in Drosophila melanogaster (Young et al., 1964; Young, 1966). The G6PD produced by ZwA shows faster migration in starch gel (Young et al., 1964) or acrylamide gel (Peeples, Barnett, and Oliver, 1967, J. Hered. 58: 243-45) than that produced by ZwB. A ZwA/ZwB female shows fast- and slow-migrating bands but no hybrid band of intermediate mobility (Young et al., 1964; Steele et al., 1968; Hori and Tanda, 1980, Jpn. J. Genet. 55: 211-23). The B variant in both homo- and heterozygotes is characterized by a double band and shows more heat stability than the A variant (Steele et al., 1968). A dominant sex-linked modifier of the electrophoretic mobility of G6PD, M(G6PD), has been described by Komma (1968, Biochem. Genet. 1: 229-37). A regulatory element that affects the activity level of G6PD has been reported by Itoh and Hori (Jpn. J. Genet. 60: 441-53). The molecular weight of the A variant of G6PD approximates 147,000 and that of the B variant 317,000 according to Steele et al. (1968), who used the electrophoretic starch gel method and observed that the B form can dissociate and produce some A-like form. Lee, Langley, and Burkhart (1978, Anal. Biochem. 86: 697-706), using gel-filtration chromatography, reported that the B variant has a molecular weight of 240,000. A subunit molecular weight for the purified enzyme was estimated by Lee et al. to be 55,000 and by Hori and Tanda to be 69,000, as if the slow B variant represented a tetramer and the fast A variant a dimer of single polypeptides (Hori and Tanda, 1980; Miyashita et al., 1986). Significant amounts of the enzyme are found in the fat body and the intestine of Drosophila melanogaster larvae (Cochrane and Lucchesi, 1980, Genetics 94: s20). Enzyme levels are raised by dietary sucrose or D-glycerate (Geer, Kamiak, Kidd, Nishimura, and Yemm, 1976, J. Exp. Zool. 195: 15-31; Geer, Woodward, and Marshall, 1978, J. Exp. Zool. 203: 391-402; Cavener and Clegg, 1981; Cochrane, Lucchesi, and Laurie-Ahlberg, 1983, Genetics 105: 601-13). A maternal form of G6PD can be detected up to the early pupal stage (Gerasimova and Smirnova, 1979). Total G6PD activity increases during the larval period, reaches a peak during the third larval instar, drops during pupation, and increases again in the adult (Bijlsma and Van der Meulen-Bruijns, 1979, Biochem. Genet. 17: 1131-44; Williamson and Bentley, 1983). The enzyme shows a characteristic staining pattern in imaginal disks (Cunningham, Smith, Makowski, and Kuhn, 1983, Mol. Gen. Genet. 191: 238-43). Males with one dose of Zw+ and females with two doses have about the same amount of G6PD activity, i.e. show dosage compensation for enzyme activity (Seecof et al., 1969; Gvozdev et al., 1971; Bowman and Simmons, 1973; Faizullin and Gvozdev, 1973; Williamson and Bentley, 1981). Females heterozygous for a Zw deficiency show a corresponding reduction in enzyme activity; males and females with an extra dose of Zw+ show increased enzyme activity (Seecof et al., 1969; Maroni and Plaut, 1973; Stewart and Merriam, 1975). Contribution of each dose of G6PD to the level of enzyme activity is the same in triploid females as in diploid females (Lucchesi and Rawls, 1973). A number of low- and null-activity mutations have been induced at the Zw locus. The mutant alleles are fully viable (Gvozdev et al., 1976; Hughes and Lucchesi, 1977; Bijlsma, 1980; Lucchesi et al., 1979), but the larvae do not grow as well as wild type on a minimal amino-acid diet lacking fatty acids and whole nucleic acids (Geer et al., 1974). Null alleles at the ry locus are also viable, but double mutant combinations of Zw-;ry- do not survive (Lucchesi and Manning, 1988). Although Pgd- flies are lethal, Zw-Pgd- flies carrying null alleles for both G6PD, the first enzyme in the pentose phosphate shunt, and 6PGD, the last enzyme , are viable , presumably because the toxic 6-phosphogluconate is not produced (Hughes and Lucchesi, 1977, 1978; Geer et al., 1979; Lucchesi et al., 1979). Many natural populations throughout the world are polymorphic for the A and B variants (Oakeshott, Chambers, Gibson, Eanes, and Willcocks, 1983, Heredity 50: 67-72). Rare variants from a number of North American populations have been screened by sequential electrophoresis of starch and acrylamid gels to detect molecular heterogeneity (Eanes, 1983, 1984; Eanes and Hey, 1986); the G6PD activity of these lines and also of induced mutants has been measured (see the following table).
Gene Model and Products
Number of Transcripts
3
Number of Unique Polypeptides
2

