scholarly journals A Family Knockout of All Four Drosophila Metallothioneins Reveals a Central Role in Copper Homeostasis and Detoxification

2006 ◽  
Vol 26 (6) ◽  
pp. 2286-2296 ◽  
Author(s):  
Dieter Egli ◽  
Hasmik Yepiskoposyan ◽  
Anand Selvaraj ◽  
Kuppusamy Balamurugan ◽  
Rama Rajaram ◽  
...  
Keyword(s):  
Gene Family ◽  
Tissue Specificity ◽  
Biochemical Characterization ◽  
Adult Males ◽  
Metallothionein Gene ◽  
Copper Cells ◽  
Complex Forms ◽  
Main Regulator ◽  
Distribution In The Organism

ABSTRACT Metallothioneins are ubiquitous, small, cysteine-rich proteins with the ability to bind heavy metals. In spite of their biochemical characterization, their in vivo function remains elusive. Here, we report the generation of a metallothionein gene family knockout in Drosophila melanogaster by targeted disruption of all four genes (MtnA to -D). These flies are viable if raised in standard laboratory food. During development, however, they are highly sensitive to copper, cadmium, and (to a lesser extent) zinc load. Metallothionein expression is particularly important for male viability; while copper load during development affects males and females equally, adult males lacking metallothioneins display a severely reduced life span, possibly due to copper-mediated oxidative stress. Using various reporter gene constructs, we find that different metallothioneins are expressed with virtually the same tissue specificity in larvae, notably in the intestinal tract at sites of metal accumulation, including the midgut's “copper cells.” The same expression pattern is observed with a synthetic minipromoter consisting only of four tandem metal response elements. From these and other experiments, we conclude that tissue specificity of metallothionein expression is a consequence, rather than a cause, of metal distribution in the organism. The bright orange luminescence of copper accumulated in copper cells of the midgut is severely reduced in the metallothionein gene family knockout, as well as in mutants of metal-responsive transcription factor 1 (MTF-1), the main regulator of metallothionein expression. This indicates that an in vivo metallothionein-copper complex forms the basis of this luminescence. Strikingly, metallothionein mutants show an increased, MTF-1-dependent induction of metallothionein promoters in response to copper, cadmium, silver, zinc, and mercury. We conclude that free metal, but not metallothionein-bound metal, triggers the activation of MTF-1 and that metallothioneins regulate their own expression by a negative feedback loop.

scholarly journals Expression of a yeast metallothionein gene family is activated by a single metalloregulatory transcription factor.

1992 ◽  
Vol 12 (9) ◽  
pp. 3766-3775 ◽  
Author(s):  
P Zhou ◽  
M S Szczypka ◽  
T Sosinowski ◽  
D J Thiele
Keyword(s):  
Gene Family ◽  
Protein Complexes ◽  
Copper Resistance ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pathogenic Yeast ◽  
Selection Scheme ◽  
Metallothionein Gene ◽  
Metal Levels ◽  
Opportunistic Pathogenic

The opportunistic pathogenic yeast Candida glabrata elicits at least two major responses in the presence of high environmental metal levels: transcriptional induction of the metallothionein gene family by copper and the appearance of small (gamma-Glu-Cys)nGly peptides in the presence of cadmium. On the basis of a trans-activation selection scheme in the baker's yeast Saccharomyces cerevisiae, we previously isolated a C. glabrata gene which encodes a copper-activated DNA-binding protein designated AMT1. AMT1 forms multiple specific DNA-protein complexes with both C. glabrata MT-I and MT-IIa promoter DNA fragments. In this report, we localize and define the AMT1-binding sites in the MT-I and MT-IIa promoters and characterize the mode of AMT1 binding. Furthermore, we demonstrate that the AMT1 protein trans activates both the MT-I and MT-IIa genes in vivo in response to copper and that this activation is essential for high-level copper resistance in C. glabrata. Although AMT1-mediated trans activation of the C. glabrata metallothionein genes is essential for copper resistance, AMT1 is completely dispensable for cadmium tolerance. The distinct function that metallothionein genes have in copper but not cadmium detoxification in C. glabrata is in contrast to the role that metallothionein genes play in tolerance to multiple metals in higher organisms.

