Search results for "Repo"
showing 10 items of 2753 documents
A novel SP-1 site in the human interleukin-1β promoter confers preferential transcriptional activity in keratinocytes
1996
To investigate the mechanisms of transcriptional activation of interleukin-1beta (IL-1beta) in non-monocytic cells, we constructed a series of reporter plasmids with the bacterial chloramphenicol acetyltransferase gene linked to various parts of the human IL-1beta promoter and performed transient transfection experiments. We identified a promoter segment that activates transcription most efficiently in keratinocytes. Electrophoretic mobility shift assays (EMSA) with a 43-mer oligonucleotide derived from the functionally identified cis-acting element revealed specific complexes. By competition analysis with transcription factor consensus sequence oligonucleotides and by immunosupershift, tra…
A GFP-tagged Muscleblind C protein isoform reporter construct
2010
Drosophila muscleblind (mbl), the ortholog of human Muscleblind-like 1 (MBNL1) gene involved in Myotonic Dystrophy (DM), gives raise to protein isoforms MblA to G. The specific functions and subcellular distribution of isoforms are still largely unknown. To overcome the lack of isoform-specific antibodies we generated transgenic flies that express a GFP:MblC fusion protein under the control of the Gal4/UAS system. The reporter fusion protein was able to functionally complement mbl loss of function mutations, demonstrating activity, and accumulated predominantly in adult muscle nuclei. The fluorescent nature of the reporter makes it appropriate for live imaging detection of MblC protein isof…
TGF-β superfamily signaling is essential for tooth and hair morphogenesis and differentiation
2007
Members of the transforming growth factor beta (TGF-beta) superfamily of signaling molecules are involved in the regulation of many developmental processes that involve the interaction between mesenchymal and epithelial tissues. Smad7 is a potent inhibitor of many members of the TGF-beta family, notably TGF-beta and activin. In this study, we show that embryonic overexpression of Smad7 in stratified epithelia using a keratin 5 promoter, results in severe morphogenetic defects in skin and teeth and leads to embryonic and perinatal lethality. To further analyze the functions of Smad7 in epithelial tissues of adult mice, we used an expression system that allowed a controlled overexpression of …
Differential expression levels of Sox9 in early neocortical radial glial cells regulate the decision between stem cell maintenance and differentiation
2021
ABSTRACTRadial glial progenitor cells (RGCs) in the dorsal forebrain directly or indirectly produce excitatory projection neurons and macroglia of the neocortex. Recent evidence shows that the pool of RGCs is more heterogeneous than originally thought and that progenitor subpopulations can generate particular neuronal cell types. Using single cell RNA sequencing, we have studied gene expression patterns of two subtypes of RGCs that differ in their neurogenic behavior. One progenitor type rapidly produces postmitotic neurons, whereas the second progenitor remains relatively quiescence before generating neurons. We have identified candidate genes that are differentially expressed between thes…
Collective Viral Spread Mediated by Virion Aggregates Promotes the Evolution of Defective Interfering Particles
2020
Recent insights have revealed that viruses use a highly diverse set of strategies to release multiple viral genomes into the same target cells, allowing the emergence of beneficial, but also detrimental, interactions among viruses inside infected cells. This has prompted interest among microbial ecologists and evolutionary biologists in studying how collective dispersal impacts the outcome of viral infections. Here, we have used vesicular stomatitis virus as a model system to study the evolutionary implications of collective dissemination mediated by viral aggregates, since this virus can spontaneously aggregate in the presence of saliva. We find that saliva-driven aggregation has a dual ef…
Compartmentalization of Central Neurons inDrosophila: A New Strategy of Mosaic Analysis Reveals Localization of Presynaptic Sites to Specific Segment…
2002
Synaptogenesis in the CNS has received far less attention than the development of neuromuscular synapses, although only central synapses allow the study of neuronal postsynaptic mechanisms and display a greater variety of structural and functional features. This neglect is attributable mainly to the enormous complexity of the CNS, which makes the visualization of individual synapses on defined neuronal processes very difficult. We overcome this obstacle and demonstrate by confocal microscopy the specific arrangement of output synapses on individual neurites. These studies are performed via genetic mosaic strategies in the CNS of the fruitfly Drosophila melanogaster. First, we use targeted e…
The commonly used marker ELAV is transiently expressed in neuroblasts and glial cells in theDrosophilaembryonic CNS
2007
Glial cells in the Drosophila embryonic nervous system can be monitored with the marker Reversed-polarity (Repo), whereas neurons lack Repo and express the RNA-binding protein ELAV (Embryonic Lethal, Abnormal Vision). Since the first description of the ELAV protein distribution in 1991 (Robinow and White), it is believed that ELAV is an exclusive neuronal and postmitotic marker. Looking at ELAV expression, we unexpectedly observed that, in addition to neurons, ELAV is transiently expressed in embryonic glial cells. Furthermore, it is transiently present in the proliferating longitudinal glioblast, and it is transcribed in embryonic neuroblasts. Likewise, elav-Gal4 lines, which are generally…
GAL4-responsive UAS- tau as a tool for studying the anatomy and development of the Drosophila central nervous system
1997
To improve the quality of cytoplasmic labelling of GAL4-expressing cells in Drosophila enhancer-trap and transgenic strains, a new GAL4-responsive reporter UAS-tau, which features a bovine tau cDNA under control of a yeast upstream activation sequence (UAS), was tested. Tau, a microtubule-associated protein, is distributed actively and evenly into all cellular processes. Monoclonal anti-bovine Tau antibody reveals the axonal structure of the labelled cells with detail similar to that of Golgi impregnation. We demonstrate that the UAS-tau system is especially useful for studying processes of differentiation and reorganisation of identified neurones during postembryonic development.
Two Enhancers Control Transcription of Drosophila muscleblind in the Embryonic Somatic Musculature and in the Central Nervous System
2014
The phylogenetically conserved family of Muscleblind proteins are RNA-binding factors involved in a variety of gene expression processes including alternative splicing regulation, RNA stability and subcellular localization, and miRNA biogenesis, which typically contribute to cell-type specific differentiation. In humans, sequestration of Muscleblind-like proteins MBNL1 and MBNL2 has been implicated in degenerative disorders, particularly expansion diseases such as myotonic dystrophy type 1 and 2. Drosophila muscleblind was previously shown to be expressed in embryonic somatic and visceral muscle subtypes, and in the central nervous system, and to depend on Mef2 for transcriptional activatio…
Acute Respiratory Distress Syndrome Associated with Tumor Lysis Syndrome in a Child with Acute Lymphoblastic Leukemia
2015
Tumor lysis syndrome is a serious and dangerous complication usually associated with antiblastic treatment in some malignancies characterized by high cell turn-over. Mild or severe electrolyte abnormalities including high serum levels of uric acid, potassium, phosphorus, creatinine, bun and reduction of calcium can be responsible for multi-organ failure, involving mostly kidneys, heart and central nervous system. Renal damage can be followed by acute renal failure, weight gain, progressive liver impairment, overproduction of cytokines, and subsequent maintenance of multi-organ damage. Life-threatening acute respiratory failure associated with tumor lysis syndrome is rare. We describe a chil…