Please see the GBrowse view of Dmel\Zw or the JBrowse view of Dmel\Zw 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 5.51

Gene model reviewed during 5.55

Sequence Ontology: Class of Gene
Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0074748
2092
524
FBtr0074749
2069
502
FBtr0340611
1797
502
Additional Transcript Data and Comments
Reported size (kB)

2.0 (longest cDNA)

2.0 (northern blot)

Comments
External Data
Crossreferences
Polypeptide Data
Annotated Polypeptides
Name
FlyBase ID
Predicted MW (kDa)
Length (aa)
Theoretical pI
RefSeq ID
GenBank
FBpp0074517
60.4
524
6.40
FBpp0074518
58.0
502
6.33
FBpp0309476
58.0
502
6.33
Polypeptides with Identical Sequences

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

502 aa isoforms: Zw-PB, Zw-PC
Additional Polypeptide Data and Comments
Reported size (kDa)

523 (aa); 60 (kD predicted)

Comments
External Data
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\Zw 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
expression microarray
Stage
Tissue/Position (including subcellular localization)
Reference
adult fat body

Comment: cyclical, peak ZT9-12

northern blot
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data

Expressed cyclically in the adult fat body.

The Zw transcript is detected in adult males and females.

Marker for
 
Subcellular Localization
CV Term
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\Zw 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
FLIGHT - Cell culture data for RNAi and other high-throughput technologies
FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
Flygut - An atlas of the Drosophila adult midgut
Images
Alleles, Insertions, and Transgenic Constructs
Classical and Insertion Alleles ( 123 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 8 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of Zw
Transgenic constructs containing regulatory region of Zw
Deletions and Duplications ( 1 )
Phenotypes
Orthologs
Human Orthologs (via DIOPT v8.0)
Homo sapiens (Human) (2)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
15 of 15
Yes
Yes
3 of 15
No
No
Model Organism Orthologs (via DIOPT v8.0)
Mus musculus (laboratory mouse) (3)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
15 of 15
Yes
Yes
12 of 15
No
Yes
3 of 15
No
No
Rattus norvegicus (Norway rat) (2)
10 of 13
Yes
Yes
3 of 13
No
No
Xenopus tropicalis (Western clawed frog) (2)
3 of 12
Yes
Yes
2 of 12
No
No
Danio rerio (Zebrafish) (2)
14 of 15
Yes
Yes
2 of 15
No
No
Caenorhabditis elegans (Nematode, roundworm) (1)
14 of 15
Yes
Yes
Arabidopsis thaliana (thale-cress) (6)
9 of 9
Yes
Yes
9 of 9
Yes
Yes
3 of 9
No
Yes
3 of 9
No
Yes
3 of 9
No
Yes
2 of 9
No
Yes
Saccharomyces cerevisiae (Brewer's yeast) (1)
14 of 15
Yes
Yes
Schizosaccharomyces pombe (Fission yeast) (3)
11 of 12
Yes
Yes
3 of 12
No
Yes
2 of 12
No
Yes
Orthologs in Drosophila Species (via OrthoDB v9.1) ( EOG091906QR )
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 ananassae
Drosophila pseudoobscura pseudoobscura
Drosophila persimilis
Drosophila willistoni
Drosophila virilis
Drosophila mojavensis
Drosophila grimshawi
Orthologs in non-Drosophila Dipterans (via OrthoDB v9.1) ( EOG0915038Z )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Musca domestica
House fly
Glossina morsitans
Tsetse fly
Lucilia cuprina
Australian sheep blowfly
Mayetiola destructor
Hessian fly
Aedes aegypti
Yellow fever mosquito
Anopheles darlingi
American malaria mosquito
Anopheles gambiae
Malaria mosquito
Anopheles gambiae
Malaria mosquito
Culex quinquefasciatus
Southern house mosquito
Orthologs in non-Dipteran Insects (via OrthoDB v9.1) ( EOG090W04IP )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Bombyx mori
