scholarly journals Minor introns are embedded molecular switches regulated by highly unstable U6atac snRNA

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Ihab Younis ◽  
Kimberly Dittmar ◽  
Wei Wang ◽  
Shawn W Foley ◽  
Michael G Berg ◽  
...  

Eukaryotes have two types of spliceosomes, comprised of either major (U1, U2, U4, U5, U6) or minor (U11, U12, U4atac, U6atac; <1%) snRNPs. The high conservation of minor introns, typically one amidst many major introns in several hundred genes, despite their poor splicing, has been a long-standing enigma. Here, we discovered that the low abundance minor spliceosome’s catalytic snRNP, U6atac, is strikingly unstable (t½<2 hr). We show that U6atac level depends on both RNA polymerases II and III and can be rapidly increased by cell stress-activated kinase p38MAPK, which stabilizes it, enhancing mRNA expression of hundreds of minor intron-containing genes that are otherwise suppressed by limiting U6atac. Furthermore, p38MAPK-dependent U6atac modulation can control minor intron-containing tumor suppressor PTEN expression and cytokine production. We propose that minor introns are embedded molecular switches regulated by U6atac abundance, providing a novel post-transcriptional gene expression mechanism and a rationale for the minor spliceosome’s evolutionary conservation.

1996 ◽  
Vol 271 (4) ◽  
pp. C1073-C1078 ◽  
Author(s):  
J. Stankova ◽  
P. D'Orleans-Juste ◽  
M. Rola-Pleszczynski

Endothelins are a family of potent vasoactive peptides that have also been implicated in inflammation. To examine the consequence of endothelin stimulation on cytokine production, we explored the effect of endothelin-1 (ET-1) on interleukin-6 (IL-6) gene expression. ET-1 augmented the production of IL-6 in human umbilical vein endothelial cells (HUVEC) by 2- to 5-fold and synergized with IL-1 to induce a 150-fold increase in IL-6 secretion, compared with spontaneous production. The peak of IL-6 production was in the presence of 100 pM ET-1 after 12 h of stimulation. ET-1 augmented IL-6 mRNA expression at the optimal concentration of 100 pM, in the presence of 1 ng/ml of IL-1. ET-1-induced IL-6 mRNA expression was significant within 4 h of stimulation and persisted for 18 h. Similarly, the ETB receptor-specific agonist, IRL-1620, also augmented IL-6 mRNA expression and IL-6 protein production in HUVEC. Our results suggest that endothelin may play a role at the vascular inflammatory site by modulating cytokine production through ETB receptor activation in endothelial cells of human origin.


2020 ◽  
Vol 20 (18) ◽  
pp. 2274-2284
Author(s):  
Faroogh Marofi ◽  
Jalal Choupani ◽  
Saeed Solali ◽  
Ghasem Vahedi ◽  
Ali Hassanzadeh ◽  
...  

Objective: Zoledronic Acid (ZA) is one of the common treatment choices used in various boneassociated conditions. Also, many studies have investigated the effect of ZA on Osteoblastic-Differentiation (OSD) of Mesenchymal Stem Cells (MSCs), but its clear molecular mechanism(s) has remained to be understood. It seems that the methylation of the promoter region of key genes might be an important factor involved in the regulation of genes responsible for OSD. The present study aimed to evaluate the changes in the mRNA expression and promoter methylation of central Transcription Factors (TFs) during OSD of MSCs under treatment with ZA. Materials and Methods: MSCs were induced to be differentiated into the osteoblastic cell lineage using routine protocols. MSCs received ZA during OSD and then the methylation and mRNA expression levels of target genes were measured by Methylation Specific-quantitative Polymerase Chain Reaction (MS-qPCR) and real.time PCR, respectively. The osteoblastic differentiation was confirmed by Alizarin Red Staining and the related markers to this stage. Results: Gene expression and promoter methylation level for DLX3, FRA1, ATF4, MSX2, C/EBPζ, and C/EBPa were up or down-regulated in both ZA-treated and untreated cells during the osteodifferentiation process on days 0 to 21. ATF4, DLX3, and FRA1 genes were significantly up-regulated during the OSD processes, while the result for MSX2, C/EBPζ, and C/EBPa was reverse. On the other hand, ATF4 and DLX3 methylation levels gradually reduced in both ZA-treated and untreated cells during the osteodifferentiation process on days 0 to 21, while the pattern was increasing for MSX2 and C/EBPa. The methylation pattern of C/EBPζ was upward in untreated groups while it had a downward pattern in ZA-treated groups at the same scheduled time. The result for FRA1 was not significant in both groups at the same scheduled time (days 0-21). Conclusion: The results indicated that promoter-hypomethylation of ATF4, DLX3, and FRA1 genes might be one of the mechanism(s) controlling their gene expression. Moreover, we found that promoter-hypermethylation led to the down-regulation of MSX2, C/EBP-ζ and C/EBP-α. The results implicate that ATF4, DLX3 and FRA1 may act as inducers of OSD while MSX2, C/EBP-ζ and C/EBP-α could act as the inhibitor ones. We also determined that promoter-methylation is an important process in the regulation of OSD. However, yet there was no significant difference in the promoter-methylation level of selected TFs in ZA-treated and control cells, a methylation- independent pathway might be involved in the regulation of target genes during OSD of MSCs.


