scholarly journals Analysis of autosomal dosage compensation involving the alcohol dehydrogenase locus in Drosophila melanogaster.

Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 677-686 ◽  
Author(s):  
J A Birchler ◽  
J C Hiebert ◽  
K Paigen

Abstract An example of autosomal dosage compensation involving the expression of the alcohol dehydrogenase (Adh) locus is described. Flies trisomic for a quarter of the length of the left arm of chromosome two, including Adh, have diploid levels of enzyme activity and alcohol dehydrogenase messenger RNA. Subdivision of the compensating trisomic into smaller ones revealed a region that exerts an inverse regulatory effect on alcohol dehydrogenase activity and messenger RNA levels and a smaller region surrounding the structural gene that exhibits a direct gene dosage response. The two opposing effects are of sufficient magnitude that they cancel when simultaneously present resulting in the observed compensation in the larger aneuploid. An Adh promoter-white structural gene fusion construct is affected by the inverse regulatory region indicating that the effect is mediated through the Adh promoter sequences. The role of autosomal dosage compensation in understanding aneuploid syndromes and karyotype evolution in Drosophila species is discussed.

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 625-637 ◽  
Author(s):  
James A Birchler

ABSTRACT The levels of alcohol dehydrogenase (ADH) do not exhibit a structural gene-dosage effect in a one to four dosage series of the long arm of chromosome one (1L) (BIRCHLER19 79). This phenomenon, termed dosage compensation, has been studied in more detail. Experiments are described in which individuals aneuploid for shorter segments were examined for the level of ADH in order to characterize the genetic nature of the compensation. The relative ADH expression in segmental trisomics and tetrasomics of region IL 0.72–0.90, which includes the Adh locus, approaches the level expected from a strict gene dosage effect. Region IL 0.20–0.72 produces a negative effect upon ADH in a similar manner to that observed with other enzyme levels when IL as a whole is varied (BIRCHLEF1I9 79). These and other comparisons have led to the concept that the compensation of ADH results from the cancellation of the structural gene effect by the negative aneuploid effect. The example of ADH is discussed as a model for certain other cases of dosage compensation in higher eukaryotes.


1975 ◽  
Vol 26 (1) ◽  
pp. 81-93 ◽  
Author(s):  
R. D. Ward

SUMMARYAlcohol dehydrogenase activity in Drosophila melanogaster may be considered as a quantitative character, since it shows many features typically associated with such traits. Although strains with the electrophoretically fast phenotype generally have activities greater than those with the slow phenotype, presumably reflecting differences in the nucleotide sequences of the structural alleles, within each electrophoretic class there is considerable variation in activity. The expression of the structural gene, in terms of ADH activity, is to some extent regulated by its genetic background. Strains homozygous for particular structural alleles respond to divergent directional selection for ADH activity. Modifiers have been located to the X, second and third chromosomes.


Genetics ◽  
1983 ◽  
Vol 103 (4) ◽  
pp. 649-658
Author(s):  
John H Williamson ◽  
Michael M Bentley

ABSTRACT The relationships between gene dosage, enzyme activities and CRM levels have been determined for G6PD and 6PGD. Enzyme activities and CRM levels were directly proportional and increased in genotypes carrying duplications of the respective structural genes. When a duplication consisting of the distal 45% of the X chromosome was used to duplicate Pgd  +, 6PGD activity and CRM increased and G6PD activity decreased. When the proximal 55% of the X chromosome was duplicated, G6PD activity and CRM increased whereas 6PGD activity and CRM levels decreased. These observations support the model of dosage compensation of X-linked genes that invokes an autosomal activator in limited concentrations for which X-linked loci compete. The distal 45% of the X chromosome, when duplicated, caused a significant increase in NADP-malic enzyme activity and CRM levels, as if a structural gene for NADP-ME is sex-linked.


Genetics ◽  
1973 ◽  
Vol 75 (4) ◽  
pp. 639-641
Author(s):  
Drew Schwartz

ABSTRACT The gene competition model, originally formulated from studies on the regulation of alcohol dehydrogenase activity in maize, is also applicable to the phenomenon of dosage compensation in Drosophila. The model accounts for the absence of dosage compensation in sex determination.


Tsitologiya ◽  
2018 ◽  
Vol 60 (6) ◽  
pp. 469-475
Author(s):  
O. D. Nimaeva ◽  
◽  
E. V. Pradedova ◽  
A. B. Karpova ◽  
R. K. Salyaev ◽  
...  

Nature ◽  
1974 ◽  
Vol 248 (5449) ◽  
pp. 564-567 ◽  
Author(s):  
John C. Lucchesi ◽  
John M. Rawls ◽  
Gustavo Maroni

1993 ◽  
Vol 4 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Giuseppe Borsani ◽  
Andrea Ballabio

1972 ◽  
Vol 42 (6) ◽  
pp. 781-784 ◽  
Author(s):  
Maureen O'keane ◽  
M. R. Moore ◽  
A. Goldberg

1. Because it has been shown that a majority of alcoholics are subclinically scorbutic, the metabolism of ethanol was studied in subclinically-scorbutic guinea-pigs. 2. Hepatic alcohol dehydrogenase activity was raised maximally by ethanol within 2 days. 3. In twenty-three subclinically-scorbutic guinea-pigs fed ethanol for 2 weeks, the alcohol dehydrogenase activity (±SD) was 11·5 ± 1·2 units/g of liver protein compared with 8·6 ± 0·6 units/g of liver protein in twenty-three healthy animals fed ethanol. 4. The NAD+/NADH ratio in subclinically-scorbutic guinea-pigs and healthy guinea-pigs fed ethanol, shows that there is more NAD+ available for oxidation of alcohol in subclinically-scorbutic guinea-pigs. These results may explain the increased tolerance of alcoholics to alcohol.


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