Partial Correction of Structural Defects in Alcohol Dehydrogenase through Interallelic Complementation in Drosophila melanogaster

Alcohol dehydrogenases (ADH) from the F₁ progeny of all pairwise crosses between 12 null-activity mutants and crosses between these mutants and four active variants, ADHⁿ⁵ ADH^F, ADH^D and ADH^S, were analyzed for the presence of active or inactive heterodimers. Gels were stained for ADH enzyme activity, and protein blots of duplicate gels were probed with ADH-specific antibody to detect cross-reacting material. Crosses between the three major electrophoretic variants. ADH^F, ADH^S and ADH^D, all produced active heterodimers. Four mutant proteins (ADHⁿ², ADHⁿ⁴, ADHⁿ¹⁰ and ADHⁿ¹³) did not form heterodimers with any other ADH subunit tested. Of the 28 crosses involving the remaining null activity mutants, 22 produce heterodimers. Twelve of these exhibit partial restoration of enzyme activity. In five cases of active heterodimers from null-activity crosses, Adhⁿ¹¹ supplied one of the subunits. In two crosses involving the active variant ADH^D, the null activity mutant subunits (ADHⁿ⁸ and ADHⁿ³) destabilized the heterodimer sufficiently to cause inactivation of the ADH^D subunit. In the cross between Adh^F and Adhⁿ³, the activity of the ADH^F subunit was also greatly reduced in association with the ADHⁿ³ subunit. Two crosses (Adhⁿ¹ x Adhⁿ¹¹ and Adhⁿ⁵ x Adhⁿ¹²) result in partial restoration of one of the homodimeric proteins (ADH ⁿ¹ and ADHⁿ¹², respectively), as well as forming active heterodimers.     

Molecular analysis of Drosophila melanogaster AdhnLA405 confirms reliability of DNA-sequencing methodology

An alcohol dehydrogenase (ADH) null mutant of Drosophila melanogaster (AdhnLA405) originally recovered following X-ray irradiation of mature sperm (Aaron, 979) is analyzed by Southern blotting, Western blotting, and DNA sequencing. The genetic, immunologic, and nucleic acid sequence data are consistent with the hypothesis that a cross-over event, independent of X-irradiation, between parental chromosomes is responsible for the ADH null phenotype of AdhnLA405. By DNA-sequence analysis we show that molecular cloning of this locus (i.e., propagation in prokaryotic hosts) apparently does not introduce any spurious changes (substitutions, additions, deletions, or rearrangements) within the DNA.     

Alcohol dehydrogenase (ADH) isozymes in the AdhN/AdhN strain ofPeromyscus maniculatus (ADH− deermouse) and a possible role of class III ADH in alcohol metabolism

Although the Adh^N/Adh^N strain ofPeromyscus maniculatus (so-called ADH^? deermouse) has been previously considered to be deficient in ADH, we found ADH isozymes of Classes II and III but not Class I in the liver of this strain. On the other hand, the Adh^F/Adh^F strain (so-called ADH⁺ deermouse), which has liver ADH activity, had Class I and III but not Class II ADH in the liver. In the stomach, Class III and IV ADHs were detected in both deermouse strains, as well as in the ddY mouse, which has the normal mammalian ADH system with four classes of ADH. These ADH isozymes were identified as electrophoretic phenotypes on the basis of their substrate specificity, pyrazole sensitivity, and immunoreactivity. Liver ADH activity of the ADH^? strain was barely detectable in a conventional ADH assay using 15 mM ethanol as substrate; however, it increased markedly with high concentrations of ethanol (up to 3M) or hexenol (7 mM). Furthermore, in a hydrophobic reaction medium containing 1.0M t-butanol, liver ADH activity of this strain at low concentrations of ethanol (<100 mM) greatly increased (about sevenfold), to more than 50% that of ADH⁺ deermouse. These results were attributable to the presence of Class III ADH and the absence of Class I ADH in the liver of ADH^? deermouse. It was also found that even the ADH⁺ strain has low liver ADH activity (<40% that of the ddY mouse) with 15 mM ethanol as substrate, probably due to low activity in Class I ADH. Consequently, liver ADH activity of this strain was lower than its stomach ADH activity, in contrast with the ddY mouse, whose ADH activity was much higher in the liver than in the stomach, as well as other mammals. Thus, the ADH systems in both ADH^? and ADH⁺ deermouse were different not only from each other but also from that in the ddY mouse; the ADH^? strain was deficient in only Class I ADH, and the ADH⁺ strain was deficient in Class II ADH and down-regulated in Class I ADH activity. Therefore, Class III ADH, which was found in both strains and activated allosterically, may participate in alcohol metabolism in deermouse, especially in the ADH^? strain.     