2019 ◽  
Vol 13 (2) ◽  
pp. 140-148
Author(s):  
Mai Nasser ◽  
Noha M. Hazem ◽  
Amany Atwa ◽  
Amina Baiomy

Background: Rheumatoid Arthritis (RA) is an autoimmune, chronic, and systematic disease. It affects joints and bones. The exact etiology of RA is still unclear. Varied genetic and environmental factors have been associated with the increased risk for RA. Overactivation of Toll-Like Receptors (TLRs) could initiate the development of autoimmune diseases including RA. Objective: The aim of the study was to evaluate TLR2 gene expression in rheumatoid arthritis patients and investigate its correlation with the disease activity. Materials and Methods: This study included 60 patients and 20 healthy individuals. The patients were diagnosed with RA according to the 2010 American College of Rheumatology/ European League Against Rheumatism criteria (ACR/EULAR). All included subjects did not have any joint disorders and /or autoimmune diseases. RA disease activity was determined by the disease activity score of 28 joints. Whole blood was collected from all participants. Total RNA extraction was done. TLR2 mRNA expression was assessed by reverse transcription-PCR (RT-PCR). Results: TLR2 mRNA expression was found to be significantly higher in RA patients compared to healthy controls. Also, a strong positive correlation was found between TLR2 expression level and the disease activity score. A non significant positive correlation was found between TLR2 expression and serum Rheumatoid Factor (RF) level. Conclusion: TLR2 pathway may have an important role in RA pathogenesis and could be a new biomarker for diagnosis and monitoring disease activity.


1998 ◽  
Vol 83 (7) ◽  
pp. 2597-2600 ◽  
Author(s):  
M. Reincke ◽  
F. Beuschlein ◽  
E. Lalli ◽  
W. Arlt ◽  
S. Vay ◽  
...  

The DAX-1 gene encodes an orphan nuclear hormone receptor essential for normal fetal development of the adrenal cortex. Recently, DAX-1 has been shown to act as a transcriptional repressor of steroidogenic acute regulatory protein gene expression (StAR), suppressing steroidogenesis. We, therefore, investigated the expression of DAX-1 in a variety of adrenocortical tumors and compared the results with StAR mRNA expression. We found low or absent DAX-1 expression in aldosterone-producing adenomas (n=11: 35±11%; normal adrenals: 100±17%) and in aldosterone-producing adrenocortical carcinomas (n=2: 24 and 36%). Cortisol-producing adenomas showed intermediate DAX-1 expression (n=8; 92±16), as did 3 non-aldosterone-producing carcinomas (72, 132 and 132%). High DAX-1 expression was present in nonfunctional adenomas (n=3; 160±17%). In contrast to DAX-1, StAR mRNA expression did not show significant variations between groups. We did not detect the expected negative correlation between DAX-1 and StAR mRNA in adrenocortical tumors. These data suggest that high DAX-1 expression in adrenocortical tumors is associated with a non-functional phenotype whereas low DAX-1 expression favors mineralo-corticoid secretion. These effects on steroidogenesis are mediated by mechanisms other than repression of StAR gene expression. Our results indicate that DAX-1 may be one of the factors influencing the steroid biosynthesis of adrenocortical neoplasms.