Silkmoth
Danaus plexippus
Monarch butterfly
Heliconius melpomene
Postman butterfly
Apis florea
Little honeybee
Apis mellifera
Western honey bee
Bombus impatiens
Common eastern bumble bee
Bombus terrestris
Buff-tailed bumblebee
Linepithema humile
Argentine ant
Megachile rotundata
Alfalfa leafcutting bee
Nasonia vitripennis
Parasitic wasp
Dendroctonus ponderosae
Mountain pine beetle
Tribolium castaneum
Red flour beetle
Rhodnius prolixus
Kissing bug
Cimex lectularius
Bed bug
Acyrthosiphon pisum
Pea aphid
Zootermopsis nevadensis
Nevada dampwood termite
Orthologs in non-Insect Arthropods (via OrthoDB v9.1) ( EOG090X03O6 )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Strigamia maritima
European centipede
Ixodes scapularis
Black-legged tick
Stegodyphus mimosarum
African social velvet spider
Tetranychus urticae
Two-spotted spider mite
Daphnia pulex
Water flea
Orthologs in non-Arthropod Metazoa (via OrthoDB v9.1) ( EOG091G06FN )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus purpuratus
Purple sea urchin
Ciona intestinalis
Vase tunicate
Paralogs
Paralogs (via DIOPT v8.0)
Drosophila melanogaster (Fruit fly) (1)
6 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 ( 1 )
    Modifiers Based on Experimental Evidence ( 4 )
    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
    Show neighbor-neighbor interactions:
    Select Layout:
    Legend:
    Protein
    RNA
    Selected Interactor(s)
    Interactions Browser

    Please see the Physical Interaction reports below for full details
    RNA-protein
    Physical Interaction
    Assay
    References
    protein-protein
    Physical Interaction
    Assay
    References
    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
    Linkouts
    BioGRID - A database of protein and genetic interactions.
    DroID - A comprehensive database of gene and protein interactions.
    InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
    MIST (protein-protein) - An integrated Molecular Interaction Database
    Pathways
    Signaling Pathways (FlyBase)
    Metabolic Pathways
    KEGG Pathways - Wiring diagrams of molecular interactions, reactions and relations.
    Reactome - An open-source, open access, manually curated and peer-reviewed pathway database.
    External Data
    Linkouts
    Genomic Location and Detailed Mapping Data
    Chromosome (arm)
    X
    Recombination map

    1-63

    Cytogenetic map
    Sequence location
    X:19,667,252..19,672,353 [+]
    FlyBase Computed Cytological Location
    Cytogenetic map
    Evidence for location
    18D13-18D13
    Limits computationally determined from genome sequence between P{EP}Sec61γEP1511 and P{EP}EP1116&P{EP}EP1344EP1344
    Experimentally Determined Cytological Location
    Cytogenetic map
    Notes
    References
    18E-18E
    (determined by in situ hybridisation)
    18D12-18D13
    (determined by in situ hybridisation)
    18D-18D
    (determined by in situ hybridisation)
    Experimentally Determined Recombination Data
    Left of (cM)
    Right of (cM)
    Notes

    Mapped by T.R.F. Wright.

    Stocks and Reagents
    Stocks (17)
    Genomic Clones (8)
     

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

    cDNA Clones (35)
     

    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
    Other Comments

    Shows particularly robust cycling of transcription in adult heads, as assessed by expression analysis using high density oligonucleotide arrays with probe generated during three 12-point time course experiments over the course of 6 days. Shows significant change of expression pattern in circadian mutant background; decreased expression in per01, tim01 and ClkJrk background.