Variation in alcohol dehydrogenase activity in vitro in flies from natural populations ofDrosophila melanogaster

Alcohol dehydrogenase (ADH) activity variation in male flies taken directly from seven natural populations ofDrosophila melanogaster is largely accounted for by segregation of alleles at theAdh structural gene locus. There was little overlap in the ADH activities ofAdh ^F andAdh ^s homozygotes. Body weights varied only slightly betweenAdh genotypes and contributed little to ADH variation. Between and within population variation in ADH activity and ADH protein in flies in the wild is mainly due to the relative frequencies ofAdh ^F andAdh ^s.     

Cloning and sequence analysis of genes involved in erythromycin biosynthesis in Saccharopolyspora erythraea: sequence similarities between EryG and a family of S-adenosylmethionine-dependent methyltransferases.

Summary Treatment of tomato seeds with ethyl methanesulphonate (EMS) followed by allyl alcohol selection of M₂ seeds has led to the identification of one plant (B15-1) heterozygous for an alcohol dehydrogenase (Adh) null mutation. Genetic analysis and expression studies indicated that the mutation corresponded to the structural gene of the Adh-1 locus on chromosome 4. Homozygous Adh-1 null mutants lacked ADH-1 activity in both pollen and seeds. Using an antiserum directed against ADH from Arabidopsis thaliana, which crossreacts with ADH-1 and ADH-2 proteins from tomato, no ADH-1 protein was detected in seeds of the null mutant. Northern blot analysis showed that Adh-1 mRNA was synthesized at wild-type levels in immature seeds of the null mutant, but dropped to 25% in mature seeds. Expression of the Adh-2 gene on chromosome 6 was unaffected. The potential use of the Adh-1 null mutant in selecting rare transposon insertion mutations in a cross with mutable Adh-1 ⁺ tomato lines is discussed.     

Genetic Control of Adh Expression in DROSOPHILA MELANOGASTER

Natural variants displaying different levels of expression of the gene for alcohol dehydrogenase (Adh) were subjected to genetic mapping experiments. The strains studied carry one of the two common electrophoretic forms of the enzyme. The difference among Adh-fast strains appears to be due to multiple loci with trans-acting effects. Differences among Adh-slow strains are due to modifiers or quantitative sites located very close to the structural gene (less than 0.05 map unit) or part of it. The modifiers detected in the Adh^s strains seem to operate only on the structural allele in the cis-position.—A modifier that affects the ratio of ADH levels in larvae and adults was also detected in the Adh^s strains. This modifier is also closely linked to Adh and is cis-acting.     

Dimerization of multiple maize ADHs studied in vivo and in vitro

Anaerobically induced primary roots simultaneously express two alcohol dehydrogenase (Adh) genes which specify three types of electrophoretically separable dimers: Set I, II, and III ADH. The S inbred line yields a particular activity ratio among these three sets. By use of an Adh ₁ ^null mutant allele and in vitro chemical dissociation and reassociation of ADH dimers, these studies extrapolate from an ADH activity ratio to the actual ratio of ADH protein. Conclusions are that (1) ADH₁ and ADH₂ promoters dimerize randomly in vivo and in vitro, (2) the heterodimeric isozyme (Set II) is approximately the enzymological sum of its subunits under these assay conditions, and (3) ADH-2 subunits are from 10 to 20% as active as ADH₁ subunits under these assay conditions. These conclusions imply that the unlinked Adh genes are coordinately regulated and reconfirm the two-gene-three-dimer model for the maize ADH isozymes.     

