scholarly journals DOSAGE COMPENSATION IN DROSOPHILA MELANOGASTER TRIPLOIDS. II. GLUCOSE-6-PHOSPHATE DEHYDROGENASE ACTIVITY

Genetics ◽  
1973 ◽  
Vol 74 (2) ◽  
pp. 331-342
Author(s):  
Gustavo Maroni ◽  
Walter Plaut
Keyword(s):  
Enzyme Activity ◽  
Dosage Compensation ◽  
Live Weight ◽  
Regulatory Mechanisms ◽  
Special Device ◽  
Regulatory Factor ◽  
X Chromosomes ◽  
Integral Number ◽  
Level Of Activity ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT The level of activity of the enzyme glucose-6-phosphate dehydrogenase was determinel in flies having seven different chromosomic constitutions. All those having an integral number of chromosomes [XAA, XXAA, XAAA, XXAAA, and XXXAAA (X=X chromosome, A=set of autosomes)] were found to have similar units of enzyme activity/mg live weight, while diploid females with a duplication and triploid females with a deficiency showed dosage effect. The amount of enzyme activity per cell, on the other hand, is also independent of the number of X's present but appears roughly proportional to the number of sets of autosomes.—It is proposed that dosage-compensated sex-linked genes are controlled by a positively acting regulatory factor(s) of autosomal origin. With this hypothesis it is possible to explain dosage compensation as a consequence of general regulatory mechanisms without invoking a special device which applies only to the X chromosomes.

scholarly journals Absence of X-chromosome dosage compensation in the primordial germ cells of Drosophila embryos

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryoma Ota ◽  
Makoto Hayashi ◽  
Shumpei Morita ◽  
Hiroki Miura ◽  
Satoru Kobayashi
Keyword(s):  
X Chromosome ◽  
Germ Cells ◽  
Dosage Compensation ◽  
Sex Chromosome ◽  
Primordial Germ Cells ◽  
Histone H4 ◽  
X Chromosomes ◽  
Essential Components ◽  
Msl Complex ◽  
Male Specific

AbstractDosage compensation is a mechanism that equalizes sex chromosome gene expression between the sexes. In Drosophila, individuals with two X chromosomes (XX) become female, whereas males have one X chromosome (XY). In males, dosage compensation of the X chromosome in the soma is achieved by five proteins and two non-coding RNAs, which assemble into the male-specific lethal (MSL) complex to upregulate X-linked genes twofold. By contrast, it remains unclear whether dosage compensation occurs in the germline. To address this issue, we performed transcriptome analysis of male and female primordial germ cells (PGCs). We found that the expression levels of X-linked genes were approximately twofold higher in female PGCs than in male PGCs. Acetylation of lysine residue 16 on histone H4 (H4K16ac), which is catalyzed by the MSL complex, was undetectable in these cells. In male PGCs, hyperactivation of X-linked genes and H4K16ac were induced by overexpression of the essential components of the MSL complex, which were expressed at very low levels in PGCs. Together, these findings indicate that failure of MSL complex formation results in the absence of X-chromosome dosage compensation in male PGCs.

scholarly journals Contingency in the convergent evolution of a regulatory network: Dosage compensation in Drosophila

2018 ◽  
Author(s):  
Doris Bachtrog ◽  
Chris Ellison
Keyword(s):  
Transposable Element ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Binding Sites ◽  
Evolutionary Biology ◽  
De Novo ◽  
Binding Motif ◽  
Sequence Motif ◽  
X Chromosomes ◽  
Msl Complex

The repeatability or predictability of evolution is a central question in evolutionary biology, and most often addressed in experimental evolution studies. Here, we infer how genetically heterogeneous natural systems acquire the same molecular changes, to address how genomic background affects adaptation in natural populations. In particular, we take advantage of independently formed neo-sex chromosomes in Drosophila species that have evolved dosage compensation by co-opting the dosage compensation (MSL) complex, to study the mutational paths that have led to the acquisition of 100s of novel binding sites for the MSL complex in different species. This complex recognizes a conserved 21-bp GA-rich sequence motif that is enriched on the X chromosome, and newly formed X chromosomes recruit the MSL complex by de novo acquisition of this binding motif. We identify recently formed sex chromosomes in the Drosophila repleta and robusta species groups by genome sequencing, and generate genomic occupancy maps of the MSL complex to infer the location of novel binding sites. We find that diverse mutational paths were utilized in each species to evolve 100s of de novo binding motifs along the neo-X, including expansions of microsatellites and transposable element insertions. However, the propensity to utilize a particular mutational path differs between independently formed X chromosomes, and appears to be contingent on genomic properties of that species, such as simple repeat or transposable element density. This establishes the “genomic environment” as an important determinant in predicting the outcome of evolutionary adaptations.

