miR-11 regulates pupal size of Drosophila melanogaster via directly targeting Ras85D

MicroRNAs play diverse roles in various physiological processes during Drosophila development. In the present study, we reported that miR-11 regulates pupal size during Drosophila metamorphosis via targeting Ras85D with the following evidences: pupal size was increased in the miR-11 deletion mutant; restoration of miR-11 in the miR-11 deletion mutant rescued the increased pupal size phenotype observed in the miR-11 deletion mutant; ectopic expression of miR-11 in brain insulin-producing cells (IPCs) and whole body shows consistent alteration of pupal size; Dilps and Ras85D expressions were negatively regulated by miR-11 in vivo; miR-11 targets Ras85D through directly binding to Ras85D 3′-untranslated region in vitro; removal of one copy of Ras85D in the miR-11 deletion mutant rescued the increased pupal size phenotype observed in the miR-11 deletion mutant. Thus, our current work provides a novel mechanism of pupal size determination by microRNAs during Drosophila melanogaster metamorphosis.

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The 5′ Untranslated Region and Gag product of Idefix, a Long Terminal Repeat-Retrotransposon from Drosophila melanogaster, Act Together To Initiate a Switch between Translated and Untranslated States of the Genomic mRNA

Molecular and Cellular Biology ◽

10.1128/mcb.23.22.8246-8254.2003 ◽

2003 ◽

Vol 23 (22) ◽

pp. 8246-8254 ◽

Cited By ~ 14

Author(s):

Carine Meignin ◽

Jean-Luc Bailly ◽

Frédérick Arnaud ◽

Bernard Dastugue ◽

Chantal Vaury

Keyword(s):

Drosophila Melanogaster ◽

Long Terminal Repeat ◽

Untranslated Region ◽

Terminal Repeat ◽

Entry Site ◽

Independent Manner ◽

Gag Protein ◽

Genomic Arrangement

ABSTRACT Idefix is a long terminal repeat (LTR)-retrotransposon present in Drosophila melanogaster which shares similarities with vertebrates retroviruses both in its genomic arrangement and in the mechanism of transposition. Like in retroviruses, its two LTRs flank a long 5′ untranslated region (5′UTR) and three open reading frames referred to as the gag, pol, and env genes. Here we report that its 5′UTR, located upstream of the gag gene, can fold into highly structured domains that are known to be incompatible with efficient translation by ribosome scanning. Using dicistronic plasmids analyzed by both (i) in vitro transcription and translation in rabbit reticulocyte or wheat germ lysates and (ii) in vivo expression in transgenic flies, we show that the 5′UTR of Idefix exhibits an internal ribosome entry site (IRES) activity that is able to promote translation of a downstream cistron in a cap-independent manner. The functional state of this novel IRES depends on eukaryotic factors that are independent of their host origin. However, in vivo, its function can be down-regulated by trans-acting factors specific to tissues or developmental stages of its host. We identify one of these trans-acting factors as the Gag protein encoded by Idefix itself. Our data support a model in which nascent Gag is able to block translation initiated from the viral mRNA and thus its own translation. These data highlight the fact that LTR-retrotransposons may autoregulate their replication cycle through their Gag production.

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Arginine-Rich Regions Mediate the RNA Binding and Regulatory Activities of the Protein Encoded by the Drosophila melanogaster suppressor of sable Gene

Molecular and Cellular Biology ◽

10.1128/mcb.20.21.8198-8208.2000 ◽

2000 ◽

Vol 20 (21) ◽

pp. 8198-8208 ◽

Cited By ~ 7

Author(s):

Michael A. Turnage ◽

Paul Brewer-Jensen ◽

Wen-Li Bai ◽

Lillie L. Searles

Keyword(s):

Drosophila Melanogaster ◽

Rna Binding ◽

Consensus Sequence ◽

Polytene Chromosomes ◽

Ectopic Expression ◽

Binding Activity ◽

Suppressor Of Sable ◽

Rna Accumulation

ABSTRACT The Drosophila melanogaster suppressor of sable gene,su(s), encodes a novel, 150-kDa nuclear RNA binding protein, SU(S), that negatively regulates RNA accumulation from mutant alleles of other genes that have transposon insertions in the 5′ transcribed region. In this study, we delineated the RNA binding domain of SU(S) and evaluated its relevance to SU(S) function in vivo. As a result, we have defined two arginine-rich motifs (ARM1 and ARM2) that mediate the RNA binding activity of SU(S). ARM1 is required for in vitro high-affinity binding of SU(S) to small RNAs that were previously isolated by SELEX (binding site selection assay) and that contain a common consensus sequence. ARM1 is also required for the association of SU(S) with larval polytene chromosomes in vivo. ARM2 promotes binding of SU(S) to SELEX RNAs that lack the consensus sequence and apparently is neither necessary nor sufficient for the stable polytene chromosome association of SU(S). Use of the GAL4/UAS system to drive ectopic expression of su(s) cDNA transgenes revealed two previously unknown properties of SU(S). First, overexpression of SU(S) is lethal. Second, SU(S) negatively regulates expression of su(s)intronless cDNA transgenes, and the ARMs are required for this effect. Considering these and previous results, we propose that SU(S) binds to the 5′ region of nascent transcripts and inhibits RNA production in a manner that can be overcome by splicing complex assembly.