Polymorphism of alcohol dehydrogenase in Arabidopsis thaliana (L.) heynh.: Genetical and biochemical characterization

Zymograms of Arabidopsis alcohol dehydrogenase (ADH; EC 1.1.1.1) show a unique anodal migrating band. Three electrophoretic variants were identified among geographical races and designated slow (S), fast (F), and superfast (A), according to their mobility on Tris-citrate starch gels. In plants ADH activity is confined mainly to pollen, seeds, and grains and rapidly declines during the germination process. In callus and suspension cultures, growing on media containing 2,4-D, ADH appeared as one of the major polypeptides. Genetical analysis indicated that the three types of ADH isozymes are under the control of one gene with three alles (Adh ₁ ^s , Adh ₁ ^f , Adh ₁ ^a ), showing codominant expression. Crosses between the electrophoretic types and dissociation-reassociation experiments showed that the Arabidopsis enzyme behaves as a dimer, like ADH from most other species. The molecular weight of the enzyme has been estimated by gel filtration and by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis to be 87,000. The pH optimum for the oxidation of ethanol is 9.0 and two optima for reduction of acetaldehyde have been obtained, 6.0 and 8.5, respectively. The enzyme exhibits a wide substrate specificity for alcohols and is relatively heat resistant.     

Genetic regulation of liver alcohol dehydrogenase in Peromyscus

Data from genetic crosses of Peromyscus maniculatus and P. polionotus suggest that electrophoretic variants of liver alcohol dehydrogenase are coded by alleles at a single locus. These alleles, designated Adh ^F , Adh ^S , and Adh ^N , determine, respectively, the fast, slow, and not detectable (null) ADH electrophoretic phenotypes. Heterozygotes (Adh ^F /Adh ^S ) exhibit three bands on zymograms, suggesting a dimeric subunit structure for the enzyme. However, Adh ^F /Adh ^N and Adh ^S /Adh ^N animals exhibit a single band, suggesting that the Adh ^N allele does not produce a polypeptide subunit capable of dimerizing into an active molecule. Fast and slow electrophoretic phenotypes exhibit multiple bands which can be converted into single major fast and slow bands, respectively, upon treatment with oxidized or reduced NAD. Addition of NAD also stabilizes both the fast and slow enzyme to heat inactivation at 60 C for at least 30 min.This work was supported by Predoctoral Fellowship AA-05067 from the National Institute of Alcohol Abuse and Alcoholism to K. G. B. and South Carolina Commission on Alcohol and Drug Abuse Grant 7607. Also, partial support was provided by NIH Grant CA-16184.     

The <Emphasis Type="Italic">Adh</Emphasis> locus and adaptation of <Emphasis Type="Italic">cn</Emphasis> and <Emphasis Type="Italic">vg</Emphasis> mutants in experimental populations of <Emphasis Type="Italic">Drosophila melanogaster MEIG</Emphasis>

A complex study on the adaptation of cn and vn mutants and the allozymes of alcoholdehydrogenase (ADH) was carried out in initially pure lines, and their panmixia populations during exchange of the mutant genotype with that of wild-type flies (C-S) and D) through saturating crossings. The relative adaptation of the genotypes was estimated by their effect on reproductive efficiency in the experimentally obtained population. Fecundity, lifespan, and the resistance of the studied genotypes to hyperthermia were investigated individually. It was shown that the high level of adaptation of the cn mutants and the low level of adaptation of the vg mutants was correlated with the presence of different ADH allozymes. In the studied population, the F-allozyme of ADH accompanied the vg mutation, while the S-allozyme of the enzyme was detected in cn mutants. Saturating crossings of C-S(Adh ^S)×vg(Adh ^F) and D(Adh ^F) × cn(Adh ^S), along with the parallel determination of the allele composition of the Adh locus, demonstrated that the complete substitution of the F-allozyme of ADH in the vg mutants by the S-allozyme in D flies, as well as the substitution of the S-allozyme of ADH in the cn mutants by the F-allozyme in D flies was realized only after the 15th–20th backcrosses. These results favor the coadaptation of cn and vg marker genes with alleles of the Adh locus and indicate the important role of the latter in the adaptation of genotypes. In the studied population, selection acted primarily against the vg mutants, which were inferior to the cn mutants, and heterozygote genotypes in indices of the main adaptation components.     