scholarly journals Parallel Universes for Models of X Chromosome Dosage Compensation in Drosophila: A Review

2016 ◽  
Vol 148 (1) ◽  
pp. 52-67 ◽  
Author(s):  
James A. Birchler
Keyword(s):  
X Chromosome ◽  
Dosage Compensation ◽  
Sex Chromosome ◽  
Fold Increase ◽  
Molecular Data ◽  
X Chromosomes ◽  
Histone Modifiers ◽  
Parallel Universes ◽  
Msl Complex ◽  
High Level

Dosage compensation in Drosophila involves an approximately 2-fold increase in expression of the single X chromosome in males compared to the per gene expression in females with 2 X chromosomes. Two models have been considered for an explanation. One proposes that the male-specific lethal (MSL) complex that is associated with the male X chromosome brings histone modifiers to the sex chromosome to increase its expression. The other proposes that the inverse effect which results from genomic imbalance would tend to upregulate the genome approximately 2-fold, but the MSL complex sequesters histone modifiers from the autosomes to the X to mute this autosomal male-biased expression. On the X, the MSL complex must override the high level of resulting histone modifications to prevent overcompensation of the X chromosome. Each model is evaluated in terms of fitting classical genetic and recent molecular data. Potential paths toward resolving the models are suggested.

CYCLISCHE SCHWANKUNGEN DER AKTIVITÄTEN VON HYDROXYSTEROID-DEHYDROGENASEN IM CORPUS LUTEUM DES RINDES

1972 ◽  
Vol 69 (2) ◽  
pp. 369-384
Author(s):  
H. Brandau ◽  
L. Brandau ◽  
G. Mutzke
Keyword(s):  
Enzyme Activity ◽  
Corpus Luteum ◽  
Enzyme Activities ◽  
Optical Method ◽  
Activity Patterns ◽  
Hydroxysteroid Dehydrogenase ◽  
Corpora Lutea ◽  
Bovine Corpus Luteum ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT In the bovine corpora lutea periodical activities of the Δ53β-, 3β-, 17β-and 20β-hydroxysteroid dehydrogenase (OHSDH) as well as activities of glyceraldehyde-3-phosphate- and glucose-6-phosphate dehydrogenase were measured quantitatively and the alterations throughout the different stages of the cycle were studied. After homogenization of the tissue and fractionate centrifugation the enzyme activities were determined by a standardized optical method. The activities of the Δ53β-, and 3β- and 17β-OHSDH increase slowly during the first 7 days of the cycle, the maximum is reached abruptly on the 12th to 13th day of the cycle. After a striking reduction the activities decline continually to the 19th to 21st day reaching the values detected at the beginning of the cycle. The 20β-OHSDH increases slowly to the maximum on the 15th day of the cycle. Activities of the 3α-OHSDH were obtained only inconsistently. The behaviour of the activities of G6PDH was nearly identical with that of the 3β-OHSDH, while the GAPDH shows only little fluctuations of its activities. The obtained enzyme activity patterns of the maturating and high functional corpus luteum correspond to the well-known data of the biosynthetic function of the bovine corpus luteum. The changes of the amounts of progesterone and 20β-progesterol agree with the course of the activities of the 3β- resp. 20β-OHSDH.

SDC-3 coordinates the assembly of a dosage compensation complex on the nematode X chromosome

Development ◽  
1997 ◽  
Vol 124 (5) ◽  
pp. 1019-1031 ◽  
Author(s):  
T.L. Davis ◽  
B.J. Meyer
Keyword(s):  
Zinc Finger ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Protein Complex ◽  
Terminal Region ◽  
X Chromosomes ◽  
C Elegans ◽  
Amino Terminal ◽  
Zinc Finger Motifs ◽  
Specific Association

X chromosome expression in C. elegans is controlled by a chromosome-wide regulatory process called dosage compensation that specifically reduces by half the level of transcripts made from each hermaphrodite X chromosome. This process equalizes X expression between the sexes (XX hermaphrodites and XO males), despite their two-fold difference in X chromosome dose, and thereby prevents sex-specific lethality. Dosage compensation is achieved by a protein complex that associates with X in a sex-specific fashion to modulate gene expression. SDC-3, a protein that coordinately controls both sex determination and dosage compensation, activates dosage compensation by directing the dosage compensation protein complex to the hermaphrodite X chromosomes. We show that SDC-3 coordinates this assembly through its own sex-specific association with X. SDC-3 in turn requires other members of the dosage compensation gene hierarchy for its stability and its X localization. In addition, SDC-3 requires its own zinc finger motifs and an amino-terminal region for its X association. Our experiments suggest the possible involvement of zinc finger motifs in X chromosome recognition and the amino-terminal region in interactions with other dosage compensation proteins.

