scholarly journals Regulation of Kv11.1 Isoform Expression by Polyadenylate Binding Protein Nuclear 1

2021 ◽  
Vol 22 (2) ◽  
pp. 863
Author(s):  
Matthew R. Stump ◽  
Rachel T. Nguyen ◽  
Rachel H. Drgastin ◽  
Delaney Search ◽  
Qiuming Gong ◽  
...  
Keyword(s):  
Rna Binding ◽  
Binding Protein ◽  
Alternative Polyadenylation ◽  
Luciferase Reporter ◽  
Delayed Rectifier ◽  
Rnase Protection ◽  
Relative Expression ◽  
Relative Expression Level ◽  
Reporter Assays ◽  
Isoform Expression

The Kv11.1 voltage-gated potassium channel, encoded by the KCNH2 gene, conducts the rapidly activating delayed rectifier current in the heart. KCNH2 pre-mRNA undergoes alternative polyadenylation to generate two C-terminal Kv11.1 isoforms in the heart. Utilization of a poly(A) signal in exon 15 produces the full-length, functional Kv11.1a isoform, while intron 9 polyadenylation generates the C-terminally truncated, nonfunctional Kv11.1a-USO isoform. The relative expression of Kv11.1a and Kv11.1a-USO isoforms plays an important role in the regulation of Kv11.1 channel function. In this study, we tested the hypothesis that the RNA polyadenylate binding protein nuclear 1 (PABPN1) interacts with a unique 22 nt adenosine stretch adjacent to the intron 9 poly(A) signal and regulates KCNH2 pre-mRNA alternative polyadenylation and the relative expression of Kv11.1a C-terminal isoforms. We showed that PABPN1 inhibited intron 9 poly(A) activity using luciferase reporter assays, tandem poly(A) reporter assays, and RNA pulldown assays. We also showed that PABPN1 increased the relative expression level of the functional Kv11.1a isoform using RNase protection assays, immunoblot analyses, and patch clamp recordings. Our present findings suggest a novel role for the RNA-binding protein PABPN1 in the regulation of functional and nonfunctional Kv11.1 isoform expression.

Abstract 174: Regulation of Kv11.1 C-terminal Isoform Expression by Polypyrimidine Tract Binding Protein

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Qiuming Gong ◽  
Anastasiya Goldys ◽  
Zhengfeng Zhou
Keyword(s):  
Rna Binding ◽  
Binding Protein ◽  
Developmental Regulation ◽  
Delayed Rectifier ◽  
Polypyrimidine Tract ◽  
Rnase Protection ◽  
Polypyrimidine Tract Binding ◽  
Alternative Processing ◽  
Polypyrimidine Tract Binding Protein ◽  
Isoform Expression

The KCNH2 gene encodes the Kv11.1 potassium channel that conducts the rapidly activating delayed rectifier current in the heart. KCNH2 pre-mRNA undergoes alternative processing. Intron 9 splicing leads to the formation of a functional, full-length Kv11.1a isoform, and polyadenylation within intron 9 generates a non-functional, C-terminally truncated Kv11.1a-USO isoform. In this study we investigated the developmental regulation of Kv11.1 isoform expression. We showed that Kv11.1a expression was lower than that of Kv11.1a-USO in the adult heart, but the levels of Kv11.1a and Kv11.1a-USO were similar in the fetal heart. We studied the effect of polypyrimidine tract binding protein (PTB) on the alternative processing of KCNH2 pre-mRNA. PTB is an RNA-binding protein well known for its role in the regulation of alternative splicing. Recently, PTB has been shown to regulate polyadenylation. We showed that PTB increased Kv11.1a isoform expression and decreased Kv11.1a-USO isoform expression by the RNase protection assay and immunoblot analysis. In patch-clamp experiments, we found that PTB significantly increased Kv11.1 current. Our findings suggest that the relative expression of Kv11.1 C-terminal isoforms can be regulated by PTB. It has been reported that PTB protein abundance is progressively reduced during postnatal heart development. Thus, PTB may play an important role in developmental regulation of Kv11.1 isoform expression in the heart.