Adaptive significance of the action of the Drosophila melanogaster alcohol dehydrogenase locus through the heat shock protein system

Four Drosophila melanogaster strains, each homozygous for one of the two major ADH aliozymes, Fast and Slow (Adh ^F1, Adh ^S , Adh ^F2 and Adh ^S2) were used to study the interaction of the Adh locus with ethanol and temperature. The separate and especially the combined effects of these two parameters allow the conclusion that the Adh locus of D. melanogaster intervenes in the adaptation process through the heat shock protein system.     

Alcohol dehydrogenase polymorphism in populations of Drosophila melanogaster. II. Relation between ADH activity and adult mortality

Eight Drosophila melanogaster strains, seven homozygous for Adh ^F alleles and one for an Adh-null mutant, were compared for ADH activity in males and adult mortality on ethanol-supplemented food. The strains differed considerably in these qualities. A positive correlation was found between ADH activity and ld ₅₀. The relevance of this finding is discussed in relation to the differential selection acting on Adh genotypes kept on ethanol-supplemented food.     

beta-Amylase from Mustard (Sinapis alba L.) Cotyledons : Immunochemical Evidence for Synthesis de Novo during Photoregulated Seedling Development

In barley (Hordeum vulgare L.), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) are induced by anaerobiosis in both aleurone layers and roots. Under aerobic conditions, developing seeds of cv Himalaya accumulate ADH activity, which survives seed drying and rehydration. This activity consists almost entirely of the ADH1 homodimer. Activity of LDH also increases during seed development, but the level of activity in dry or rehydrated seeds is very low, indicating that this enzyme may not be involved in anaerobic glycolysis during the initial stages of germination. In contrast to ADH, the LDH isozymes present in developing seeds are similar to those found in uninduced and induced roots. Developmental expression of ADH and LDH was monitored from 0 to 24 days postgermination. Neither activity was induced to any extent in the germinating seeds; however, both enzymes were highly induced by anoxia in root tissue during development. Based on gel electrophoresis, this increase in activity results from the differential expression of different Adh and Ldh genes in root tissue. The changes in ADH and LDH activity levels were matched by changes in the amount of these particular proteins, indicating that the increase in activity results from de novo synthesis of these two proteins. The level of inducible LDH activity in an ADH1⁻ mutant was not found to differ from cv Himalaya. We suggest that although the ADH⁻ plants are more susceptible to flooding, they are not capable of responding to the lack of ADH1 activity by increasing the amount of LDH activity in root tissue.     

Isozyme variability in species of the genus Drosophila. VI. Frequency-property-environment relationships of allelic alcohol dehydrogenases in D. melanogaster

Adult Drosophila melanogaster from naturally occurring populations in the Eastern United States were examined by gel electrophoresis for their alcohol dehydrogenase (ADH) phenotype. The ADH enzymes were partially purified and characterized. Frequencies of the controlling alleles, Adh ⁴ and Adh ⁶, were discovered to vary in a clinal pattern. Adh ⁶ reaches a maximum frequency of about 0.90 in the South and minimum of about 0.50 in the North. Partially purified enzymes from the three Adh genotypes varied according to specific activity, substrate specificity, and heat stability. A differential influence of pH was indicated. There was little variation in K _m values for ethanol and DPN⁺ among the enzymes.This work was supported by AEC Contract No. AT-(40-1)-3980 and by PHS Research Grant No. GM 11546.Paper No. 3880 of the Journal Series of the North Carolina Experiment Station, Raleigh, North Carolina. This work incorporates, in part, the thesis research of C. L. Vigue to be submitted in partial fulfillment of the Ph.D. requirements in Genetics.     

