scholarly journals DOSAGE COMPENSATION IN DROSOPHILA: NADP-ENZYME ACTIVITIES AND CROSS-REACTING MATERIAL

Genetics ◽  
1983 ◽  
Vol 103 (4) ◽  
pp. 649-658
Author(s):  
John H Williamson ◽  
Michael M Bentley
Keyword(s):  
Enzyme Activity ◽  
Structural Gene ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Enzyme Activities ◽  
Malic Enzyme ◽  
Gene Dosage ◽  
G6pd Activity ◽  
Structural Genes ◽  
Malic Enzyme Activity

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.

scholarly journals SEGMENTAL ANEUPLOIDY AND ENZYME ACTIVITY AS A METHOD FOR CYTOGENETIC LOCALIZATION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1974 ◽  
Vol 76 (2) ◽  
pp. 301-309
Author(s):  
Barbara R Stewart ◽  
John R Merriam
Keyword(s):  
Enzyme Activity ◽  
X Chromosome ◽  
Gene Dosage ◽  
Chromosome Region ◽  
Structural Genes ◽  
The Third ◽  
Segmental Aneuploidy ◽  
Cytological Localization ◽  
The Relationship ◽  
Chromosome Bands

ABSTRACT A method of mapping genes which specify enzymes without the necessity of obtaining genetic variants has been explored. Three enzymes whose structural genes have known genetic positions were chosen to see if the relationship between gene dosage and enzyme activity could be used as a tool in cytological localization. Zw, the gene specifying G6PD, is located in the X chromosome region, 18D-18F. The structural gene for 6PGD, Pgd, maps in the X chromosome bands 2C1-2E1. Idh-NADP, the gene which specifies IDH-NADP, is found on the third chromosome, in bands 66B-67C.

scholarly journals Cardiac malic enzyme in Friedreich's disease

1984 ◽  
Vol 11 (S4) ◽  
pp. 643-645 ◽  
Author(s):  
A. Barbeau ◽  
M. Charbonneau ◽  
T. Cloutier ◽  
B. Lemieux
Keyword(s):  
Enzyme Activity ◽  
Enzyme Activities ◽  
Malic Enzyme ◽  
Control Subjects ◽  
Wide Variability ◽  
Malic Enzyme Activity ◽  
Mitochondrial Malic Enzyme

AbstractWe measured the activity of cytosolic and of mitochondrial malic enzyme in the hearts from 4 patients with Friedreich's disease and from two non-ataxic control subjects. There was a wide variability in the results and the slight overall decreases in both enzyme activities were not considered to be statistically significant. From these and other results, we conclude that deficient mitochondrial malic enzyme activity is not a constant or primary feature of Friedreich's disease.

Effect of gene dosage on expression of mitochondrial malic enzyme activity in the mouse

Nature ◽  
1978 ◽  
Vol 271 (5647) ◽  
pp. 748-750 ◽  
Author(s):  
EDWARD G. BERNSTINE ◽  
LIANE B. RUSSELL ◽  
CAROLYN S. CAIN
Keyword(s):  
Enzyme Activity ◽  
Malic Enzyme ◽  
Gene Dosage ◽  
Malic Enzyme Activity ◽  
Mitochondrial Malic Enzyme

scholarly journals INFLUENCE OF BACKGROUND GENOME ON ENZYMATIC CHARACTERISTICS OF YELLOW (Ay/-, Avy/-) MICE

Genetics ◽  
1973 ◽  
Vol 73 (1) ◽  
pp. 109-123
Author(s):  
George L Wolff ◽  
Henry C Pitot
Keyword(s):  
Enzyme Activity ◽  
Enzyme Activities ◽  
Malic Enzyme ◽  
Fat Metabolism ◽  
F1 Hybrids ◽  
F1 Hybrid ◽  
Serine Dehydratase ◽  
Cleavage Enzyme ◽  
Malic Enzyme Activity ◽  
Hybrid Mice

ABSTRACT dentification of the fundamental polypeptide difference between yellow (Ay/-, Avy/-) and non-yellow mice is important for biomedical research because of the influence of the yellow genotype on normal and neoplastic growth and obesity. The complexity of the "yellow mouse syndrome" makes attainment of this objective dependent on the separation of those pleiotropic enzyme differences which are secondary, and depend on the background genome, from those which are primary, and depend primarily on the agouti locus genotype.—Four of nine hepatic enzyme activities assayed simultaneously differed between eight-week-old yellow (Ay/-, Avy/-) and non-yellow (A/-, a/a) male inbred and F1 hybrid mice. Among these four, only cytoplasmic malic enzyme activity was elevated in all yellow mice, as compared with the non-yellow sibs, regardless of background genome. Glucokinase, serine dehydratase, and tyrosine α-ketoglutarate transaminase activities were also changed in yellow mice, but these alterations depended on the background genome.—The ratio of malic enzyme activity to citrate-cleavage enzyme activity, possibly related to the altered fat metabolism of yellow mice, was influenced by background genome as well as by the yellow genotype.—Significant deviations of enzyme activities from mid-parent values among F1 hybrids were associated with particular background genomes; the number of such deviations was larger among yellow mice than among non-yellows and this difference was greater among C3H F1 hybrids than among C57BL/6 F1 hybrids.

