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RNA Stabilization (rna + stabilization)
Selected AbstractsIL-1, induces stabilization of IL-8 mRNA in malignant breast cancer cells via the 3, untranslated region: Involvement of divergent RNA-binding factors HuR, KSRP and TIAR,INTERNATIONAL JOURNAL OF CANCER, Issue 6 2005Esther A. Suswam Abstract IL-8 plays an integral role in promoting the malignant phenotype in breast cancer, and its production is directly influenced by inflammatory cytokines in the tumor microenvironment. Here, we show that activation of IL-1, receptors on malignant HS578t and MDA-MB-231 breast cancer cells strongly induces IL-8 expression and that RNA stabilization is persistently activated at least 12,24 hr after stimulation. SB 203580 and rapamycin reversed the RNA stabilization effect of IL-1, in a dose-dependent manner, suggesting involvement of the p38/MAP kinase and mTOR pathways. A luciferase reporter assay indicated that the stabilization effect was dependent on cis elements in the 3,-untranslated region (UTR) of the IL-8 transcript. By UV cross-linking, we identified multiple cellular factors that interact with the IL-8 3,UTR, ranging 34,76 kDa. Immunoprecipitation analysis indicated that HuR, KSRP and TIAR bound to one or more loci in the 3,UTR. While the cross-linking patterns were similar, quantitative immunoprecipitation of native IL-8 RNA from IL-1,-stimulated cytoplasmic extract revealed a 20-fold greater association of transcript with the stabilizing factor HuR vs. the destabilizing factor KSRP. In conclusion, IL-1, is a potent cytokine stimulus for IL-8 RNA stabilization in breast cancer cells, possibly by enhanced binding of cytoplasmic HuR to the 3,UTR. Published 2004 Wiley-Liss, Inc. [source] AUF1 and Hu proteins in the developing rat brain: Implication in the proliferation and differentiation of neural progenitorsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2009Dolores Hambardzumyan Abstract Posttranscriptional events such as RNA stabilization are important for cell differentiation, but little is known about the impact of AU-rich binding proteins (AUBPs) on the fate of neural cells. Expression of destabilizing AUBPs such as AUF1 and neuronal-specific stabilizing proteins such as HuB, HuC and HuD was therefore analyzed in the developing central nervous system. Real-time RT-PCR indicated a specific developmental pattern in the postnatal cerebellum, with a progressive down-regulation of AUF1 from P1, whereas HuB was strongly up-regulated at about P7. These changes were accompanied by a progressive increase in AUF1p45 and the disappearance of one HuB isoform from P15, suggesting particular roles for these AUBPs in the developing cerebellum. AUF1 was detected in the three main cerebellar layers, whereas Hu proteins were found only in postmitotic neurons. A role for Hu proteins in the early stages of neuronal differentiation is further supported by arrest of cell proliferation following induction of HuB or HuD expression in a neural stem cell line. The decrease in nestin expression suggest that HuD, but not HuB, favors the transition of neural progenitors into early neuroblasts, but other factors are most probably required for their full differentiation into neurons, insofar as GAP-43 was not detected in HuD-transfected cells. These data suggest critical roles for HuB at the very earliest stages of neuronal differentiation, such as cell cycle exit, and HuD might also be involved in the transition of neural progenitors into early neuroblasts. Taken together, the present results strengthen the importance of AUBPs in brain ontogenesis. © 2008 Wiley-Liss, Inc. [source] Post-translational modifications, but not transcriptional regulation, of major chloroplast RNA-binding proteins are related to Arabidopsis seedling developmentPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2006Bai-Chen Wang Abstract Chloroplast RNA-binding proteins are involved in stabilizing stored chloroplast mRNAs and in recruiting site-specific factors that mediate RNA metabolism. In the present study, we characterized two major chloroplast RNA-binding proteins, cp29A and cp29B, by MALDI-TOF MS, N-terminal sequencing, and ESI-MS/MS following 2D-PAGE separation. Polypeptides derived from cp29A were recovered with free N-terminus or with N-terminal acetylation. In addition to the two isoforms found for cp29A, an isoform derived from cp29B was also observed to have five amino acids cleaved from its N-terminus. Results of quantitative real-time RT-PCR indicate that both genes reached maximal rates of transcription 96,h after commencement of germination and maintained relatively high levels throughout the whole life cycle. Transcription of cp29A and cp29B did not vary