scholarly journals Characterizing a distal muscle enhancer in the mouse Igf2 locus

2016 ◽  
Vol 48 (2) ◽  
pp. 167-172 ◽  
Author(s):  
Damir Alzhanov ◽  
Peter Rotwein
Keyword(s):  
Skeletal Muscle ◽  
Transcriptional Control ◽  
Fluorescent Protein ◽  
Artificial Chromosome ◽  
Control Element ◽  
Specific Gene ◽  
Reporter System ◽  
Chromosomal Locus ◽  
Igf2 Gene

Insulin-like growth factor-2 (IGF2) is highly expressed in skeletal muscle and was identified as a quantitative trait locus for muscle mass. Yet little is known about mechanisms of its regulation in muscle. Recently, a DNA segment found ∼100 kb from the Igf2 gene was identified as a possible muscle transcriptional control element. Here we have developed an in vivo reporter system to assess this putative enhancer by substituting nuclear (n) EGFP for Igf2 coding exons in a bacterial artificial chromosome containing the mouse Igf2 - H19 chromosomal locus. After stable transfection into a mesenchymal stem cell line, individual clones were converted to myoblasts and underwent progressive muscle-specific gene expression and myotube formation in differentiation medium. Transgenic mRNA and nuclear-targeted enhanced green fluorescent protein were produced coincident with endogenous Igf2 mRNA, but only in lines containing an intact distal conserved DNA element. Our results show that a 294 bp DNA fragment containing two E-boxes is a necessary and sufficient long-range enhancer for induction of Igf2 gene transcription during skeletal muscle differentiation and provides a robust experimental platform for its further functional dissection.

scholarly journals In vivo analysis of mouse gastrin gene regulation in enhanced GFP-BAC transgenic mice

2011 ◽  
Vol 300 (2) ◽  
pp. G334-G344 ◽  
Author(s):  
Shigeo Takaishi ◽  
Wataru Shibata ◽  
Hiroyuki Tomita ◽  
Guangchun Jin ◽  
Xiangdong Yang ◽  
...  
Keyword(s):  
Transcriptional Control ◽  
Fluorescent Protein ◽  
Artificial Chromosome ◽  
Transitional Zone ◽  
Anterior Lobe ◽  
Gastric Antrum ◽  
Neuroendocrine Cells ◽  
Adult Mice ◽  
Green Fluorescent

Gastrin is secreted from a subset of neuroendocrine cells residing in the gastric antrum known as G cells, but low levels are also expressed in fetal pancreas and intestine and in many solid malignancies. Although past studies have suggested that antral gastrin is transcriptionally regulated by inflammation, gastric pH, somatostatin, and neoplastic transformation, the transcriptional regulation of gastrin has not previously been demonstrated in vivo. Here, we describe the creation of an enhanced green fluorescent protein reporter (mGAS-EGFP) mouse using a bacterial artificial chromosome that contains the entire mouse gastrin gene. Three founder lines expressed GFP signals in the gastric antrum and the transitional zone to the corpus. In addition, GFP(+) cells could be detected in the fetal pancreatic islets and small intestinal villi, but not in these organs of the adult mice. The administration of acid-suppressive reagents such as proton pump inhibitor omeprazole and gastrin/CCK-2 receptor antagonist YF476 significantly increased GFP signal intensity and GFP(+) cell numbers in the antrum, whereas these parameters were decreased by overnight fasting, octreotide (long-lasting somatostatin ortholog) infusion, and Helicobacter felis infection. GFP(+) cells were also detected in the anterior lobe of the pituitary gland and importantly in the colonic tumor cells induced by administration with azoxymethane and dextran sulfate sodium salt. This transgenic mouse provides a useful tool to study the regulation of mouse gastrin gene in vivo, thus contributing to our understanding of the mechanisms involved in transcriptional control of the gastrin gene.

scholarly journals Red Light/Green Light, a Dual Fluorescent Protein Reporter System To Study Enhancer-Promoter Specificity in Drosophila

2020 ◽  
Vol 10 (3) ◽  
pp. 985-997
Author(s):  
Eric M. Camino ◽  
Micheal L. Weinstein ◽  
Mary P. List ◽  
Jordan E. Vellky ◽  
Mark Rebeiz ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Red Light ◽  
Control Element ◽  
Gene Promoters ◽  
Spatial And Temporal Patterns ◽  
Reporter System ◽  
Fluorescent Reporter ◽  
Promoter Specificity ◽  
Reporter Transgene