The KH-type splicing regulatory protein (KSRP) regulates type III interferon expression post-transcriptionally

2019 ◽  
Vol 476 (2) ◽  
pp. 333-352 ◽  
Author(s):  
Lisa Schmidtke ◽  
Katharina Schrick ◽  
Sabrina Saurin ◽  
Rudolf Käfer ◽  
Fabian Gather ◽  
...  
Keyword(s):  
Half Life ◽  
Rna Binding ◽  
Binding Protein ◽  
Regulatory Protein ◽  
Rna Binding Protein ◽  
Luciferase Reporter ◽  
Regulatory Function ◽  
Type Iii ◽  
Type Iii Ifn ◽  
Mrna Half Life

Abstract Type III interferons (IFNs) are the latest members of the IFN family. They play an important role in immune defense mechanisms, especially in antiviral responses at mucosal sites. Moreover, they control inflammatory reactions by modulating neutrophil and dendritic cell functions. Therefore, it is important to identify cellular mechanisms involved in the control of type III IFN expression. All IFN family members contain AU-rich elements (AREs) in the 3′-untranslated regions (3′-UTR) of their mRNAs that determine mRNA half-life and consequently the expressional level of these cytokines. mRNA stability is controlled by different proteins binding to these AREs leading to either stabilization or destabilization of the respective target mRNA. The KH-type splicing regulatory protein KSRP (also named KHSRP) is an important negative regulator of ARE-containing mRNAs. Here, we identify the interferon lambda 3 (IFNL3) mRNA as a new KSRP target by pull-down and immunoprecipitation experiments, as well as luciferase reporter gene assays. We characterize the KSRP-binding site in the IFNL3 3′-UTR and demonstrate that KSRP regulates the mRNA half-life of the IFNL3 transcript. In addition, we detect enhanced expression of IFNL3 mRNA in KSRP−/− mice, establishing a negative regulatory function of KSRP in type III IFN expression also in vivo. Besides KSRP the RNA-binding protein AUF1 (AU-rich element RNA-binding protein 1) also seems to be involved in the regulation of type III IFN mRNA expression.

scholarly journals EWSR1-induced circNEIL3 promotes glioma progression and exosome-mediated macrophage immunosuppressive polarization via stabilizing IGF2BP3

2022 ◽  
Vol 21 (1) ◽  
Author(s):  
Ziwen Pan ◽  
Rongrong Zhao ◽  
Boyan Li ◽  
Yanhua Qi ◽  
Wei Qiu ◽  
...  
Keyword(s):  
Rna Binding ◽  
Binding Protein ◽  
Expression Profiles ◽  
Tumour Microenvironment ◽  
Malignant Progression ◽  
Luciferase Reporter ◽  
Sequencing Analysis ◽  
Glioma Progression

Abstract Background Gliomas are the most common malignant primary brain tumours with a highly immunosuppressive tumour microenvironment (TME) and poor prognosis. Circular RNAs (circRNA), a newly found type of endogenous noncoding RNA, characterized by high stability, abundance, conservation, have been shown to play an important role in the pathophysiological processes and TME remodelling of various tumours. Methods CircRNA sequencing analysis was performed to explore circRNA expression profiles in normal and glioma tissues. The biological function of a novel circRNA, namely, circNEIL3, in glioma development was confirmed both in vitro and in vivo. Mechanistically, RNA pull-down, mass spectrum, RNA immunoprecipitation (RIP), luciferase reporter, and co-immunoprecipitation assays were conducted. Results We identified circNEIL3, which could be cyclized by EWS RNA-binding protein 1(EWSR1), to be upregulated in glioma tissues and to correlate positively with glioma malignant progression. Functionally, we confirmed that circNEIL3 promotes tumorigenesis and carcinogenic progression of glioma in vitro and in vivo. Mechanistically, circNEIL3 stabilizes IGF2BP3 (insulin-like growth factor 2 mRNA binding protein 3) protein, a known oncogenic protein, by preventing HECTD4-mediated ubiquitination. Moreover, circNEIL3 overexpression glioma cells drives macrophage infiltration into the tumour microenvironment (TME). Finally, circNEIL3 is packaged into exosomes by hnRNPA2B1 and transmitted to infiltrated tumour associated macrophages (TAMs), enabling them to acquire immunosuppressive properties by stabilizing IGF2BP3 and in turn promoting glioma progression. Conclusions This work reveals that circNEIL3 plays a nonnegligible multifaceted role in promoting gliomagenesis, malignant progression and macrophage tumour-promoting phenotypes polarization, highlighting that circNEIL3 is a potential prognostic biomarker and therapeutic target in glioma.