Expression of a yeast metallothionein gene family is activated by a single metalloregulatory transcription factor

1992 ◽  
Vol 12 (9) ◽  
pp. 3766-3775
Author(s):  
P Zhou ◽  
M S Szczypka ◽  
T Sosinowski ◽  
D J Thiele
Keyword(s):  
Gene Family ◽  
Protein Complexes ◽  
Copper Resistance ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pathogenic Yeast ◽  
Selection Scheme ◽  
Metallothionein Gene ◽  
Metal Levels ◽  
Opportunistic Pathogenic

The opportunistic pathogenic yeast Candida glabrata elicits at least two major responses in the presence of high environmental metal levels: transcriptional induction of the metallothionein gene family by copper and the appearance of small (gamma-Glu-Cys)nGly peptides in the presence of cadmium. On the basis of a trans-activation selection scheme in the baker's yeast Saccharomyces cerevisiae, we previously isolated a C. glabrata gene which encodes a copper-activated DNA-binding protein designated AMT1. AMT1 forms multiple specific DNA-protein complexes with both C. glabrata MT-I and MT-IIa promoter DNA fragments. In this report, we localize and define the AMT1-binding sites in the MT-I and MT-IIa promoters and characterize the mode of AMT1 binding. Furthermore, we demonstrate that the AMT1 protein trans activates both the MT-I and MT-IIa genes in vivo in response to copper and that this activation is essential for high-level copper resistance in C. glabrata. Although AMT1-mediated trans activation of the C. glabrata metallothionein genes is essential for copper resistance, AMT1 is completely dispensable for cadmium tolerance. The distinct function that metallothionein genes have in copper but not cadmium detoxification in C. glabrata is in contrast to the role that metallothionein genes play in tolerance to multiple metals in higher organisms.

The Hierarchic Order of Intermediate Filament Structure and Assembly

1985 ◽  
Vol 43 ◽  
pp. 722-725
Author(s):  
U. Aebi ◽  
E.C. Glavaris ◽  
R. Eichner
Keyword(s):  
Tissue Specificity ◽  
Structural Model ◽  
Eukaryotic Cells ◽  
Cdna Sequencing ◽  
Filament Structure ◽  
Keratin Filaments ◽  
Isoelectric Points ◽  
Immunological Crossreactivity

Five different classes of intermediate-sized filaments (IFs) have been identified in differentiated eukaryotic cells: vimentin in mesenchymal cells, desmin in muscle cells, neurofilaments in nerve cells, glial filaments in glial cells and keratin filaments in epithelial cells. Despite their tissue specificity, all IFs share several common attributes, including immunological crossreactivity, similar morphology (e.g. about 10 nm diameter - hence ‘10-nm filaments’) and the ability to reassemble in vitro from denatured subunits into filaments virtually indistinguishable from those observed in vivo. Further more, despite their proteinchemical heterogeneity (their MWs range from 40 kDa to 200 kDa and their isoelectric points from about 5 to 8), protein and cDNA sequencing of several IF polypeptides (for refs, see 1,2) have provided the framework for a common structural model of all IF subunits.

The in vivo distribution and dynamics of DNA topoisomerase II in Drosophila embryonic nuclei and chromosomes

1993 ◽  
Vol 51 ◽  
pp. 74-75
Author(s):  
Jason R. Swedlow ◽  
Neil Osheroff ◽  
Tim Karr ◽  
John W. Sedat ◽  
David A. Agard
Keyword(s):  
Topoisomerase Ii ◽  
Biochemical Characterization ◽  
Developmental Cycle ◽  
Dna Topoisomerase Ii ◽  
Chromosomal Distribution ◽  
Dna Topoisomerase ◽  
Ideal System ◽  
Dnase Treatment

DNA topoisomerase II is an ATP-dependent double-stranded DNA strand-passing enzyme that is necessary for full condensation of chromosomes and for complete segregation of sister chromatids at mitosis in vivo and in vitro. Biochemical characterization of chromosomes or nuclei after extraction with high-salt or detergents and DNAse treatment showed that topoisomerase II was a major component of this remnant, termed the chromosome scaffold. The scaffold has been hypothesized to be the structural backbone of the chromosome, so the localization of topoisomerase II to die scaffold suggested that the enzyme might play a structural role in the chromosome. However, topoisomerase II has not been studied in nuclei or chromosomes in vivo. We have monitored the chromosomal distribution of topoisomerase II in vivo during mitosis in the Drosophila embryo. This embryo forms a multi-nucleated syncytial blastoderm early in its developmental cycle. During this time, the embryonic nuclei synchronously progress through 13 mitotic cycles, so this is an ideal system to follow nuclear and chromosomal dynamics.