Enhancers activate gene transcription in spatial and temporal patterns by interactions with gene promoters. These elements typically reside distal to their target promoter, with which they must interact selectively. Additional elements may contribute to enhancer-promoter specificity, including remote control element sequences within enhancers, tethering elements near promoters, and insulator/boundary elements that disrupt off-target interactions. However, few of these elements have been mapped, and as a result, the mechanisms by which these elements interact remain poorly understood. One impediment is their method of study, namely reporter transgenes in which enhancers are placed adjacent to a heterologous promoter, which may circumvent mechanisms controlling enhancer-promoter specificity and long-range interactions. Here, we report an optimized dual reporter transgene system in Drosophila melanogaster that allows the simultaneous comparison of an enhancer’s ability to activate proximal and distal fluorescent reporter genes. Testing a panel of fluorescent transgenes in vivo, we found a two-protein combination that allows simultaneous measurement with minimal detection interference. We note differences among four tested enhancers in their ability to regulate a distally placed reporter transgene. These results suggest that enhancers differ in their requirements for promoter interaction and raise important practical considerations when studying enhancer function.

scholarly journals Selective depletion of Foxp3+ regulatory T cells induces a scurfy-like disease

2007 ◽  
Vol 204 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Katharina Lahl ◽  
Christoph Loddenkemper ◽  
Cathy Drouin ◽  
Jennifer Freyer ◽  
Jon Arnason ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Fluorescent Protein ◽  
Early Death ◽  
Artificial Chromosome ◽  
Skin Inflammation ◽  
Lymphoproliferative Disease ◽  
Control Element ◽  
Protein Fusion

The scurfy mutant mouse strain suffers from a fatal lymphoproliferative disease leading to early death within 3–4 wk of age. A frame-shift mutation of the forkhead box transcription factor Foxp3 has been identified as the molecular cause of this multiorgan autoimmune disease. Foxp3 is a central control element in the development and function of regulatory T cells (T reg cells), which are necessary for the maintenance of self-tolerance. However, it is unclear whether dysfunction or a lack of T reg cells is etiologically involved in scurfy pathogenesis and its human correlate, the IPEX syndrome. We describe the generation of bacterial artificial chromosome–transgenic mice termed “depletion of regulatory T cell” (DEREG) mice expressing a diphtheria toxin (DT) receptor–enhanced green fluorescent protein fusion protein under the control of the foxp3 gene locus, allowing selective and efficient depletion of Foxp3+ T reg cells by DT injection. Ablation of Foxp3+ T reg cells in newborn DEREG mice led to the development of scurfy-like symptoms with splenomegaly, lymphadenopathy, insulitis, and severe skin inflammation. Thus, these data provide experimental evidence that the absence of Foxp3+ T reg cells is indeed sufficient to induce a scurfy-like phenotype. Furthermore, DEREG mice will allow a more precise definition of the function of Foxp3+ T reg cells in immune reactions in vivo.

Abstract 38: Rbp-j Regulates the Genetic Program of the Myo-epithelioid JG Cell

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Ruth M Castellanos Rivera ◽  
Ellen S. Pentz ◽  
Kenneth W. Gross ◽  
Silvia Medrano ◽  
Jing Yu ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Fluorescent Protein ◽  
Smooth Muscle Actin ◽  
Artificial Chromosome ◽  
Specific Protein ◽  
Genetic Program ◽  
Cell Phenotype ◽  
Gfp Expression ◽  
Renin Gene