Chromatin loop structure of the human X chromosome: relevance to X inactivation and CpG clusters

1989 ◽  
Vol 9 (6) ◽  
pp. 2322-2331
Author(s):  
A H Beggs ◽  
B R Migeon
Keyword(s):  
Cpg Islands ◽  
Phosphoglycerate Kinase ◽  
Housekeeping Genes ◽  
Factor Ix ◽  
Clotting Factor ◽  
Order Structure ◽  
Chromatin Loop ◽  
X Chromosomes ◽  
Alpha Galactosidase ◽  
Glucose 6 Phosphate Dehydrogenase

Part of the higher-order structure of chromatin is achieved by constraining DNA in loops ranging in size from 30 to 100 kilobase pairs; these loops have been implicated in defining functional domains and replicons and possibly in facilitating transcription. Because the human active and inactive X chromosomes differ in transcriptional activity and replication, we looked for differences in their chromatin loop structures. Since the islands of CpG-rich DNA at the 5' ends of X-linked housekeeping genes are the regions where functional differences in DNA methylation and nuclease sensitivity are found, we looked for scaffold association of these sequences after extraction of histones with lithium diiodosalicylate. Specifically, we examined the 5' CpG islands within the hypoxanthine phosphoribosyltransferase, glucose 6-phosphate dehydrogenase, P3, GdX, phosphoglycerate kinase type 1, and alpha-galactosidase loci in human lymphoblasts obtained from individuals with 1 to 4 X chromosomes. Although we detected no scaffold-associated regions near these genes, we found several such regions at the ornithine transcarbamylase and blood clotting factor IX loci. Our results suggest that the CpG islands are excluded from the nuclear scaffold and that even though transcriptionally active, housekeeping genes are less likely than X-linked tissue-specific genes to be scaffold associated. In all cases, the pattern of scaffold association was the same for loci on active and inactive X chromosomes.

scholarly journals Paroxysmal Nocturnal Hemoglobinuria with Glucose-6-Phosphate Dehydrogenase Deficiency: A Case Report and Review of the Literature

2019 ◽  
Vol 12 (3) ◽  
pp. 838-844
Author(s):  
Mahmoud S. Eisa ◽  
Shehab F. Mohamed ◽  
Firyal Ibrahim ◽  
Khalid Shariff ◽  
Nagham Sadik ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
G6pd Deficiency ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Dehydrogenase Deficiency ◽  
Response To Treatment ◽  
X Chromosomes ◽  
Financial Status ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Real Challenge ◽  
And Oxidative Stress

In this study, we are describing a female patient with paroxysmal nocturnal hemoglobinuria (PNH) and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Both diseases are known to cause hemolytic anemia that mediates the hemolysis of RBCs through several mechanisms. In PNH the hemolysis is mediated through complement activation and oxidative stress. G6PD enzyme is crucial in preventing damage to cellular structures caused by oxygen-free radicles. In G6PD deficiency the hemolysis is mediated through the oxidative stress created by oxygen-free radicles. Since both diseases mediate hemolysis through the oxidative stress, we hypothesize that both conditions have facilitated an effect on each other and this will reflect on the response to treatment, and this response to treatment could vary based on whether the two mutations occurred in the same gene or in two different X chromosomes. Having diagnosed PNH, the management is very expensive and not all the patients can afford it, especially our patient who is a maid by occupation. So, the real challenge in our case is to monitor her in subsequent visits and to plan the treatment keeping in mind her financial status.

Use of a reversed-phase evaporation vesicle formulation for a homogeneous liposome immunoassay.