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The Tetracycline-Controlled Transactivator (Tet-On/Off) System in Beta Cells Reduces Insulin Expression and Secretion in Mice

10.2337/figshare.16713151 ◽

2021 ◽

Author(s):

Nathalie Jouvet ◽

Khalil Bouyakdan ◽

Scott A. Campbell ◽

Cindy Baldwin ◽

Shannon E. Townsend ◽

...

Keyword(s):

Insulin Secretion ◽

Beta Cell ◽

Beta Cells ◽

Cell Biology ◽

Genetic Manipulation ◽

Ectopic Expression ◽

Whole Body ◽

Specific Gene

Controllable genetic manipulation is an indispensable tool in research, greatly advancing our understanding of cell biology and physiology. However in beta cells, transgene silencing, low inducibility, ectopic expression and off-targets effects are persistent challenges. In this study, we investigated whether an inducible, Tet-Off system with beta-cell specific MIP-itTA driven expression of TetO-CreJaw/J could circumvent previous issues of specificity and efficacy. Following assessment of tissue-specific gene recombination; beta cell architecture; in vitro and in vivo glucose-stimulated insulin secretion; and whole-body glucose homeostasis, we discovered that expression of any tetracycline-controlled transactivator (e.g. itTA, rtTA or tTA) in beta cells significantly reduced Insulin gene expression and decreased insulin content. This translated into lower pancreatic insulin levels and reduced insulin secretion in mice carrying any tTA transgene, independent of Cre recombinase expression or doxycycline exposure. Our study echoes ongoing challenges faced by fundamental researchers working with beta cells and highlights the need for consistent and comprehensive controls when using the Tet-On or Tet-Off systems for genome editing.

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The Tetracycline-Controlled Transactivator (Tet-On/Off) System in Beta Cells Reduces Insulin Expression and Secretion in Mice

10.2337/figshare.16713151.v1 ◽

2021 ◽

Author(s):

Nathalie Jouvet ◽

Khalil Bouyakdan ◽

Scott A. Campbell ◽

Cindy Baldwin ◽

Shannon E. Townsend ◽

...

Keyword(s):

Insulin Secretion ◽

Beta Cell ◽

Beta Cells ◽

Cell Biology ◽

Genetic Manipulation ◽

Ectopic Expression ◽

Whole Body ◽

Specific Gene

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Differentiation of mesenchymal stem cells from humans and animals into insulin-producing cells: An overview in vitro induction forms

Current Stem Cell Research & Therapy ◽

10.2174/1574888x16666201229124429 ◽

2020 ◽

Vol 16 ◽

Author(s):

Bruna O. S. Câmara ◽

Bruno M. Bertassoli ◽

Natália M. Ocarino ◽

Rogéria Serakides

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Culture Medium ◽

Adipogenic Differentiation ◽

Medium Composition ◽

Cell Therapies ◽

Insulin Producing Cells ◽

Msc Differentiation

The use of stem cells in cell therapies has shown promising results in the treatment of several diseases, including diabetes mellitus, in both humans and animals. Mesenchymal stem cells (MSCs) can be isolated from various locations, including bone marrow, adipose tissues, synovia, muscles, dental pulp, umbilical cords, and the placenta. In vitro, by manipulating the composition of the culture medium or transfection, MSCs can differentiate into several cell lineages, including insulin-producing cells (IPCs). Unlike osteogenic, chondrogenic, and adipogenic differentiation, for which the culture medium and time are similar between studies, studies involving the induction of MSC differentiation in IPCs differ greatly. This divergence is usually evident in relation to the differentiation technique used, the composition of the culture medium, the cultivation time, which can vary from a few hours to several months, and the number of steps to complete differentiation. However, although there is no “gold standard” differentiation medium composition, most prominent studies mention the use of nicotinamide, exedin-4, ß-mercaptoethanol, fibroblast growth factor b (FGFb), and glucose in the culture medium to promote the differentiation of MSCs into IPCs. Therefore, the purpose of this review is to investigate the stages of MSC differentiation into IPCs both in vivo and in vitro, as well as address differentiation techniques and molecular actions and mechanisms by which some substances, such as nicotinamide, exedin-4, ßmercaptoethanol, FGFb, and glucose, participate in the differentiation process.