Morphological and biochemical analyses of changes in rat hepatocytes related to wine and ethanol consumption

1984 ◽  
Vol 42 ◽  
pp. 232-233
Author(s):  
S.M. Geyer ◽  
C.L. Mendenhall ◽  
J.T. Hung ◽  
E.L. Cardell ◽  
R.L. Drake ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Enzyme Activity ◽  
Malic Enzyme ◽  
Smooth Endoplasmic Reticulum ◽  
Rat Hepatocytes ◽  
Mature Male ◽  
Treatment Groups ◽  
Malic Enzyme Activity ◽  
Biochemical Analyses

Thirty-three mature male Holtzman rats were randomly placed in 3 treatment groups: Controls (C); Ethanolics (E); and Wine drinkers (W). The animals were fed synthetic diets (Lieber type) with ethanol or wine substituted isocalorically for carbohydrates in the diet of E and W groups, respectively. W received a volume of wine which provided the same gram quantity of alcohol consumed by E. The animals were sacrificed by decapitation after 6 weeks and the livers processed for quantitative triglycerides (T3), proteins, malic enzyme activity (MEA), light microscopy (LM) and electron microscopy (EM). Morphometric analysis of randomly selected LM and EM micrographs was performed to determine organellar changes in centrilobular (CV) and periportal (PV) regions of the liver. This analysis (Table 1) showed that hepatocytes from E were larger than those in C and W groups. Smooth endoplasmic reticulum decreased in E and increased in W compared to C values.

‘Malic Enzyme’ Activity in Blowfly Muscle

Nature ◽  
1956 ◽  
Vol 177 (4514) ◽  
pp. 842-843 ◽  
Author(s):  
S. E. LEWIS ◽  
G. M. PRICE
Keyword(s):  
Enzyme Activity ◽  
Malic Enzyme ◽  
Malic Enzyme Activity

An in situ cell marker for clonal analysis of development of the extraembryonic endoderm in the mouse*

Development ◽  
1984 ◽  
Vol 80 (1) ◽  
pp. 251-288
Author(s):  
R. L. Gardner
Keyword(s):  
Enzyme Activity ◽  
Malic Enzyme ◽  
Cell Mass ◽  
Differential Staining ◽  
Wild Type ◽  
Primitive Endoderm ◽  
Extraembryonic Endoderm ◽  
Blue Tetrazolium ◽  
Malic Enzyme Activity ◽  
Parietal Endoderm

Conditions were found for staining whole mid-gestation capsular parietal endoderms and visceral yolk sacs for malic enzyme activity that gave excellent discrimination between wildtype (Mod-1+/Mod-1+) cells and mutant (Mod-ln/Mod-1n) cells that lack the cytoplasmic form of the enzyme. Reciprocal blastocyst injection experiments were undertaken in which single primitive endoderm cells of one genotype were transplanted into embryos of the other genotype. In addition, Mod-1+/Mod-1+ early inner cell mass (ICM) cells were injected into Mod-1n/Mod-1n blastocysts, either in groups of two or three singletons or as daughter cell pairs. A substantial proportion of the resulting conceptuses showed mosaic histochemical staining in the parietal endoderm, visceral yolk sac, or in both these membranes. Stained cells were invariably intimately intermixed with unstained cells in the mosaic parietal endoderms. In contrast, one or both of two distinct patterns of staining could be discerned in mosaic visceral yolk sacs. The first, a conspicuously ‘coherent’ pattern, was found to be due to endodermal chimaerism; the second, a more diffuse pattern, was attributable to chimaerism in the mesodermal layer of this membrane. The overall distribution of cells with donor staining characteristics resulting from primitive endoderm versus early ICM cell injections was consistent with findings in earlier experiments in which allozymes of glucosephosphate isomerase were used as markers. The conspicuous lack of phenotypically intermediate cells in predominantly stained areas of mosaic membranes suggested that the histochemical difference between Mod-1+/Mod-1+ and Mod-1n/Mod-ln genotypes was cell-autonomous. This conclusion was strengthened by the results of staining mixed in vitro cultures of parietal endoderm in which presence or absence of phagocytosed melanin granules was used as an independent means of distinguishing wild type from null cells. By substituting tetranitro blue tetrazolium for nitro blue tetrazolium in the incubation medium, satisfactory differential staining was obtained for both the extraembryonic endoderm and other tissues of earlier postimplantation wild type versus null embryos. Finally, absence of cytoplasmic malic enzyme activity does not appear to have a significant effect on the viability or behaviour of mutant cells.

X chromosome gene dosage compensation in female mammals

1993 ◽  
Vol 4 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Giuseppe Borsani ◽  
Andrea Ballabio
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Gene Dosage ◽  
Chromosome Gene

scholarly journals On the Mode of Gene-Dosage Compensation in Drosophila

Genetics ◽  
1997 ◽  
Vol 145 (3) ◽  
pp. 729-736
Author(s):  
Irina Arkhipova ◽  
Jingjing Li ◽  
Matthew Meselson
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Gene Dosage ◽  
Gene Activity ◽  
Gene Copy ◽  
Drosophila Pseudoobscura ◽  
A Site ◽  
Reduced Activity ◽  
Per Gene

A procedure is described for determining the mode and magnitude of gene-dosage compensation of transformed genes. It involves measurement of the ratio of the activity of a gene inserted at X-linked sites to the activity of the same gene inserted at autosomal sites. Applying the procedure to the Drosophila pseudoobscura Hsp82 gene inserted at ectopic sites in D. melanogaster and taking gene activity as proportional to the amount of transcript per gene copy, we conclude that (1) in both adults and larvae the gene is not compensated at autosomal sites or at a site in β-heterochromatin at the base of the X chromosome and is fully compensated at euchromatic X-chromosomal sites; (2) inappropriate normalization is responsible for a claim that the gene is compensated at autosomal sites; and (3) the observed compensation operates mainly or entirely by heightened activity of X-linked genes in males, rather than by reduced activity in females.

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