RBP-J , the major downstream effector of Notch signaling, is necessary to maintain the number of juxtaglomerular (JG) cells. In addition, RBP-J regulates the plasticity of arteriolar smooth muscle cells to adopt the renin cell phenotype when homeostasis is threatened. We hypothesized that RBP-J acts as an on/off switch controlling the expression of genes that determine the renin phenotype. To determine whether RBP-J directly affects renin gene expression, we generated mice harboring a bacterial artificial chromosome (BAC) transgene with green fluorescent protein (GFP) under the control of the renin gene carrying a mutation in its RBP-J- binding site (Mut-BAC). Mut-BAC mice had markedly reduced GFP expression to 12.9 % ±0.01 (n=3) of the control (Wt-BAC) and a diminished response to homeostatic challenges: mut-BAC mice had a reduced number of GFP positive JG areas per total number of glomeruli (Wt-BAC: 25.1 % ±3.0, n=3; Mut-BAC: 9.3 % ±1.4, n=2, p<0.02) and no GFP expression along the arterioles. To determine whether the decrease in the number of JG cells in mice lacking RBP-J (cKO) was due to a diminished endowment of renin progenitor cells, we traced the fate of cells derived from the renin lineage by generating mice ( RBP-J fl/fl ; Ren1d +/cre ; R26R +/- ) in which cells lacking RBP-J simultaneously expressed β-galactosidase (β-gal). The pattern of β-gal in cKO and control kidneys was identical, indicating that cells derived from the renin lineage did not die but instead changed their phenotype. Next we investigated the phenotype adopted by the cells derived from the renin lineage. Expression of α-smooth muscle actin and smoothelin (a marker of mature smooth muscle) was significantly decreased to 41 % ±7.0 (n=2) and 44 % ±8.8 (n=2) respectively with respect to controls (p<0.01). In addition, mutant JG cells in vivo did not express genes characteristic of the renin phenotype such as renin, calponin1, Nfat and Akr1b7 expressing instead fibroblast-specific protein 1 indicating the adoption of a fibroblast-like phenotype. Results indicate that RBP-J directly governs a genetic program that controls the dual endocrine-contractile phenotype of the JG cell, which is crucial to maintain blood pressure and fluid-electrolyte homeostasis.

scholarly journals Intra-testicular injection of adenoviral constructs results in Sertoli cell-specific gene expression and disruption of the seminiferous epithelium

Reproduction ◽  
2009 ◽  
Vol 137 (2) ◽  
pp. 361-370 ◽  
Author(s):  
R P Hooley ◽  
M Paterson ◽  
P Brown ◽  
K Kerr ◽  
P T K Saunders
Keyword(s):  
Seminiferous Tubule ◽  
Fluorescent Protein ◽  
Immune Cell ◽  
Adenoviral Vectors ◽  
Seminiferous Tubules ◽  
Specific Gene ◽  
Viral Particles ◽  
Junctional Complexes ◽  
Testicular Injection

Spermatogenesis is a complex process that cannot be modelledin vitro. The somatic Sertoli cells (SCs) within the seminiferous tubules perform a key role in supporting maturation of germ cells (GCs). Progress has been made in determining what aspects of SC function are critical to maintenance of fertility by developing rodent models based on the Cre/LoxP system; however, this is time-consuming and is only applicable to mice. The aim of the present study was to establish methods for direct injection of adenoviral vectors containing shRNA constructs into the testis as a way of inducing target-selective knock-downin vivo. We describe here a series of experiments using adenovirus expressing a green fluorescent protein (GFP) transgene. Injection via the efferent ductules resulted in SC-specific expression of GFP; expression levels paralleled the amount of infective viral particles injected. At the highest doses of virus seminiferous tubule architecture were grossly disturbed and immune cell invasion noted. At lower concentrations, the expression of GFP was variable/negligible, the seminiferous tubule lumen was maintained but stage-dependent GC loss and development of numerous basal vacuoles was observed. These resembled intercellular dilations of SC junctional complexes previously described in rats and may be a consequence of disturbances in SC function due to interaction of the viral particles with the coxsackie/adenovirus receptor that is a component of the junctional complexes within the blood testis barrier. In conclusion, intra-testicular injection of adenoviral vectors disturbs SC functionin vivoand future work will therefore focus on the use of lentiviral delivery systems.

scholarly journals Developmental control of transcription of a retina-specific gene, QR1, during differentiation: involvement of factors from the POU family.

1995 ◽  
Vol 15 (2) ◽  
pp. 642-652 ◽  
Author(s):  
A Pierani ◽  
C Pouponnot ◽  
G Calothy
Keyword(s):  
Transcriptional Control ◽  
Growth Regulation ◽  
Late Phase ◽  
Regulatory Region ◽  
Neural Retina ◽  
Specific Gene ◽  
Postnatal Life ◽  
Developmental Control ◽  
Control Of Gene Expression