1986 ◽  
Vol 32 (9) ◽  
pp. 1687-1691 ◽  
Author(s):  
E Canova-Davis ◽  
C T Redemann ◽  
Y P Vollmer ◽  
V T Kung
Keyword(s):  
Enzyme Activity ◽  
Colorimetric Detection ◽  
Reversed Phase ◽  
Homogeneous Immunoassay ◽  
Bacterial Enzyme ◽  
Liposome Preparation ◽  
Enzyme Molecules ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Relevant Range ◽  
Serum Components

Abstract Complement-mediated release of enzyme molecules from reversed-phase evaporation vesicles serves as the basis of the sensitive homogeneous immunoassay reported here. We found it necessary to co-entrap the substrate glucose 6-phosphate with the bacterial enzyme glucose-6-phosphate dehydrogenase (EC 1.1.1.49) to protect enzyme activity during liposome preparation. Enzyme can be released specifically from these liposomes by incubation with antibody and complement. the enzyme is not merely available to substrate but is actually physically free of the liposomes. Inhibition of this complement-mediated lysis by theophylline is the basis for the homogeneous liposome immunoassay described. The assay results vary linearly with theophylline concentrations in plasma in the clinically relevant range, and serum components do not interfere. The reagents in the assay kit are stable for at least seven months when stored at 5 degrees C. No nontheophylline compounds reacted significantly with the antiserum used. The assay can be run in a kinetic format, with either ultraviolet or colorimetric detection.

scholarly journals G-6-PD Long Prairie: a new glucose-6-phosphate dehydrogenase mutant exhibiting normal sensitivity to inhibition by NADPH and accompanied by nonspherocytic hemolytic anemia

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 247-251 ◽  
Author(s):  
GJ Johnson ◽  
ME Kaplan ◽  
E Beutler
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Alternative Mechanism ◽  
Ph Optimum ◽  
Intracellular Enzyme ◽  
Chronic Hemolysis ◽  
Increased Sensitivity ◽  
Normal Sensitivity ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Heat Instability

Abstract The enzymatic properties of a new glucose-6-phosphate dehydrogenase (G- 6-PD) variant (G-6-PD Long Prairie) were studied in a white patient with chronic nonspherocytic hemolysis. The red cells were found to have 2.3%-7.7% normal enzymatic activity. The mutant enzyme exhibited marked heat instability, an increased pH optimum, a moderately decreased Km for G-6-P, and increased utilization of 2-deoxyglucose-6-phosphate and deamino NADP. The Km for NADP and Ki for NADPH were both normal. G-6-PD Long Prairie is an interesting new G-6-PD variant that demonstrates that chronic hemolysis can be associated with modestly decreased G-6-PD activity despite normal sensitivity to inhibition by NADPH. Although increased sensitivity to inhibition by NADPH has been postulated to decrease intracellular enzyme activity, resulting in enhanced susceptibility to hemolysis in certain G-6-PD variants with only moderately decreased enzymatic activity, an alternative mechanism of hemolysis, possibly enzyme thermolability, exists in G-6-PD Long Prairie.

scholarly journals Glucose-6-phosphate dehydrogenase deficiency in the Han Chinese population: molecular characterization and genotype–phenotype association throughout an activity distribution

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ying He ◽  
Yinhui Zhang ◽  
Xionghao Chen ◽  
Qiong Wang ◽  
Lifen Ling ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
G6pd Deficiency ◽  
National Level ◽  
Gene Mutations ◽  
Single Mutation ◽  
Missense Mutations ◽  
Severe Deficiency ◽  
Compound Mutation ◽  
Normal Males ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common hereditary disorder in China. The existing prevalence and molecular epidemiology of G6PD deficiency in China were geographically limited. In this study, the spectrum of G6PD gene mutations was well characterized in a large and diverse population all over the country; and the correlation of genotype and enzyme activity phenotype was explored for the first time. The results showed that the overall prevalence of G6PD deficiency in China was 2.10% at the national level. The top six common mutations were c.1388 G>A, c.1376 G>T, c.95 A>G, c.392 G>T, c.871 G>A and c.1024 C>T, accounting for more than 90% of G6PD deficient alleles. Compound mutation patterns were frequently observed in females with severe deficiency. The distribution of G6PD activities depended on the type of mutation patterns and genders. Hemizygote, homozygote, and compound heterozygote were predominantly associated with severe G6PD deficiency, whereas heterozygotes with single mutation mainly presented moderate enzyme deficiency. A significant gap between G6PD activities in hemizygous and normal males was observed, and yet, the overall distribution of that in females carrying missense mutations was a continuum from G6PD severely deficient to normal. This is the first report of discussing the association between G6PD genetic variants in the Chinese and enzyme activity phenotypes.

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