C Expression (c + expression)

Distribution by Scientific Domains
Medical Sciences33%

Selected Abstracts

DNase I hypersensitive sites and transcriptional activation of the lamin A/C gene

FEBS JOURNAL, Issue 5 2000
Kazuhiko Nakamachi
The lamin A/C gene encodes subtypes of nuclear lamins, which are involved in nuclear envelope formation, and was recently identified as the responsible gene for the autosomal dominant Emery,Dreifuss muscular dystrophy. Expression of the lamin A/C gene is developmentally regulated but little is known about the regulatory mechanism. Previous studies of lamin A/C expression suggested that the chromatin structure is important for the regulation of its expression. To elucidate the regulatory mechanism of the lamin A/C gene expression, we have analysed the functional region of the mouse lamin A/C promoter and the chromatin structure of the gene in terms of nucleosome structure and DNase I hypersensitivity. Our analyses revealed disruption of the nucleosome array at the promoter region and the presence of multiple DNase I hypersensitive sites (HSs) which were specifically associated with expression of the lamin A/C gene. Inclusion of a segment which contained the HSs in a lamin A/C promoter-luciferase reporter plasmid showed no effect on the transfected promoter activity in transient expression assays. On the other hand, substantial enhancement of the promoter activity was detected when the transfected DNA was stably integrated into the genome, suggesting the importance of the HSs in the regulation of lamin A/C expression. [source]

,2A and ,2C -adrenoceptor regulation in the brain: ,2A changes persist after chronic stress

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2003
G. Flügge
Abstract Stress-induced activation of the central nervous noradrenergic system has been suspected to induce depressive disorders. As episodes of depression often occur some time after a stress experience we investigated whether stress-induced changes in the ,2 -adrenoceptor (,2 -AR) system persist throughout a post-stress recovery period. Brains of male tree shrews were analysed after 44 days of chronic psychosocial stress and after a subsequent 10-day recovery period. Expression of RNA for ,2A and ,2C -adrenoceptors was quantified by in situ hybridization, and receptor binding was determined by in vitro receptor autoradiography. Activities of the sympathetic nervous system and of the hypothalamo,pituitary,adrenal axis were increased during chronic stress but normalized during recovery. ,2A -AR RNA in the glutamatergic neurons of the lateral reticular nucleus was elevated significantly after stress and after recovery (by 29% and 17%). In the dorsal motor nucleus of the vagus, subtype A expression was enhanced after recovery (by 33%). In the locus coeruleus, subtype A autoreceptor expression was not changed significantly. Subtype C expression in the caudate nucleus and putamen was elevated by stress (by 5 and 4%, respectively) but normalized during recovery. Quantification of 3H-RX821002 binding revealed receptor upregulation during stress and/or recovery. Our data therefore show: (i) that chronic psychosocial stress differentially regulates expression of ,2 -adrenoceptor subtypes A and C; (ii) that subtype A heteroreceptor expression is persistently upregulated whereas (iii), subtype C upregulation is only transient. The present findings coincide with post mortem studies in depressed patients revealing upregulation of ,2A -ARs. [source]

Regulated expression and intracellular localization of cystatin F in human U937 cells

FEBS JOURNAL, Issue 22 2002
Carl-Michael Nathanson
Cystatin F is a cysteine peptidase inhibitor recently discovered in haematopoietic cells by cDNA cloning. To further investigate the expression, distribution and properties of the native human inhibitor the promyeloid cell line U937 has been studied. The cells expressed relatively large quantities of cystatin F, which was found both secreted and intracellularly. The intracellular levels were unusually high for a secreted cystatin (, 25% of the cystatin F in 2- or 4-day culture medium). By contrast, U937 cells contained only 3,4% of the related inhibitor, cystatin C. Cystatin F purified from lysates of U937 cells showed three major forms carrying two, one or no carbohydrate chains. Immunocytochemistry demonstrated a marked cytoplasmic cystatin F staining in a granular pattern. Double staining with a marker for endoplasmic reticulum revealed no colocalization for cystatin F. Analysis of the promoter region of the cystatin F gene (CST7) showed that it, like that of the cystatin C gene (CST3), is devoid of typical TATA- and CAAT-box elements. In contrast to the cystatin C promoter, it does not contain multiple Sp1 binding sites, but has a unique site for C/EBP,, possibly explaining the restricted expression of the cystatin F gene. Cells stimulated with all- trans retinoic acid to differentiate them towards a granulocytic pathway, showed a strong (, 18-fold) down-regulation of intracellular cystatin F and almost abolished secreted levels of the inhibitor. Stimulation with tetradecanoyl phorbol acetate, causing monocytic differentiation, also resulted in down-regulation (two fold to threefold) of cystatin F expression, whereas the cystatin C expression was essentially unaltered in both experiments. The results suggest that cystatin F as an intracellular cysteine peptidase inhibitor with readily regulated expression, may be a candidate to control the cysteine peptidase activity known to be essential for antigen presentation in different blood cell lineages. [source]