Iron-induced expression of BMP6 in intestinal cells is the main regulator of hepatic hepcidin expression in vivo

2010 ◽  
Vol 48 (01) ◽  
Author(s):  
S Arndt ◽  
U Mägdefrau ◽  
C Dorn ◽  
K Schardt ◽  
AK Bosserhoff ◽  
...  
Keyword(s):  
Intestinal Cells ◽  
Induced Expression ◽  
Hepcidin Expression ◽  
Main Regulator

scholarly journals Periplaneta americana Oligosaccharides Exert Anti-Inflammatory Activity through Immunoregulation and Modulation of Gut Microbiota in Acute Colitis Mice Model

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1718
Author(s):  
Kaimin Lu ◽  
Jing Zhou ◽  
Jie Deng ◽  
Yangjun Li ◽  
Chuanfang Wu ◽  
...  
Keyword(s):  
Side Effects ◽  
Pathogenic Bacteria ◽  
Periplaneta Americana ◽  
Biochemical Characterization ◽  
Antioxidant Activities ◽  
Inflammatory Activity ◽  
Mice Model ◽  
Acute Colitis ◽  
Anti Inflammatory

The incidence and prevalence of inflammatory bowel disorders (IBD) are increasing around the world due to bacterial infection, abnormal immune response, etc. The conventional medicines for IBD treatment possess serious side effects. Periplaneta americana (P. americana), a traditional Chinese medicine, has been used to treat arthritis, fever, aches, inflammation, and other diseases. This study aimed to evaluate the anti-inflammatory effects of oligosaccharides from P. Americana (OPA) and its possible mechanisms in vivo. OPA were purified and biochemical characterization was analyzed by HPGPC, HPLC, FT-IR, and GC–MS. Acute colitis mice model was established, the acute toxicity and anti-inflammatory activity were tested in vivo. The results showed OPA with molecular mass of 1.0 kDa were composed of 83% glucose, 6% galactose, 11% xylose, and the backbone was (1→4)-Glcp. OPA had potent antioxidant activities in vitro and significantly alleviated the clinical symptoms of colitis, relieved colon damage without toxic side effects in vivo. OPA exhibited anti-inflammatory activity by regulating Th1/Th2, reducing oxidative stress, preserving intestinal barrier integrity, and inhibiting TLR4/MAPK/NF-κB pathway. Moreover, OPA protected gut by increasing microbial diversity and beneficial bacteria, and reducing pathogenic bacteria in feces. OPA might be the candidate of complementary and alternative medicines of IBD with low-cost and high safety.

scholarly journals Differential effects of chronic immunosuppression on behavioral, epigenetic, and Alzheimer’s disease-associated markers in 3xTg-AD mice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Minesh Kapadia ◽  
M. Firoz Mian ◽  
Donglai Ma ◽  
Craig P. Hutton ◽  
Amber Azam ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Emotional Reactivity ◽  
Histone Variant ◽  
In Vivo Model ◽  
Adult Males ◽  
Bdnf Expression ◽  
Systemic Autoimmunity ◽  
Circulating Autoantibodies

Abstract Background Circulating autoantibodies and sex-dependent discrepancy in prevalence are unexplained phenomena of Alzheimer’s disease (AD). Using the 3xTg-AD mouse model, we reported that adult males show early manifestations of systemic autoimmunity, increased emotional reactivity, enhanced expression of the histone variant macroH2A1 in the cerebral cortex, and loss of plaque/tangle pathology. Conversely, adult females display less severe autoimmunity and retain their AD-like phenotype. This study examines the link between immunity and other traits of the current 3xTg-AD model. Methods Young 3xTg-AD and wild-type mice drank a sucrose-laced 0.4 mg/ml solution of the immunosuppressant cyclophosphamide on weekends for 5 months. After behavioral phenotyping at 2 and 6 months of age, we assessed organ mass, serologic markers of autoimmunity, molecular markers of early AD pathology, and expression of genes associated with neurodegeneration. Results Chronic immunosuppression prevented hematocrit drop and reduced soluble Aβ in 3xTg-AD males while normalizing the expression of histone variant macroH2A1 in 3xTg-AD females. This treatment also reduced hepatosplenomegaly, lowered autoantibody levels, and increased the effector T cell population while decreasing the proportion of regulatory T cells in both sexes. Exposure to cyclophosphamide, however, neither prevented reduced brain mass and BDNF expression nor normalized increased tau and anxiety-related behaviors. Conclusion The results suggest that systemic autoimmunity increases soluble Aβ production and affects transcriptional regulation of macroH2A1 in a sex-related manner. Despite the complexity of multisystem interactions, 3xTg-AD mice can be a useful in vivo model for exploring the regulatory role of autoimmunity in the etiology of AD-like neurodegenerative disorders.

