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 Clk^Jrk 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\T^core and two such regions in P\T^KP and P\T^KP' 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\T^core and two in the P\T^KP and P\T^KP' 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\T^KP, P\T^KP' and P\T^core 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 Zw^A and Zw^B have been described in D.melanogaster (Young, Porter and Childs, 1964; Young, 1966). The G6PD produced by Zw^A shows faster migration in starch gel (Young et al., 1964) by Zw^B. A Zw^A/Zw^B 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.