Expression of interleukin 3 and granulocyte,macrophage colony-stimulating factor receptor common chain ,c, ,IT in normal haematopoiesis: lineage specificity and proliferation-independent induction

BRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2000
Stefania Militi
Interleukin 3 (IL-3), granulocyte,macrophage colony-stimulating factor (GM-CSF) and interleukin 5 (IL-5) exert their biological activities through interaction with cell-surface receptors that consist of two subunits, a specific , subunit and a common , transducing subunit (,c). We have evaluated the expression of ,c on purified haematopoietic progenitor cells (HPCs) induced to unilineage differentiation/maturation through the erythroid (E), granulocytic (G), megakaryocytic (Mk) or monocytic (Mo) lineage. HPCs displayed low ,c expression, which increased during the initial stages of HPC differentiation along the E, G, Mo or Mk lineages. At later stages of differentiation, ,c chain expression increased in both G and Mo lineages, was expressed at low levels in the Mk lineage and declined to undetectable levels in the E lineage. Analysis of the full-length ,c and intracytoplasmically truncated ,c (,IT) mRNAs showed that the former was predominant in the G and Mo lineages, whereas the latter was prevalent in the E and Mk lineages. The ,c induction takes place even in the absence of cell cycling. Thus, incubation of HPCs with graded amounts of IL-3 showed that the initial induction of ,c expression is unrelated to cell proliferation. Furthermore, circulating monocytes and granulocytes exhibit a low level of ,c expression that is greatly stimulated following incubation with either IL-3 or GM-CSF. [source]

Expression and structure of interleukin 4 receptors in primary meningeal tumors

CANCER, Issue 10 2005
Sachin Puri M.Sc.
Abstract BACKGROUND It was reported previously that malignant human tumors, like glioma and medulloblastoma, express high-density interleukin (IL-4) receptor mRNA and protein. Because IL-4 receptors (R) are sensitive targets for targeted therapeutics, knowledge of the expression of these receptors in other central nervous system tumors is of great interest. In this study, the authors examined the expression and subunit composition of IL-4R complex in primary human meningiomas. METHODS Reverse transcription-polymerase chain reaction (RT-PCR) analysis for IL-13R,1, IL-4R, and IL-2R,c was performed on total RNA extracted from 35 meningiomas and a normal human brain tissue sample. Results were confirmed in nine randomly selected tumors by quantitative real-time PCR and in situ immunofluorescence assay. RESULTS Transcripts for the IL-4R, and IL-13R,1 chains were overexpressed in meningiomas compared with normal brain tissue. The levels of IL-4R, mRNA appeared to be higher compared with the levels of IL-13R,1 mRNA. The results also showed that tumors with higher disease grade tended to have increased mRNA expression for the IL-4R, chain. This IL-4R, mRNA overexpression appeared to be more frequent in younger patients (age < 37 years). The transcripts for IL-2R,c chain were not detected in any of the tumor samples or in normal brain tissue. Quantitative real-time PCR confirmed the results of the RT-PCR analysis. Meningiomas also demonstrated a bright immunofluorescent staining for the IL-4R, and IL-13R,1 chains but no staining for IL-2R,c. CONCLUSIONS Expression of the IL-4R, and IL-13R,1 chains and absence of IL-2,c expression established that meningiomas expressed type II IL-4Rs. These receptors may serve as a target for cytotoxin/immunotoxin therapy in patients with meningioma who are not amenable to surgical resection or for recurrent tumors. Cancer 2005. © 2005 American Cancer Society. [source]

Altered expression of CCAAT/enhancer binding protein and FABP11 genes during adipogenesis in vitro in Atlantic salmon (Salmo salar)

AQUACULTURE NUTRITION, Issue 1 2010
T.-S. HUANG
Abstract The study of CCAAT/enhancer binding proteins (C/EBPs) is important in the understanding of adipogenesis, but little is known about their regulation in fish. Here, we report three Atlantic salmon orthologs of c/ebp, and their expression in different tissues and in adipogenesis in vitro. During differentiation the expression of c/ebp, and fatp1 were upregulated in early differentiation stage with continuing high expression level in mature adipocytes, whereas c/ebp, and fabp11 expression were elevated in mature adipocytes. Furthermore, the fatty acids eicosapentaenoic (EPA) and docosahexaenoic (DHA), suppressed the expression of the c/ebps, ppar,, and fatty acid transport protein (fatp1) during terminal adipocyte differentiation. The study indicates that C/EBPs are induced upon the differentiation of primary-cultured adipocytes from Atlantic salmon and that marine n-3 highly unsaturated fatty acids (HUFAs) affect the c/ebps expressions in mature adipocytes. Therefore, the established cell model described here appears to be valuable for studying modulation of fat content in farmed Atlantic salmon. [source]