    Identified as a gene with significant level of mRNA cycling as assessed by expression analysis using high density oligonucleotide arrays with probe generated from adult heads harvested over six time points over the course of a day.

    Structure-function relationships based on studies of human G6PD deficiency-associated mutations predict that amino acids 382 and 384 fall within the protein domain responsible for NADP binding.

    Zw enzyme activity has been measured in D.melanogaster lines in which spontaneous mutations have accumulated over approximately 300 mutations.

    The effects of a high sucrose diet on live weight, total protein, stored lipid and glycogen and crude activities of 12 enzymes involved in energy metabolism are quantified. The activities of many enzymes are reduced by the sucrose treatment.

    Steroids slightly inhibit Zw activity but fail to inhibit Pgd activity.

    Addition of palmitoyl Co-A inhibits the activity of Zw gene product.

    At the DNA sequence level D.melanogaster populations from Zimbabwe are more than twice as variable as populations from U.S.A. Most variants are not shared between the two geographic regions and areas of low recombination rates have mutations that are nearly fixed.

    32 variants of Zw in D.melanogaster and 12 of G6pd in D.simulans have been compared: level of amino acid sequence divergence is 10-fold that expected under neutral model of evolution. Difference may be due to recent episodes of natural selection fixing advantageous amino acid mutations.

    Analysis of Zw promoter activation shows that one cis-acting region in P\Tcore and two such regions in P\TKP and P\TKP' elements are associated with activation, putative transcriptional regulatory proteins bind to each of the cis-acting regions. In vitro transcription analysis of P\T sequences activating Zw-Act5C transcriptional gene reveals three distinct cis-acting regions, one in P\Tcore and two in the P\TKP and P\TKP' elements, that are required for overexpression. Putative transcriptional regulatory proteins, identified in gel retardation assays, bind to each of the cis-acting regions.

    Gramoxone has no mutagenic effect on the genetic background of Zw.

    Pentose shunt flux studied.

    Insertion of a complex transposon carrying P\TKP, P\TKP' and P\Tcore into the 5' region of Zw does not alter the transcription start site or length of RNA transcripts but increases the amount of mRNA.

    The genomic DNA structure of Zw mutants and revertant strains has been determined in an attempt to obtain evidence that some mutants may be associated with the insertion of a transposable element.

    The effect of dietary sucrose and ethanol on Zw activity in the third larval instar has been studied.

    39 mutations at the Zw locus have been studied.

    The activity of G6PD is influenced by factors on the second and third chromosomes (Laurie-Alberg et al., 1980; Tanda and Hori, 1983; Miyashita et al., 1986). The suggestion of Giesel (1976) that Zw regulates structural genes on the autosomes has not been supported by studies of the mobility or activity of G6PD in D.melanogaster (Lucchesi, Hughes and Geer, 1979).