scholarly journals Regulation of thrombospondin-1 expression through AU-rich elements in the 3′UTR of the mRNA

2011 ◽  
Vol 16 (1) ◽  
Author(s):  
Asa Mcgray ◽  
Timothy Gingerich ◽  
James Petrik ◽  
Jonathan Lamarre
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Half Life ◽  
Rna Binding ◽  
Binding Protein ◽  
Site Directed Mutagenesis ◽  
Hek293 Cells ◽  
Luciferase Reporter ◽  
Thrombospondin 1 ◽  
Mrna Half Life

AbstractThrombospondin-1 (TSP-1) is a matricellular protein that participates in numerous normal and pathological tissue processes and is rapidly modulated by different stimuli. The presence of 8 highly-conserved AU rich elements (AREs) within the 3′-untranslated region (3′UTR) of the TSP-1 mRNA suggests that post-transcriptional regulation is likely to represent one mechanism by which TSP-1 gene expression is regulated. We investigated the roles of these AREs, and proteins which bind to them, in the control of TSP-1 mRNA stability. The endogenous TSP-1 mRNA half-life is approximately 2.0 hours in HEK293 cells. Luciferase reporter mRNAs containing the TSP-1 3′UTR show a similar rate of decay, suggesting that the 3′UTR influences the decay rate. Site-directed mutagenesis of individual and adjacent AREs prolonged reporter mRNA halflife to between 2.2 and 4.4 hours. Mutation of all AREs increased mRNA half life to 8.8 hours, suggesting that all AREs have some effect, but that specific AREs may have key roles in stability regulation. A labeled RNA oligonucleotide derived from the most influential ARE was utilized to purify TSP-1 AREbinding proteins. The AU-binding protein AUF1 was shown to associate with this motif. These studies reveal that AREs in the 3′UTR control TSP-1 mRNA stability and that the RNA binding protein AUF1 participates in this control. These studies suggest that ARE-dependent control of TSP-1 mRNA stability may represent an important component in the control of TSP-1 gene expression.

scholarly journals Long noncoding RNA HOTAIR mediates the estrogen-induced metastasis of endometrial cancer cells via the miR-646/NPM1 axis

2018 ◽  
Vol 314 (6) ◽  
pp. C690-C701 ◽  
Author(s):  
Yun-xiao Zhou ◽  
Chuan Wang ◽  
Li-wei Mao ◽  
Yan-li Wang ◽  
Li-qun Xia ◽  
...  
Keyword(s):  
Noncoding Rna ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Protein ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Qrt Pcr ◽  
Reporter Assays ◽  
Ec Cells

LncRNA homeobox (HOX) transcript antisense intergenic RNA (HOTAIR) has been confirmed to be involved in the tumorigenic progression of endometrial carcinoma (EC). However, the molecular mechanisms of HOTAIR in EC are not fully elucidated. The expression of HOTAIR and miR-646 in human EC tissues was determined by qRT-PCR. The effect of miR-646 on EC cells was assessed by the cell viability, migration, and invasion using CCK-8 assays and transwell assays. RNA-binding protein immunoprecipitation assays and RNA pull-down assays were performed to explore the interaction between HOTAIR and miR-646. The regulation of miR-646 on nucleophosmin 1 (NPM1) was tested using luciferase reporter assays. MiR-646 expression was significantly decreased both in human EC tissues ( n = 23) and cell lines (Ishikawa and HEC-1-A) compared with the control. Moreover, miR-646 expression was negatively related to HOTAIR in human EC tissues ( n = 23). Our results also showed that miR-646 overexpression considerably attenuated the E2-promoted viability, migration, and invasion of Ishikawa and HEC-1-A cells in vitro. In addition, HOTAIR was confirmed to regulate the viability, migration, and invasion of EC cells through negative regulating miR-646. More importantly, we also demonstrated that NPM1 was the target of miR-646, and HOTAIR promoted NPM1 expression through interacting with miR-646 in EC cells. Taken together, our findings presented that HOTAIR could regulate NPM1 via interacting with miR-646, thereby governing the viability, migration, and invasion of EC cells.