2006 ◽  
Vol 82 (6) ◽  
pp. 877-887 ◽  
Author(s):  
J. Sehm ◽  
H. Lindermayer ◽  
H. H. D. Meyer ◽  
M. W. Pfaffl

Flavan-3-ols are a class of flavonoids that are widely distributed in fruits and beverages including red wine and apples. Consumption of flavanoid-rich food has been shown to exhibit anti-microbial, anti-oxidative, anti-inflammatory, and immune-modulating effects. To test the nutritional effects of flavanols on mRNA gene-expression of inflammatory and apoptotic marker genes, piglets were given two flavanoids-rich feeding regimens: a low flavanoid standard diet (SD) was compared with diets enriched with 3·5% apple pomace (APD) or 3·5% red-wine pomace (RWPD). The influence on mRNA expression levels was investigated in different immunological active tissues and in the gastro-intestinal tract (GIT). The investigation took place from 1 week prior weaning to 19 days post weaning in 78 piglets. The expression of expressed marker genes was determinate by one-step quantitative real-time (qRT-PCR): TNFα, NFκB as pro-inflammatory; IL10, as anti-inflammatory; caspase 3 as apoptosis; cyclin D1 as cell cycle marker; and nucleosome component histon H3 as reference gene.The feeding regimens result in tissue individual regulation of mRNA gene expression in all investigated organs. It was discovered that there were significant differences between the applied diets and significant changes during feeding time curse. Both pomace treatments caused a significant up-regulation of all investigated genes in liver. The effect on mesenterial lymph nodes and spleen was not prominent. In the GIT, the treatment groups showed a inhibitory effects on gene expression mainly in stomach and jejunum (NFκB, cyclin D1 and caspase 3). In colon the trend of caspase 3 was positive with the greatest change in the RWPD group.In jejunum and stomach the cell cycle turn over was reduced, whereas in liver the cell turn over was highly accelerate. The influence on inflammatory marker gene expression is mainly relevant in stomach. It is presume that both flavanoid rich feeding regimens have the potential to modulate the mRNA expressions of inflammatory, proliferation and apoptotic marker genes in the GIT and piglet organs.


2008 ◽  
Vol 32 (2) ◽  
pp. 219-228 ◽  
Author(s):  
Adeel Safdar ◽  
Nicholas J. Yardley ◽  
Rodney Snow ◽  
Simon Melov ◽  
Mark A. Tarnopolsky

Creatine monohydrate (CrM) supplementation has been shown to increase fat-free mass and muscle power output possibly via cell swelling. Little is known about the cellular response to CrM. We investigated the effect of short-term CrM supplementation on global and targeted mRNA expression and protein content in human skeletal muscle. In a randomized, placebo-controlled, crossover, double-blind design, 12 young, healthy, nonobese men were supplemented with either a placebo (PL) or CrM (loading phase, 20 g/day × 3 days; maintenance phase, 5 g/day × 7 days) for 10 days. Following a 28-day washout period, subjects were put on the alternate supplementation for 10 days. Muscle biopsies of the vastus lateralis were obtained and were assessed for mRNA expression (cDNA microarrays + real-time PCR) and protein content (Kinetworks KPKS 1.0 Protein Kinase screen). CrM supplementation significantly increased fat-free mass, total body water, and body weight of the participants ( P < 0.05). Also, CrM supplementation significantly upregulated (1.3- to 5.0-fold) the mRNA content of genes and protein content of kinases involved in osmosensing and signal transduction, cytoskeleton remodeling, protein and glycogen synthesis regulation, satellite cell proliferation and differentiation, DNA replication and repair, RNA transcription control, and cell survival. We are the first to report this large-scale gene expression in the skeletal muscle with short-term CrM supplementation, a response that suggests changes in cellular osmolarity.


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