scholarly journals Cloning of mouse ptx3, a new member of the pentraxin gene family expressed at extrahepatic sites

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 1862-1872 ◽  
Author(s):  
M Introna ◽  
VV Alles ◽  
M Castellano ◽  
G Picardi ◽  
L De Gioia ◽  
...  
Keyword(s):  
Gene Family ◽  
Tertiary Structure ◽  
Helical Structure ◽  
Distinct Pattern ◽  
Mononuclear Phagocytes ◽  
Acute Phase Reactants ◽  
Inflammatory Reactions ◽  
Reactive Protein

Abstract Pentraxins, which include C reactive protein (CRP) and serum amyloid P component (SAP), are prototypic acute phase reactants that serve as indicators of inflammatory reactions. Here we report genomic and cDNA cloning of mouse ptx3 (mptx3), a member of the pentraxin gene family and characterize its extrahepatic expression in vitro and in vivo. mptx3 is organized into three exons on chromosome 3: the first (43 aa) and second exon (175 aa) code for the signal peptide and for a protein portion with no high similarity to known sequences the third (203 aa) for a domain related to classical pentraxins, which contains the “pentraxin family signature.” Analysis of the N terminal portion predicts a predominantly alpha helical structure, while the pentraxin domain of ptx3 is accommodated comfortably in the tertiary structure fold of SAP. Normal and transformed fibroblasts, undifferentiated and differentiated myoblasts, normal endothelial cells, and mononuclear phagocytes express mptx3 mRNA and release the protein in vitro on exposure to interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF)alpha. mptx3 was induced by bacterial lipopolysaccharide in vivo in a variety of organs and, most strongly, in the vascular endothelium of skeletal muscle and heart. Thus, mptx3 shows a distinct pattern of in vivo expression indicative of a significant role in cardiovascular and inflammatory pathology.

Sustained in vivo blockade of α1-adrenergic receptors prevented some of stress-triggered effects on steroidogenic machinery in Leydig cells

2013 ◽  
Vol 305 (2) ◽  
pp. E194-E204 ◽  
Author(s):  
Natasa J. Stojkov ◽  
Marija M. Janjic ◽  
Aleksandar Z. Baburski ◽  
Aleksandar I. Mihajlovic ◽  
Dragana M. Drljaca ◽  
...  
Keyword(s):  
Adrenergic Receptors ◽  
Leydig Cells ◽  
High Affinity ◽  
Testosterone Production ◽  
Transcription Profiles ◽  
Steroidogenic Cells ◽  
Main Regulator ◽  
Stimulatory Factor

This study was designed to systematically analyze and evaluate the effects of in vivo blockade of α1-adrenergic receptors (α1-ADRs) on the stress-induced disturbance of steroidogenic machinery in Leydig cells. Parameters followed 1) steroidogenic enzymes/proteins, transcription factors, and cAMP/testosterone production; 2) the main hallmarks of stress (epinephrine, glucocorticoids); and 3) transcription profiles of ADRs and oxidases with high affinity to inactivate glucocorticoids. Results showed that sustained blockade of α1-ADRs prevented stress-induced 1) decrease of the transcripts/proteins for main steroidogenic CYPs (CYP11A1, CYP17A1); 2) decrease of Scarb1 and Hsd3b1 transcripts; 3) decrease of transcript for Nur77, one of the main activator of the steroidogenic expression; and 4) increase of Dax1 and Arr19, the main steroidogenic repressors in Leydig cells. In the same cells, the expression of steroidogenic stimulatory factor Creb1, StAR, and androgen receptor increased. In this signaling scenario, stress-induced stimulation of Adra1a/Adra1b/Adrbk1 and Hsd11b2 (the unidirectional oxidase with high affinity to inactivate glucocorticoids) was not changed. Blockade additionally stimulated stress-increased transcription of the most abundantly expressed ADRs Adra1d/Adrb1/Adrb2 in Leydig cells. In the same cells, stress-decreased testosterone production, the main marker of Leydig cells functionality, was completely prevented, while reduction of cAMP, the main regulator of androgenesis, was partially prevented. Accordingly, the presented data provide a new molecular/transcriptional base for “fight/adaptation” of steroidogenic cells and new molecular insights into the role of α1-ADRs in stress-impaired Leydig cell steroidogenesis. The results are important in term of wide use of α1-ADR selective antagonists, alone/in combination, to treat high blood pressure, nightmares associated with posttraumatic stress disorder, and disrupted sexual health.

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