RNA-binding protein CELF1 enhances cell migration, invasion, and chemoresistance by targeting ETS2 in colorectal cancer

2020 ◽  
Vol 134 (14) ◽  
pp. 1973-1990
Author(s):  
Huaiming Wang ◽  
Rongkang Huang ◽  
Wentai Guo ◽  
Xiusen Qin ◽  
Zifeng Yang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Rna Binding ◽  
Malignant Tumors ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Tumor Growth Model

Abstract Colorectal cancer (CRC) is often diagnosed at later stages after it has metastasized to other organs. The development of chemoresistance also contributes to a poor prognosis. Therefore, an increased understanding of the metastatic properties of CRC and chemoresistance could improve patient survival. CUGBP elav-like family member 1 (CELF1) is an RNA-binding protein, which is overexpressed in many human malignant tumors. However, the influence of CELF1 in CRC is unclear. V-ets erythroblastosis virus E26 oncogene homologue 2 (ETS2) is an evolutionarily conserved proto-oncogene known to be overexpressed in a variety of human cancers including CRC. In thespresent tudy, we investigated the association between CELF1 and ETS2 in CRC tumorigenesis and oxaliplatin (L-OHP) resistance. We found a positive correlation between the elevated expression of CELF1 and ETS2 in human CRC tissues. Overexpression of CELF1 increased CRC cell proliferation, migration, and invasion in vitro and in a xenograft tumor growth model in vivo, and induced resistance to L-OHP. In contrast, CELF1 knockdown improved the response of CRC cells to L-OHP. Overexpression of ETS2 increased the malignant behavior of CRC cells (growth, migration, and invasion) and L-OHP resistance in vitro. Moreover, L-OHP resistance induced by CELF1 overexpression was reversed by ETS2 knockdown. The results of luciferase reporter and ribonucleoprotein immunoprecipitation assays indicated that CELF1 up-regulates ETS2 by binding to its 3′-UTR. Taken together, our findings have identified that CELF1 regulates ETS2 in a mechanism that results in CRC tumorigenesis and L-OHP resistance, and CELF1 may be a promising target for overcoming chemoresistance in CRC.

scholarly journals The RNA-binding protein QKI5 is a direct target of C/EBPα and delays macrophage differentiation

2012 ◽  
Vol 23 (9) ◽  
pp. 1628-1635 ◽  
Author(s):  
Haiyan Fu ◽  
Guodong Yang ◽  
Mengying Wei ◽  
Li Liu ◽  
Liang Jin ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Macrophage Differentiation ◽  
Endogenous Expression ◽  
Enhancer Binding Protein ◽  
Reporter Assays ◽  
Direct Target ◽  
Site Blocking

Differentiated macrophages are essential for the innate immune system; however, the molecular mechanisms underlying the generation of macrophages remain largely unknown. Here we show that the RNA-binding protein QKI, mainly QKI-5, is transcriptionally activated in the early differentiated monocytic progenitors when CCAAT/enhancer-binding protein (C/EBP) α is expressed. The forced expression of C/EBPα increases the endogenous expression of QKI. Chromatin immunoprecipitation analysis and reporter assays further confirm that C/EBPα activates the transcription of QKI, primarily by binding to the distal C/EBPα-binding site. Blocking the induction of QKI using RNA interference enhances the expression of endogenous CSF1R and facilitates macrophage differentiation. Further study of the mechanism reveals that QKI-5 facilitates the degradation of CSF1R mRNA by interacting with the distal QRE in the 3′ untranslated region. In summary, we show that in committed macrophage progenitors, C/EBPα-activated QKI-5 negatively regulates macrophage differentiation by down-regulating CSF1R expression, forming a negative feedback loop during macrophage differentiation.