Developmental control of gene expression often results from the coupling of growth arrest with the establishment of differentiation programs. QR1 is a gene specifically expressed in retinas during the late phase of embryogenesis. At this stage neuroectodermal precursors have reached terminal mitosis and are undergoing differentiation into distinct cell types. Transcription of the QR1 gene is tightly regulated during retinal development: this gene is expressed between embryonic day 9 (ED9) and ED17 and is completely repressed at hatching in quail. Moreover, QR1 transcription is downregulated when postmitotic neural retina cells are induced to proliferate by pp60v-src. We studied the stage-dependent transcriptional control of this gene during quail neural retina (QNR) cell development. Transient transfection experiments with QR1/CAT constructs at various stages of development showed that a region located between -935 and -1265 bp upstream of the transcription start site is necessary to promote transcription in retina cells during the late phase of embryonal development (QNR9, corresponding to ED9). By in vivo footprinting assays we identified at least two elements that are occupied by DNA-protein complexes in QNR cells: the A and B boxes. The A box allows formation of several biochemically distinct complexes: C1, C2, C3, and C4. Formation of the C2 complex mainly during early stages (ED7) and of C2, C3, and C4 complexes during postnatal life correlates with repression of QR1 transcription, whereas the C1 complex is strongly induced at ED11 when the QR1 gene is expressed. We previously showed that C1 was involved in downregulation of QR1 transcription by pp60v-src. Several complexes are also formed on the B box. We show that these complexes are exclusively present in neural tissues and that they involve members of the POU family of transcription factors. Mutations of each one of the two regions which abolish the binding of the C1 factor(s) on the A box and of the POU factor(s) on the B box also prevent stimulation of QR1 transcription in QNR9. Therefore, both elements appear to be required for the stage-specific transcription of the QR1 gene. We also show that the regulatory region from position -1265 to position -935 is able to confer stage-specific transcription upon a heterologous promoter (thymidine kinase). Indeed, this region stimulates transcription in differentiating retinas (QNR9) and represses transcription in terminally differentiated retinas (QNR17, corresponding to postnatal life). Our results suggest that cell growth regulation and developmental control are coordinated through the A and B boxes in regulating QR1 transcription during retinal differentiation.

scholarly journals A Critical Review of Electroporation as A Plasmid Delivery System in Mouse Skeletal Muscle

2019 ◽  
Vol 20 (11) ◽  
pp. 2776 ◽  
Author(s):  
Emilia Sokołowska ◽  
Agnieszka Urszula Błachnio-Zabielska
Keyword(s):  
Skeletal Muscle ◽  
Fluorescent Protein ◽  
Physical Method ◽  
Specific Gene ◽  
Naked Dna ◽  
Advantages And Disadvantages ◽  
Electrical Pulses ◽  
Plasmid Injection ◽  
Green Fluorescent ◽  
Plasmid Delivery

The gene delivery to skeletal muscles is a promising strategy for the treatment of both muscular disorders (by silencing or overexpression of specific gene) and systemic secretion of therapeutic proteins. The use of a physical method like electroporation with plate or needle electrodes facilitates long-lasting gene silencing in situ. It has been reported that electroporation enhances the expression of the naked DNA gene in the skeletal muscle up to 100 times and decreases the changeability of the intramuscular expression. Coelectransfer of reporter genes such as green fluorescent protein (GFP), luciferase or beta-galactosidase allows the observation of correctly performed silencing in the muscles. Appropriate selection of plasmid injection volume and concentration, as well as electrotransfer parameters, such as the voltage, the length and the number of electrical pulses do not cause long-term damage to myocytes. In this review, we summarized the electroporation methodology as well as the procedure of electrotransfer to the gastrocnemius, tibialis, soleus and foot muscles and compare their advantages and disadvantages.

scholarly journals In vivo analysis of key elements within the renin regulatory region

2008 ◽  
Vol 35 (3) ◽  
pp. 243-253 ◽  
Author(s):  
Sean T. Glenn ◽  
Craig A. Jones ◽  
Li Pan ◽  
Kenneth W. Gross
Keyword(s):  
Fluorescent Protein ◽  
Regulatory Region ◽  
Renin Angiotensin System ◽  
Artificial Chromosome ◽  
Proximal Promoter ◽  
Gfp Expression ◽  
Renin Gene ◽  
Green Fluorescent

Renin is responsible for initiating the enzymatic cascade that results in the production of angiotensin II, the major effector molecule of the renin-angiotensin system (RAS). Extensive information on the regulatory region of the renin gene has been derived by transient transfection studies in vitro, particularly using the As4.1 cell line. To verify key factors within the regulatory region of renin in vivo, homologous recombination was used to introduce a green fluorescent protein (GFP) cassette into exon one of the renin gene contained within a 240 kb bacterial artificial chromosome (BAC) to create a construct that has GFP expression controlled by the renin regulatory region (RenGFP BAC). Within the regulatory region of the RenGFP BAC construct we independently deleted the enhancer, as well as mutated the HOX-PBX site within the proximal promoter element. Transgenic lines were generated for each of these BAC constructs and GFP expression was analyzed throughout a spectrum of tissues positive for renin expression including the kidney, adrenal gland, gonadal artery, and submandibular gland. The results described within this manuscript support the interpretation that the renin enhancer is critical for regulating baseline expression where as the Hox/Pbx site is important for the tissue specificity of renin expression.