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Use of Toxicokinetics in Risk Assessment Based on In Vitro Data

Alternatives to Laboratory Animals ◽

10.1177/026119299302100209 ◽

1993 ◽

Vol 21 (2) ◽

pp. 173-180

Author(s):

Gunnar Johanson

Keyword(s):

Risk Assessment ◽

Whole Body ◽

External Exposure ◽

Target Dose ◽

Toxic Response ◽

Route Of Exposure ◽

Vitro Data ◽

In Vitro Data

This presentation addresses some aspects of the methodology, advantages and problems associated with toxicokinetic modelling based on in vitro data. By using toxicokinetic models, particularly physiologically-based ones, it is possible, in principle, to describe whole body toxicokinetics, target doses and toxic effects from in vitro data. Modelling can be divided into three major steps: 1) to relate external exposure (applied dose) of xenobiotic to target dose; 2) to establish the relationship between target dose and effect (in vitro data, e.g. metabolism in microsomes, partitioning in tissue homogenates, and toxicity in cell cultures, are useful in both steps); and 3) to relate external exposure to toxic effect by combining the first two steps. Extrapolations from in vitro to in vivo, between animal and man, and between high and low doses, can easily be carried out by toxicokinetic simulations. In addition, several factors that may affect the toxic response by changing the target dose, such as route of exposure and physical activity, can be studied. New insights concerning the processes involved in toxicity often emerge during the design, refinement and validation of the model. The modelling approach is illustrated by two examples: 1) the carcinogenicity of 1,3-butadiene; and 2) the haematotoxicity of 2-butoxyethanol. Toxicokinetic modelling is an important tool in toxicological risk assessment based on in vitro data. Many factors, some of which can, and should be, studied in vitro, are involved in the expression of toxicity. Successful modelling depends on the identification and quantification of these factors.

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Adipocyte PHLPP2 inhibition prevents obesity-induced fatty liver

Nature Communications ◽

10.1038/s41467-021-22106-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

KyeongJin Kim ◽

Jin Ku Kang ◽

Young Hoon Jung ◽

Sang Bae Lee ◽

Raffaela Rametta ◽

...

Keyword(s):

Fatty Liver ◽

Whole Body ◽

Acid Oxidation ◽

Chow Diet ◽

Peroxisome Proliferator ◽

Obese Mice ◽

Ph Domain ◽

Peroxisome Proliferator Activated Receptor

AbstractIncreased adiposity confers risk for systemic insulin resistance and type 2 diabetes (T2D), but mechanisms underlying this pathogenic inter-organ crosstalk are incompletely understood. We find PHLPP2 (PH domain and leucine rich repeat protein phosphatase 2), recently identified as the Akt Ser473 phosphatase, to be increased in adipocytes from obese mice. To identify the functional consequence of increased adipocyte PHLPP2 in obese mice, we generated adipocyte-specific PHLPP2 knockout (A-PHLPP2) mice. A-PHLPP2 mice show normal adiposity and glucose metabolism when fed a normal chow diet, but reduced adiposity and improved whole-body glucose tolerance as compared to Cre- controls with high-fat diet (HFD) feeding. Notably, HFD-fed A-PHLPP2 mice show increased HSL phosphorylation, leading to increased lipolysis in vitro and in vivo. Mobilized adipocyte fatty acids are oxidized, leading to increased peroxisome proliferator-activated receptor alpha (PPARα)-dependent adiponectin secretion, which in turn increases hepatic fatty acid oxidation to ameliorate obesity-induced fatty liver. Consistently, adipose PHLPP2 expression is negatively correlated with serum adiponectin levels in obese humans. Overall, these data implicate an adipocyte PHLPP2-HSL-PPARα signaling axis to regulate systemic glucose and lipid homeostasis, and suggest that excess adipocyte PHLPP2 explains decreased adiponectin secretion and downstream metabolic consequence in obesity.

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Synthesis, Quantification, and Characterization of Fatty Acid Amides from In Vitro and In Vivo Sources

Molecules ◽

10.3390/molecules26092543 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2543

Author(s):

Ruidong Ni ◽

Suzeeta Bhandari ◽

Perry R. Mitchell ◽

Gabriela Suarez ◽

Neel B. Patel ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Fatty Acid ◽

Apis Mellifera ◽

Chemical Synthesis ◽

Acid Amide ◽

Fatty Acid Amides ◽

Fatty Acid Amide

Fatty acid amides are a diverse family of underappreciated, biologically occurring lipids. Herein, the methods for the chemical synthesis and subsequent characterization of specific members of the fatty acid amide family are described. The synthetically prepared fatty acid amides and those obtained commercially are used as standards for the characterization and quantification of the fatty acid amides produced by biological systems, a fatty acid amidome. The fatty acid amidomes from mouse N18TG2 cells, sheep choroid plexus cells, Drosophila melanogaster, Bombyx mori, Apis mellifera, and Tribolium castaneum are presented.

