Search results for "Reporter"
showing 10 items of 166 documents
Alternative Polyadenylation Events Contribute to the Induction of NF-ATc in Effector T Cells
1999
Abstract The transcription factor NF-ATc is synthesized in three prominent isoforms. These differ in the length of their C terminal peptides and mode of synthesis. Due to a switch from the use of a 3′ polyA site to a more proximal polyA site, NF-ATc expression switches from the synthesis of the two longer isoforms in naive T cells to that of short isoform A in T effector cells. The relative low binding affinity of cleavage stimulation factor CstF-64 to the proximal polyA site seems to contribute to its neglect in naive T cells. These alternative polyadenylation events ensure the rapid accumulation of high concentrations of NF-ATc necessary to exceed critical threshold levels of NF-ATc for g…
Sterol Regulatory Element-binding Protein-1c Is Responsible for Cholesterol Regulation of Ileal Bile Acid-binding Protein Gene in Vivo
2002
Ileal bile acid-binding protein (I-BABP) is a cytosolic protein that binds bile acid (BA) specifically. In the ileum, it is thought to be implied in their enterohepatic circulation. Because the fecal excretion of BA represents the main physiological way of elimination for cholesterol (CS), the I-BABP gene could have a major function in CS homeostasis. Therefore, the I-BABP gene expression might be controlled by CS. I-BABP mRNA levels were significatively increased when the human enterocyte-like CaCo-2 cells were CS-deprived and repressed when CS were added to the medium. A highly conserved sterol regularory element-like sequence (SRE) and a putative GC box were found in human I-BABP gene pr…
Surmounting limited gene delivery into primary immune cell populations: Efficient cell type-specific adenoviral transduction by CAR.
2015
Ectopic gene expression studies in primary immune cells have been notoriously difficult to perform due to the limitations in conventional transfection and viral transduction methods. Although replication-defective adenoviruses provide an attractive alternative for gene delivery, their use has been hampered by the limited susceptibility of murine leukocytes to adenoviral infection, due to insufficient expression of the human coxsackie/adenovirus receptor (CAR). In this issue of the European Journal of Immunology, Heger et al. [Eur. J. Immunol. 2015. 45: XXXX-XXXX] report the generation of transgenic mice that enable conditional Cre/loxP-mediated expression of human CAR. The authors demonstra…
Conditional transgenic mouse models: from the basics to genome-wide sets of knockouts and current studies of tissue regeneration
2008
Many mouse models are currently available, providing avenues to elucidate gene function and to recapitulate specific pathological conditions. To a large extent, successful translation of clinical evidence or analytical data into appropriate mouse models is possible through progress in transgenic or gene-targeting technology. Beginning with a review of standard mouse transgenics and conventional gene targeting, this article will move on to discussing the basics of conditional gene expression: the tetracycline (tet)-off and tet-on systems based on the transactivators tet-controlled transactivator (Tta) and reverse tet-on transactivator (rtTA) that allow downregulation or induction of gene exp…
A stress-responsive miRNA regulates BMP signaling to maintain tissue homeostasis
2021
Adult organisms must sense and adapt to environmental fluctuations. In high-turnover tissues such as the intestine, these adaptive responses require rapid changes in gene expression that, in turn, likely involve posttranscriptional gene control. However, intestinal-tissue-specific microRNA (miRNA)-mediated regulatory pathways remain unexplored. Here, we report the role of an intestinal-specific miRNA, miR-958, that non-cell autonomously regulates stem cell numbers during tissue homeostasis and regeneration in the Drosophila adult midgut. We identify its downstream target cabut, the Drosophila ortholog of mammalian KLF10/11 transcription factors, which mediates this miR-958 function by promo…
Modulation of base excision repair of 8-oxoguanine by the nucleotide sequence.
2013
8-Oxoguanine (8-oxoG) is a major product of oxidative DNA damage, which induces replication errors and interferes with transcription. By varying the position of single 8-oxoG in a functional gene and manipulating the nucleotide sequence surrounding the lesion, we found that the degree of transcriptional inhibition is independent of the distance from the transcription start or the localization within the transcribed or the non-transcribed DNA strand. However, it is strongly dependent on the sequence context and also proportional to cellular expression of 8-oxoguanine DNA glycosylase (OGG1)-demonstrating that transcriptional arrest does not take place at unrepaired 8-oxoG and proving a causal…
8-Oxoguanine DNA glycosylase (Ogg1) causes a transcriptional inactivation of damaged DNA in the absence of functional Cockayne syndrome B (Csb) prote…
2008
We have analysed the effect of oxidative guanine lesions on the expression of a transfected reporter gene in mouse embryonic fibroblasts deficient in Cockayne syndrome B protein (Csb) and/or the 8-oxoguanine DNA glycosylase (Ogg1). We used a highly sensitive flow cytometry-based approach and quantitative real-time PCR to measure the changes in gene expression caused by the presence of oxidised guanine residues generated by photosensitisation in the vector DNA. In wild-type cells, small numbers (one or three) of oxidised guanines did not affect gene expression at short times after transfections, whereas progressive reduction of the transgene expression was observed at later time points. Alth…
Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2-dependent RNA granules.
2008
Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that…
Spatial shaping of cochlear innervation by temporally regulated neurotrophin expression.
2001
Previous work suggested qualitatively different effects of neurotrophin 3 (NT-3) in cochlear innervation patterning in different null mutants. We now show that all NT-3 null mutants have a similar phenotype and lose all neurons in the basal turn of the cochlea. To understand these longitudinal deficits in neurotrophin mutants, we have compared the development of the deficit in the NT-3 mutant to the spatial–temporal expression patterns of brain-derived neurotrophic factor (BDNF) and NT-3, using lacZ reporters in each gene and with expression of the specific neurotrophin receptors, trkB and trkC. In the NT-3 mutant, almost normal numbers of spiral ganglion neurons form, but fiber outgrowth t…
Dissection of keratin dynamics: different contributions of the actin and microtubule systems.
2005
It has only recently been recognized that intermediate filaments (IFs) and their assembly intermediates are highly motile cytoskeletal components with cell-type- and isotype-specific characteristics. To elucidate the cell-type-independent contribution of actin filaments and microtubules to these motile properties, fluorescent epithelial IF keratin polypeptides were introduced into non-epithelial, adrenal cortex-derived SW13 cells. Time-lapse fluorescence microscopy of stably transfected SW13 cell lines synthesizing fluorescent human keratin 8 and 18 chimeras HK8-CFP and HK18-YFP revealed extended filament networks that are entirely composed of transgene products and exhibit the same dynamic…