Muscle electrotransfer as a tool for studying muscle fiber-specific and nerve-dependent activity of promoters

2003 ◽  
Vol 285 (5) ◽  
pp. C1071-C1081 ◽  
Author(s):  
Anne Bertrand ◽  
Valérie Ngô-Muller ◽  
Danièle Hentzen ◽  
Jean-Paul Concordet ◽  
Dominique Daegelen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transgene Expression ◽  
Muscle Physiology ◽  
Specific Gene ◽  
Specific Expression ◽  
Promising Tool ◽  
Transient Activation ◽  
Efficient Delivery ◽  
Optimized Conditions

Muscle electrotransfer has recently become a promising tool for efficient delivery of plasmids and transgene expression in skeletal muscle. This technology has been mainly applied to use of muscle as a bioreactor for production of therapeutic proteins. However, it remains to be determined whether muscle electrotransfer may also be accurately used as an alternative tool to transgenesis for studying aspects of muscle-specific gene control that must be explored in fully mature muscle fibers in vivo, such as fiber specificity and nerve dependence. It was also not known to what extent the initial electrical stimulations alter muscle physiology and gene expression. Therefore, optimized conditions of skeletal muscle electroporation were first tested for their effects on muscles of transgenic mice harboring a pM310-CAT transgene in which the CAT reporter gene was under control of the fast IIB fiber-specific and nerve-dependent aldolase A pM promoter. Surprisingly, electrostimulation led to a drastic but transient shutdown of pM310-CAT transgene expression concomitant with very transient activation of MyoD and, mostly, with activation of myogenin, suggesting profound alterations in transcriptional status of the electroporated muscle. Return to a normal transcriptional state was observed 7-10 days after electroporation. Therefore, we investigated whether a reporter construct placed under control of pM could exhibit fiber-specific expression 10 days after electrotransfer in either fast tibialis anterior or slow soleus muscle. We show that not only fiber specificity, but also nerve dependence, of a pM-driven construct can be reproduced. However, after electrotransfer, pM displayed a less tight control than previously observed for the same promoter when integrated in a chromatin context.

scholarly journals OTX5 Regulates Pineal Expression of the Zebrafish REV-ERBα through a New DNA Binding Site

2008 ◽  
Vol 22 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Shin-ichi Nishio ◽  
Tomoko Kakizawa ◽  
Gilles Chatelain ◽  
Gérard Triqueneaux ◽  
Frédéric Brunet ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Binding Site ◽  
Fluorescent Protein ◽  
Specific Gene ◽  
Orphan Nuclear Receptor ◽  
Cis Acting ◽  
Lower Vertebrates ◽  
Green Fluorescent ◽  
Zebrafish Embryogenesis

Abstract The pineal gland plays a central role in the photoneuroendocrine system and acts as a photosensory organ in lower vertebrates. The orphan nuclear receptor Rev-erbα (NR1D1) has previously been shown to be expressed in the pineal and to be regulated with a robust circadian rhythm during zebrafish embryogenesis. This early pineal expression is under the control of the transcription factor Orthodenticle homeobox 5 (Otx5). In this paper, we show that Otx5 regulates the second zfRev-erbα promoter, ZfP2. Despite the absence of a classical Otx-binding site within ZfP2, this regulation depends on the integrity of the Otx5 homeodomain. Mapping experiments as well as EMSAs show that this interaction between Otx5 and ZfP2 depends on a noncanonical bipartite Otx-binding site (GANNCTTA and TAAA) that we called pineal expression related element (PERE). We showed that PERE is necessary for pineal expression in vivo by injecting zebrafish embryos with wild type and mutated versions of zfRev-erbα promoter fused to green fluorescent protein. Interestingly, PERE is found upstream of other genes expressed in the pineal gland, suggesting that it may play an important role in governing pineal expression. Our data establish that PERE is a novel cis-acting element contributing to pineal-specific gene expression and to Otx target gene regulation.

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