A novel p53 target gene, S100A9, induces p53-dependent cellular apoptosis and mediates the p53 apoptosis pathway

2009 ◽  
Vol 422 (2) ◽  
pp. 363-372 ◽  
Author(s):  
Chunsun Li ◽  
Hongyan Chen ◽  
Fang Ding ◽  
Yu Zhang ◽  
Aiping Luo ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Luciferase Reporter ◽  
Dependent Manner ◽  
Apoptosis Pathway ◽  
Cellular Apoptosis ◽  
Reporter Assays ◽  
P53 Activation ◽  
Acute And Chronic Inflammation

S100A9 (S100 calcium-binding protein A9) is a calcium-binding protein of the S100 family, and its differential expression has been associated with acute and chronic inflammation and several human cancers. Our previous work showed that S100A9 was severely down-regulated in human ESCC (oesophageal squamous cell carcinoma). To further investigate the transcriptional regulation of S100A9, we analysed the S100A9 promoter region and found several putative p53BS (p53-binding sites). Luciferase reporter assays showed that constructs carrying the p53BS exhibited enhanced luciferase activity in response to wild-type p53 activation. Further study demonstrated that S100A9 mRNA and protein expression could be positively regulated in a p53-dependent manner and p53 could bind to p53BS on the S100A9 promoter. Overexpression of S100A9 could induce cellular apoptosis, and this was partly p53-dependent. Knockdown of S100A9 impaired the apoptosis induced by p53. Thus we conclude that a gene down-regulated in ESCC, S100A9, is a novel p53 transcriptional target, induces cellular apoptosis in a partly p53-dependent manner and mediates the p53 apoptosis pathway.

Promoter I of the ovine acetyl-CoA carboxylase-α gene: an E-box motif at −114 in the proximal promoter binds upstream stimulatory factor (USF)-1 and USF-2 and acts as an insulin-response sequence in differentiating adipocytes

2001 ◽  
Vol 359 (2) ◽  
pp. 273-284 ◽  
Author(s):  
Maureen T. TRAVERS ◽  
Amanda J. VALLANCE ◽  
Helen T. GOURLAY ◽  
Clare A. GILL ◽  
Izabella KLEIN ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Binding Protein ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Acetyl Coa Carboxylase ◽  
Upstream Stimulatory Factor ◽  
Acetyl Coa ◽  
Rnase Protection ◽  
E Box ◽  
Stimulatory Factor

Acetyl-CoA carboxylase-α (ACC-α) plays a central role in co-ordinating de novo fatty acid synthesis in animal tissues. We have characterized the regulatory region of the ovine ACC-α gene. Three promoters, PI, PII and PIII, are dispersed throughout 50kb of genomic DNA. Expression from PI is limited to adipose tissue and liver. Sequence comparison of the proximal promoters of ovine and mouse PIs demonstrates high nucleotide identity and that they are characterized by a TATA box at −29, C/EBP (CCAAT enhancer-binding protein)-binding motifs and multiple E-box motifs. A 4.3kb ovine PI-luciferase reporter construct is insulin-responsive when transfected into differentiated ovine adipocytes, whereas when this construct is transfected into ovine preadipocytes and HepG2 cells the construct is inactive and is not inducible by insulin. By contrast, transfection of a construct corresponding to 132bp of the proximal promoter linked to a luciferase reporter is active and inducible by insulin in all three cell systems. Insulin signalling to the −132bp construct in differentiated ovine adipocytes involves, in part, an E-box motif at −114. Upstream stimulatory factor (USF)-1 and USF-2, but not sterol regulatory element-binding protein 1 (SREBP-1), are major components of protein complexes that bind this E-box motif. Activation of the 4.3kb PI construct in differentiated ovine adipocytes is associated with endogenous expression of PI transcripts throughout differentiation; PI transcripts are not detectable by RNase-protection assay in ovine preadipocytes, HepG2 cells or 3T3-F442A adipocytes. These data indicate the presence of repressor motifs in PI that are required to be de-repressed during adipocyte differentiation to allow induction of the promoter by insulin.

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