Simultaneous induction by anaerobiosis or 2,4-D of multiple enzymes specificed by two unlinked genes: differential Adh1-Adh2 expression in maize

Summary The data of this paper partially define a two-gene, differentially inducible enzyme system in maize. Four major conclusions are drawn. (1) Anaerobic treatment results in the simultaneous expression of two unlinked Adh genes, Adh1 and Adh2. Adh2 is scarcely expressed in the uninduced root and negligibly expressed in the quiescent embryo. (2) The zero-order rate of anaerobic ADH protein induction reflects the zero-order rate of ADH synthesis throughout the induction; all active ADH isozymes display negligible turnover during the induction. (3) The auxin, 2,4-D, overcomes repression by air. The aerobic induction rates are also zero-order with negligible turnover for any isozyme. (4) The ratio of Adh1-Adh2 expression is drastically altered dependent on the mode of induction. The level of this differential regulatory phenomenon is before or at the assembly of ADH polypeptides into enzymologically or antigenically active dimers.     

Association and the Adh locus with a lethal factor (l(2) Stm) in Drosophila melanogaster

Keeping Drosophila cultures at 28 C results in elimination of all minor multiple ADH bands, thought to be due to conformational change. Thus in diploid and triploid adults heterozygous for the Adh ^F and Adh ^Salleles, relative staining intensities are found for the three bands which were in conformity with the assumption that both alleles are equally expressed. Among all polymorphic strains derived from natural Central European and Mediterranean populations, the strain ⁺Tüb is unique in that its Adh ^Fallele is closely linked to a new recessive lethal factor, named 1(2)Stm. All Adh ^F 1/Adh^F 1 pupae are unable to emerge, and die. The lethal effect is obvious 50 hr earlier by retarded eye, bristle, and body wall pigmentation. Although all pupae of the phenotype F die, Adh ^F allele frequency scarcely seems to be lowered in this natural population.     

Dissociation-recombination of intergenic sunflower alcohol dehydrogenase isozymes and relative isozyme activities

Two unlinked genes, Adh ₁ and Adh ₂, control the production of alcohol dehydrogenase (ADH) in seeds of the annual sunflower (Helianthus annuus). Each gene is polymorphic, having F and S alleles. Starch gel electrophoretic zymograms of the four possible double homozygotes have three bands, representing two homodimers and an intermediately migrating intergenic isozyme. Zymograms of double heterozygotes consist of nine bands produced by ten isozymes: six intragenics and four intergenics, two of which are coincident. Results of dissociation-recombination (D-R) experiments are reported which demonstrate the subunit composition of the intergenic isozymes, thus supporting the relationships suggested by genetic studies. Densitometric tracings of the zymogram of a cleared gel and measurements of activities of homodimer isozymes eluted from gels following D-R of an intergenic isozyme showed that the Adh ₂ isozymes were more than twice as active as those of Adh ₁. Measurements of activities of crude extracts from the four possible double homozygous genotypes indicated that the seeds of the genotype Adh ₁ ^F /Adh ₁ ^F , Adh ₂ ^S /Adh ₂ ^S produced more activity than the other three. This genotype is the most common one found in wild and cultivated stocks. Isozymes eluted following electrophoresis of the same extracts had averages of 19%, 70%, and 11% of total activity contributed by the Adh ₁, Adh₂, and intergenic isozymes, respectively. A simple but efficient method of isozyme elution from starch gels is described which resulted in nearly full expected recovery (approximately 46%) of the ADH activity in the applied sample.Supported by Graduate School and BioMed grants and by NSF Grant GB35853.