Search results for "DOWN-REGULATION"
showing 10 items of 310 documents
Down-regulation of nuclear binding activities of OXBOX-REBOX transcription factors during cellular senescence.
1996
Functional capacity of mitochondria declines during aging and this impairment may have a major role in aging process. Several observations indicate that transcriptional efficiency is reduced during aging. Our purpose was to find out whether aging and cellular senescence affect the nuclear binding activities of transcription factors which bind to OXBOX-REBOX sequence present in promoter regions of numerous nuclear genes encoding mitochondrial proteins. These factors regulate and coordinate the expression of mitochondrial proteins. We observed a strong down-regulation in the nuclear binding activities of OXBOX-REBOX factors in replicatively senesced human WI-38 and IMR-90 fibroblasts. On the …
MicroRNAs: Promising New Antiangiogenic Targets in Cancer
2014
[EN] MicroRNAs are one class of small, endogenous, non-coding RNAs that are approximately 22 nucleotides in length; they are very numerous, have been phylogenetically conserved, and involved in biological processes such as development, differentiation, cell proliferation, and apoptosis. MicroRNAs contribute to modulating the expression levels of specific proteins based on sequence complementarity with their target mRNA molecules and so they play a key role in both health and disease. Angiogenesis is the process of new blood vessel formation from preexisting ones, which is particularly relevant to cancer and its progression. Over the last few years, microRNAs have emerged as critical regulat…
Caveolin and GLT-1 gene expression is reciprocally regulated in primary astrocytes: Association of GLT-1 with non-caveolar lipid rafts
2004
Caveolae represent membrane microdomains acting as integrators of cellular signaling and functional processes. Caveolins are involved in the biogenesis of caveolae and regulate the activity of caveolae-associated proteins. Although caveolin proteins are found in the CNS, the regulation of caveolins in neural cells is poorly described. In the present study, we investigated different modes and mechanisms of caveolin gene regulation in primary rat astrocytes. We demonstrated that activation of cAMP-dependent signaling pathways led to a marked reduction in protein levels of caveolin-1/-2 in cortical astrocytes. Application of transforming growth factor-alpha (TGF-alpha) also resulted in a decre…
A critical role for Cyclin E in cell fate determination in the central nervous system of Drosophila melanogaster
2004
We have examined the process by which cell diversity is generated in neuroblast (NB) lineages in the central nervous system of Drosophila melanogaster. Thoracic NB6-4 (NB6-4t) generates both neurons and glial cells, whereas NB6-4a generates only glial cells in abdominal segments. This is attributed to an asymmetric first division of NB6-4t, localizing prospero (pros) and glial cell missing (gcm) only to the glial precursor cell, and a symmetric division of NB6-4a, where both daughter cells express pros and gcm. Here we show that the NB6-4t lineage represents the ground state, which does not require the input of any homeotic gene, whereas the NB6-4a lineage is specified by the homeotic genes…
Comm Sorts Robo to Control Axon Guidance at the Drosophila Midline
2002
AbstractAxon growth across the Drosophila midline requires Comm to downregulate Robo, the receptor for the midline repellent Slit. We show here that comm is required in neurons, not in midline cells as previously thought, and that it is expressed specifically and transiently in commissural neurons. Comm acts as a sorting receptor for Robo, diverting it from the synthetic to the late endocytic pathway. A conserved cytoplasmic LPSY motif is required for endosomal sorting of Comm in vitro and for Comm to downregulate Robo and promote midline crossing in vivo. Axon traffic at the CNS midline is thus controlled by the intracellular trafficking of the Robo guidance receptor, which in turn depends…
Influenza A virus infection inhibits the efficient recruitment of Th2 cells into the airways and the development of airway eosinophilia.
2003
Abstract Most infections with respiratory viruses induce Th1 responses characterized by the generation of Th1 and CD8+ T cells secreting IFN-γ, which in turn have been shown to inhibit the development of Th2 cells. Therefore, it could be expected that respiratory viral infections mediate protection against asthma. However, the opposite seems to be true, because viral infections are often associated with the exacerbation of asthma. For this reason, we investigated what effect an influenza A (flu) virus infection has on the development of asthma. We found that flu infection 1, 3, 6, or 9 wk before allergen airway challenge resulted in a strong suppression of allergen-induced airway eosinophil…
Down-regulation of early sea urchin histone H2A gene relies on cis regulative sequences located in the 5' and 3' regions and including the enhancer b…
2004
The tandem repeated sea urchin alpha-histone genes are developmentally regulated by gene-specific promoter elements. Coordinate transcription of the five genes begins after meiotic maturation of the oocyte, continues through cleavage, and reaches its maximum at morula stage, after which these genes are shut off and maintained in a silenced state for the life cycle of the animal. Although cis regulative sequences affecting the timing and the level of expression of these genes have been characterized, much less is known about the mechanism of their repression. Here we report the results of a functional analysis that allowed the identification of the sequence elements needed for the silencing …
Down-regulation of transcription factors AP-1, Sp-1, and NF-kappa B precedes myocyte differentiation.
1996
Terminal differentiation of myocytes involves withdrawal from the cell cycle, induction of myogenin expression, and finally formation of myotubes. To study the factors that regulate the initial phase of muscle differentiation, we analyzed the binding activities of transcription factors AP-1, Sp-1, and NF-kappa B in L6, C2C12, and rhabdomyosarcoma BA-Han-1C cells. Temporal changes in transcription factor binding activities were compared to the activation of myogenin promoter-driven CAT reporter gene and the expression level of myogenin, a master gene of myogenic differentiation. We observed a prominent decrease in the nuclear binding activities of AP-1, Sp-1, and NF-kappa B already 12 to 24 …
p53-Mediated downregulation of H ferritin promoter transcriptional efficiency via NF-Y.
2008
The tumor suppressor protein p53 triggers many of the cellular responses to DNA damage by regulating the transcription of a series of downstream target genes. p53 acts on the promoter of the target genes by interacting with the trimeric transcription factor NF-Y. H ferritin promoter activity is tightly dependent on a multiprotein complex called Bbf; on this complex NF-Y plays a major role. The aim of this work was to study the modulation of H ferritin expression levels by p53. CAT reporter assays indicate that: (i) p53 overexpression strongly downregulates the transcriptional efficiency driven by an H ferritin promoter construct containing only the NF-Y recognition sequence and that the phe…
Endoplasmic reticulum‐resident chaperones modulate the inflammatory and angiogenic responses of endothelial cells
2015
SummaryBackground Wound healing depends on a well-balanced regulation of inflammation and angiogenesis. In chronic wounds the healing process is disturbed and inflammation persists. Regulation of wound closure is controlled by transmembrane and extracellular proteins, the folding and maturation of which occur in the endoplasmic reticulum (ER) by ER-resident chaperone machinery. Objectives To study the role of the ER-resident chaperones BiP/Grp78, its cochaperone Mdg1/ERdJ4, and Grp94 in chronic, nonhealing wounds. Methods Immunohistochemical staining of these chaperones in individual human biopsies and investigation of the possible role of BiP and Mdg1 in endothelial cells, focusing on thei…