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In Vivo and In Vitro Assays Evaluating the Biological Activity of Taurine, Glucose and Energetic Beverages

Molecules ◽

10.3390/molecules26082198 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2198

Author(s):

Marcos Mateo-Fernández ◽

Fernando Valenzuela-Gómez ◽

Rafael Font ◽

Mercedes Del Río-Celestino ◽

Tania Merinas-Amo ◽

...

Keyword(s):

Dna Damage ◽

Drosophila Melanogaster ◽

Biological Activity ◽

Biological Effects ◽

Methylation Status ◽

Repetitive Sequences ◽

Energy Drinks ◽

Red Bull

Taurine is one of the main ingredients used in energy drinks which are highly consumed in adolescents for their sugary taste and stimulating effect. With energy drinks becoming a worldwide phenomenon, the biological effects of these beverages must be evaluated in order to fully comprehend the potential impact of these products on the health due to the fact nutrition is closely related to science since the population consumes food to prevent certain diseases. Therefore, the aim of this study was to evaluate the biological effects of taurine, glucose, classic Red Bull® and sugar-free Red Bull® in order to check the food safety and the nutraceutical potential of these compounds, characterising different endpoints: (i) Toxicology, antitoxicology, genotoxicology and life expectancy assays were performed in the Drosophila melanogaster model organism; (ii) The in vitro chemopreventive activity of testing compounds was determined by assessing their cytotoxicity, the proapoptotic DNA-damage capability to induce internucleosomal fragmentation, the strand breaks activity and the modulator role on the methylation status of genomic repetitive sequences of HL-60 promyelocytic cells. Whereas none tested compounds showed toxic or genotoxic effect, all tested compounds exerted antitoxic and antigenotoxic activity in Drosophila. Glucose, classic Red Bull® and sugar-free Red Bull® were cytotoxic in HL-60 cell line. Classic Red Bull® induced DNA internucleosomal fragmentation although none of them exhibited DNA damage on human leukaemia cells. In conclusion, the tested compounds are safe on Drosophila melanogaster and classic Red Bull® could overall possess nutraceutical potential in the in vivo and in vitro model used in this study. Besides, taurine could holistically be one of the bioactive compounds responsible for the biological activity of classic Red Bull®.

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Influence of Dopamine on Fluorescent Advanced Glycation End Products Formation Using Drosophila melanogaster

Biomolecules ◽

10.3390/biom11030453 ◽

2021 ◽

Vol 11 (3) ◽

pp. 453

Author(s):

Ana Filošević Vujnović ◽

Katarina Jović ◽

Emanuel Pištan ◽

Rozi Andretić Waldowski

Keyword(s):

Drosophila Melanogaster ◽

Advanced Glycation End Products ◽

Model Organism ◽

Covalent Modification ◽

Advanced Glycation ◽

Biomarkers Of Aging ◽

Glycation End Products ◽

End Products

Non-enzymatic glycation and covalent modification of proteins leads to Advanced Glycation End products (AGEs). AGEs are biomarkers of aging and neurodegenerative disease, and can be induced by impaired neuronal signaling. The objective of this study was to investigate if manipulation of dopamine (DA) in vitro using the model protein, bovine serum albumin (BSA), and in vivo using the model organism Drosophila melanogaster, influences fluorescent AGEs (fAGEs) formation as an indicator of dopamine-induced oxidation events. DA inhibited fAGEs-BSA synthesis in vitro, suggesting an anti-oxidative effect, which was not observed when flies were fed DA. Feeding flies cocaine and methamphetamine led to increased fAGEs formation. Mutants lacking the dopaminergic transporter or the D1-type showed further elevation of fAGEs accumulation, indicating that the long-term perturbation in DA function leads to higher production of fAGEs. To confirm that DA has oxidative properties in vivo, we fed flies antioxidant quercetin (QUE) together with methamphetamine. QUE significantly decreased methamphetamine-induced fAGEs formation suggesting that the perturbation of DA function in vivo leads to increased oxidation. These findings present arguments for the use of fAGEs as a biomarker of DA-associated neurodegenerative changes and for assessment of antioxidant interventions such as QUE treatment.

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