significantly under light or dark conditions, although production of the acetylated and N-terminally cleaved protein isoforms exhibited light dependence. Exposure of etiolated Arabidopsis seedlings to light conditions for as short as 9,h restored the modified isoforms to levels similar to those found in green plants. Identification of post-translational modifications in major chloroplast RNA-binding proteins may help elucidate their roles in seedling development and in plant RNA stabilization during the greening process. [source] Resistin induces expression of proinflammatory cytokines and chemokines in human articular chondrocytes via transcription and messenger RNA stabilizationARTHRITIS & RHEUMATISM, Issue 7 2010Zhiqi Zhang Objective To elucidate the effects of resistin on human articular chondrocytes and to generate a picture of their regulation at the transcriptional and posttranscriptional levels. Methods Human articular chondrocytes were cultured with resistin. Changes in gene expression were analyzed at various doses and times. Cells were also treated with the transcription inhibitor actinomycin D after resistin treatment or with the NF-,B inhibitor IKK-NBD before resistin treatment. Gene expression was tested by quantitative real-time polymerase chain reaction. Computational analysis for transcription factor binding motifs was performed on the promoter regions of differentially expressed genes. TC-28 chondrocytes were transfected with CCL3 and CCL4 promoter constructs, pNF-,B reporter, and NF-,B and CCAAT/enhancer binding protein , (C/EBP,) expression vectors with or without resistin. Results Resistin-treated human articular chondrocytes increased the expression of cytokines and chemokines. Levels of messenger RNA (mRNA) for matrix metalloproteinase 1 (MMP-1), MMP-13, and ADAMTS-4 also increased, while type II collagen ,1 (COL2A1) and aggrecan were down-regulated. The cytokine and chemokine genes could be categorized into 3 groups according to the pattern of mRNA expression over a 24-hour time course. One pattern suggested rapid regulation by mRNA stability. The second and third patterns were consistent with transcriptional regulation. Computational analysis suggested the transcription factors NF-,B and C/EBP, were involved in the resistin-induced up-regulation. This prediction was confirmed by the cotransfection of NF-,B and C/EBP, and the IKK-NBD inhibition. Conclusion Resistin has diverse effects on gene expression in human chondrocytes, affecting chemokines, cytokines, and matrix genes. Messenger RNA stabilization and transcriptional up-regulation are involved in resistin-induced gene expression in human chondrocytes. [source] Induction of CCL13 expression in synovial fibroblasts highlights a significant role of oncostatin M in rheumatoid arthritisARTHRITIS & RHEUMATISM, Issue 7 2009Christoph Hintzen Objective To investigate the molecular mechanisms of CCL13/monocyte chemoattractant protein 4 (MCP-4) chemokine expression through proinflammatory cytokines in different primary human fibroblasts and the contribution of CCL13 to monocyte migration. Methods Using RNase protection assays and enzyme-linked immunosorbent assays, we quantified the expression of CCL13 compared with that of CCL2/MCP-1 in primary human fibroblasts. Boyden chamber assays were performed to determine the importance of CCL13 for migration of primary monocytes. Pharmacologic inhibitors as well as small interfering RNA knockdown approaches were used to investigate the signaling pathways regulating CCL13 expression. Results The interleukin-6 (IL-6),type cytokine oncostatin M (OSM) was a powerful inducer of CCL13 expression in primary synovial fibroblasts from patients with rheumatoid arthritis (RA) as well as those from healthy control subjects but not in other types of fibroblasts. Neither IL-6 nor tumor necrosis factor , could stimulate the expression of CCL13 in synovial fibroblasts; IL-1, was a very weak inducer. Synovial fibroblasts from patients with RA constitutively produced low amounts of CCL13, which was partially dependent on constitutive production of OSM. By investigating the underlying molecular mechanism, we identified STAT-5, ERK-1/2, and p38 as critical factors involved in OSM-dependent transcription and messenger RNA stabilization of CCL13. Conclusion In contrast to other prominent cytokines involved in the pathogenesis of RA, OSM can strongly up-regulate the expression of CCL13, a chemokine recently identified in the synovial fluid of patients with RA. Despite potent OSM-induced signal transduction in all types of fibroblasts analyzed, only synovial fibroblasts secreted CCL13, which might be indicative of tissue-specific imprinting of different fibroblasts during development. [source] | ||||||||||