    Structural gene for glucose 6-phosphate dehydrogenase (Zwischenferment of Warburg) (G6PD), the first enzyme in the oxidative part of the pentose phosphate shunt. Electrophoretic variants ZwA and ZwB have been described in D.melanogaster (Young, Porter and Childs, 1964; Young, 1966). The G6PD produced by ZwA shows faster migration in starch gel (Young et al., 1964) by ZwB. A ZwA/ZwB female shows fast- and slow-migrating bands but no hybrid band of intermediate mobility (Young et al., 1964; Steele, Young and Childs, 1968; Hori and Tanda, 1980). The B variant in both homo- and heterozygotes is characterized by a double band and shows more heat stability than the A variant (Steele et al., 1968). A dominant sex-linked modifier of the electrophoretic mobility of G6PD, M(G6PD), has been described (Komma, 1968). A regulatory element that affects the activity level of G6PD has been reported (Itoh and Hori, 1985). The molecular weight of the A variant of G6PD approximates 147,000 and that of the B variant 317,000 according to Steele, Young and Childs (1968), who used the electrophoretic starch gel method and observed that the B form can dissociate and produce some A-like form. Lee et al. (1978), using gel-filtration chromatography, reported that the B variant has a molecular weight of 240,000. A subunit molecular weight for the purified enzyme was estimated by Lee, Langley and Burkhart (1978) to be 55,000 and by Hori and Tanda (1980) to be 69,000, as if the slow B variant represented a tetramer and the fast A variant a dimer of single polypeptides (Hori and Tanda, 1980; Miyashita et al., 1986). Significant amounts of the enzyme are found in the fat body and the intestine of D.melanogaster larvae (Cochrane and Lucchesi, 1980). Enzyme levels are raised by dietary sucrose or D-glycerate (Geer et al., 1976; Geer et al., 1978; Cavener and Clegg, 1981; Cochrane et al., 1983). A maternal form of G6PD can be detected up to the early pupal stage (Gerasimova and Smirnova, 1979). Total G6PD activity increases during the larval period, reaches a peak during the third larval instar, drops during pupation and increases again in the adult (Bijlsma and Van der Meulen-Bruijns, 1979; Williamson and Bentley, 1983). The enzyme shows a characteristic staining pattern in imaginal discs (Cunningham, Smith, Makowski and Kuhn, 1983). Males with one dose of Zw+ and females with two doses have about the same amount of G6PD activity, i.e. show dosage compensation for enzyme activity (Seecof, Kaplan and Futch, 1969; Gvozdev, Birstein, Polu-Karova and Kakpakov, 1971; Bowman and Simmons, 1973; Faizullin and Gvozdev, 1973; Williamson and Bentley, 1981). Females heterozygous for a Zw deficiency show a corresponding reduction in enzyme activity; males and females with an extra dose of Zw+ show increased enzyme activity (Seecof, Kaplan and Futch, 1969; Maroni and Plaut, 1973; Stewart and Merriam, 1975). Contribution of each dose of G6PD to the level of enzyme activity is the same in triploid females as in diploid females (Lucchesi and Rawls, 1973). A number of low- and null-activity mutations have been induced at the Zw locus. The mutant alleles are fully viable (Gvozdev, Gerasimova, Kogan and Braslavskaya, 1976; Hughes and Lucchesi, 1977; Bijlsma, 1980; Lucchesi, Hughes and Geer, 1979), but the larvae do not grow as well as wild type on a minimal amino-acid diet lacking fatty acids and whole nucleic acids (Geer, Bowman and Simmons, 1974). Null alleles at the ry locus are also viable, but double mutant combinations of Zw-;ry- do not survive (Lucchesi and Manning, 1988). Although Pgd- flies are lethal, Zw- Pgd- flies carrying null alleles for both G6PD, the first enzyme in the pentose phosphate shunt, and 6PGD, the last enzyme, are viable, presumably because the toxic 6-phosphogluconate is not produced (Hughes and Lucchesi, 1977; Hughes and Lucchesi, 1978; Geer, Lindel and Lindel, 1979; Lucchesi, Hughes and Geer, 1979). Many natural populations throughout the world are polymorphic for the A and B variants (Oakeshott, Chambers, Gibson, Eanes and Willcocks, 1983). Rare variants from a number of North American populations have been screened by sequential electrophoresis of starch and acrylamide gels to detect molecular heterogeneity (Eanes, 1983; Eanes, 1984; Eanes and Hey, 1986); the G6PD activity of these lines and also of induced mutants has been measured.

    Origin and Etymology
    Discoverer

    Young.

    Etymology
    Identification
    External Crossreferences and Linkouts ( 167 )
    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 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
    Drosophila Genomics Resource Center - Drosophila Genomics Resource Center (DGRC) cDNA clones
    Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
    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.
    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
    FLIGHT - Cell culture data for RNAi and other high-throughput technologies
    FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
    FlyCyc Genes - Genes from a BioCyc PGDB for Dmel
    FlyMine - An integrated database for Drosophila genomics
    InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
    KEGG Pathways - Wiring diagrams of molecular interactions, reactions and relations.
    MIST (protein-protein) - An integrated Molecular Interaction Database
    Reactome - An open-source, open access, manually curated and peer-reviewed pathway database.
    Synonyms and Secondary IDs (22)
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      References (300)