Control of Na+-K+-ATPase β1-subunit expression: role of 3′-untranslated region

2004 ◽  
Vol 286 (3) ◽  
pp. C580-C585 ◽  
Author(s):  
Yvonne Shao ◽  
Faramarz Ismail-Beigi
Keyword(s):  
Untranslated Region ◽  
Ventricular Myocardium ◽  
Distal Segment ◽  
In Vitro Translation ◽  
Luciferase Expression ◽  
Translational Efficiency ◽  
Stem Loop ◽  
Subunit Expression

Using in vitro translation and cell transfection assays, we previously demonstrated that the Na+-K+-ATPase β1 mRNA species containing its longest 3′-untranslated region (UTR) exhibited the lowest translational efficiency. Here, employing deletions and in vivo expression assays, using direct injection of plasmids into rat ventricular myocardium, we identified a 143-nt segment located in the distal 3′-UTR of β1 mRNA that was associated with decreased luciferase expression; interestingly, this segment contains three AUUUA motifs. Using RNA-protein binding assays and UV cross-linking of cRNA with cytosolic proteins of rat heart, we identified an ∼38-kDa protein that specifically bound to the cRNA encoding the 143-nt segment of β1 mRNA 3′-UTR. Mutation of three nucleotides located in the middle region of the 143-nt segment, which was predicted to greatly disrupt a putative stem-loop structure of the cRNA in this region, was associated with reduced binding of the mutated cRNA to the protein migrating at ∼38 kDa. The cRNA encoding a segment of cyclooxygenase-2 mRNA 3′-UTR containing six AUUUA sequences did not bind the protein migrating at ∼38 kDa and did not compete with the binding of the wild-type 143-nt β1 cRNA to the protein. The above results suggest that the 143-nt segment in the distal segment of the 3′-UTR of β1 mRNA may play an important role in the control of β1-subunit expression.

scholarly journals A Novel Assay for Viral MicroRNA Function Identifies a Single Nucleotide Polymorphism That Affects Drosha Processing

2006 ◽  
Vol 80 (11) ◽  
pp. 5321-5326 ◽  
Author(s):  
Eva Gottwein ◽  
Xuezhong Cai ◽  
Bryan R. Cullen
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Target Genes ◽  
Human Herpesvirus ◽  
Northern Analysis ◽  
Luciferase Expression ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Stem Loop

ABSTRACT MicroRNAs (miRNAs) are a class of ∼22-nucleotide noncoding RNAs that inhibit the expression of specific target genes at the posttranscriptional level. Recently, 11 miRNAs encoded by the pathogenic human herpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV) were cloned from latently infected cells. While the expression of these miRNAs has been confirmed by Northern analysis, their ability to inhibit target gene expression has not been demonstrated. We have devised a novel assay for miRNA function that uses lentiviral indicator vectors carrying two perfectly complementary target sites for each given miRNA in the 3′ untranslated region of the Renilla luciferase gene. This assay allowed us to demonstrate the activity of each viral miRNA upon cotransduction of cells with the Renilla luciferase indicator vector together with a firefly luciferase control vector. In KSHV-infected BC-1 and BCBL-1 cells, but not uninfected control cells, Renilla luciferase expression was selectively reduced up to 10-fold. Interestingly, one of the viral miRNAs (miR-K5) exhibited much higher activity in BC-1 cells than in BCBL-1 cells. Sequence analysis of both viral genomes revealed a single nucleotide polymorphism in the miR-K5 precursor stem-loop, which inhibits the expression of mature miR-K5 in BCBL-1 cells. We show that the primary miR-K5 sequence present in BCBL-1 results in diminished processing by Drosha both in vivo and in vitro. This is the first report of a naturally occurring sequence polymorphism in an miRNA precursor that results in reduced processing and therefore lower levels of mature miRNA expression and function.

scholarly journals Control of the translational efficiency of beta-F1-ATPase mRNA depends on the regulation of a protein that binds the 3' untranslated region of the mRNA.

1997 ◽  
Vol 17 (9) ◽  
pp. 5255-5268 ◽  
Author(s):  
J M Izquierdo ◽  
J M Cuezva
Keyword(s):  
Untranslated Region ◽  
Fetal Liver ◽  
Mrna Translation ◽  
Full Length ◽  
In Vitro Translation ◽  
Translational Efficiency ◽  
Reporter Construct ◽  
F1 Atpase ◽  
Atpase Gene

The expression of the nucleus-encoded beta-F1-ATPase gene of oxidative phosphorylation is developmentally regulated in the liver at both the transcriptional and posttranscriptional levels. In this study we have analyzed the potential mechanisms that control the cytoplasmic expression of beta-F1-ATPase mRNA during liver development. Remarkably, a full-length 3' untranslated region (UTR) of the transcript is required for its efficient in vitro translation. When the 3' UTR of beta-F1-ATPase mRNA is placed downstream of a reporter construct, it functions as a translational enhancer. In vitro translation experiments with full-length beta-F1-ATPase mRNA and with a chimeric reporter construct containing the 3' UTR of beta-F1-ATPase mRNA suggested the existence of an inhibitor of beta-F1-ATPase mRNA translation in the fetal liver. Electrophoretic mobility shift assays and UV cross-linking experiments allowed the identification of an acutely regulated protein (3'betaFBP) of the liver that binds at the 3' UTR of beta-F1-ATPase mRNA. The developmental profile of 3'betaFBP parallels the reported changes in the translational efficiency of beta-F1-ATPase mRNA during development. Fractionation of fetal liver extracts revealed that the inhibitory activity of beta-F1-ATPase mRNA translation cofractionates with 3'-UTR band-shifting activity. Compared to other tissues of the adult rat, kidney and spleen extracts showed very high expression levels of 3'betaFBP. Translation of beta-F1-ATPase mRNA in the presence of kidney and spleen extracts further supported a translational inhibitory role for 3'betaFBP. Mapping experiments and a deletion mutant of the 3' UTR revealed that the cis-acting element for binding 3'betaFBP is located within a highly conserved region of the 3' UTR of mammalian beta-F1-ATPase mRNAs. Overall, we have identified a mechanism of translational control that regulates the rapid postnatal differentiation of liver mitochondria.

scholarly journals Small cis-Acting Sequences That Specify Secondary Structures in a Chloroplast mRNA Are Essential for RNA Stability and Translation

1999 ◽  
Vol 19 (12) ◽  
pp. 8479-8491 ◽  
Author(s):  
David C. Higgs ◽  
Risa S. Shapiro ◽  
Karen L. Kindle ◽  
David B. Stern
Keyword(s):  
Untranslated Region ◽  
Rna Stability ◽  
Dimethyl Sulfate ◽  
Secondary Structures ◽  
Rna Modification ◽  
Range Interaction ◽  
Stem Loop ◽  
Chloroplast Mrna

ABSTRACT Nucleus-encoded proteins interact with cis-acting elements in chloroplast transcripts to promote RNA stability and translation. We have analyzed the structure and function of three such elements within the Chlamydomonas petD 5′ untranslated region; petD encodes subunit IV of the cytochromeb 6/f complex. These elements were delineated by linker-scanning mutagenesis, and RNA secondary structures were investigated by mapping nuclease-sensitive sites in vitro and by in vivo dimethyl sulfate RNA modification. Element I spans a maximum of 8 nucleotides (nt) at the 5′ end of the mRNA; it is essential for RNA stability and plays a role in translation. This element appears to form a small stem-loop that may interact with a previously described nucleus-encoded factor to block 5′→3′ exoribonucleolytic degradation. Elements II and III, located in the center and near the 3′ end of the 5′ untranslated region, respectively, are essential for translation, but mutations in these elements do not affect mRNA stability. Element II is a maximum of 16 nt in length, does not form an obvious secondary structure, and appears to bind proteins that protect it from dimethyl sulfate modification. Element III spans a maximum of 14 nt and appears to form a stem-loop in vivo, based on dimethyl sulfate modification and the sequences of intragenic suppressors of element III mutations. Furthermore, mutations in element II result in changes in the RNA structure near element III, consistent with a long-range interaction that may promote translation.

scholarly journals In vitro and in vivo identification of structural and sequence elements in the 5′ untranslated region of Ectropis obliqua picorna-like virus required for internal initiation

2006 ◽  
Vol 87 (12) ◽  
pp. 3667-3677 ◽  
Author(s):  
Jie Lu ◽  
Jiamin Zhang ◽  
Xiaochun Wang ◽  
Hong Jiang ◽  
Chuanfeng Liu ◽  
...  
Keyword(s):  
Untranslated Region ◽  
Site Directed Mutagenesis ◽  
Polypyrimidine Tract ◽  
Entry Site ◽  
Stem Loop ◽  
Internal Ribosome Entry ◽  
Sequence Elements ◽  
Internal Initiation

Ectropis obliqua picorna-like virus (EoPV) is a newly described insect virus that is classified as a putative member of the genus Iflavirus. The virus possesses a large, positive-sense RNA genome encoding a single polyprotein that shares physicochemical properties with those of members of the family Picornaviridae. The 5′ untranslated region (5′ UTR) plays an important role in picornavirus translation initiation, as it contains an internal ribosome entry site (IRES) that mediates cap-independent translation. To investigate translation in EoPV, an extensive range of mutations were engineered within the 5′ UTR and the effects of these changes were examined in vitro and in vivo by using a bicistronic construct. Results showed that deletions within the first 63 nt had little impact on IRES activity, whilst core IRES function was contained within stem–loops C and D, as their removal abrogated IRES activity significantly. In contrast to these findings, removal of stem–loop G containing two cryptic AUGs caused a remarkable increase in IRES activity, which was further investigated by site-directed mutagenesis at these two positions. It was also confirmed that initiation of protein synthesis occurs at AUG6 (position 391–394) and not at the AUG immediately downstream of the polypyrimidine tract. Mutation of the polypyrimidine tract (CCTTTC) had a slight effect on EoPV IRES activity. Furthermore, mutations of the RAAA motif led to a decrease in IRES activity of approximately 40 % in vitro, but these results were not supported by in vivo experiments. In conclusion, this study reveals that the EoPV IRES element is unique, although it has features in common with the type II IRESs.

scholarly journals Role of RNA Structure and Susceptibility to RNase E in Regulation of a Cold Shock mRNA, cspA mRNA

2007 ◽  
Vol 189 (12) ◽  
pp. 4353-4358 ◽  
Author(s):  
Janet S. Hankins ◽  
Christopher Zappavigna ◽  
Annie Prud'homme-Généreux ◽  
George A. Mackie
Keyword(s):  
Rna Structure ◽  
Cold Shock ◽  
Translational Efficiency ◽  
Rnase E ◽  
Temperature Dependent ◽  
Stem Loop ◽  
Differential Stability

ABSTRACT Degradation of the cspA mRNA in vivo is very rapid at temperatures greater than 30°C and is moderately dependent on RNase E. Investigations in vitro show that degradosomes prepared from normal or cold-shocked cultures cleave the cspA mRNA preferentially at a single site in vitro between two stem-loops ∼24 residues 3′ to the termination codon and ∼31 residues from the 3′ end. The site of cleavage is independent of the temperature and largely independent of the phosphorylation status of the 5′ end of cspA mRNA. A 5′ stem-loop, potential occlusion of the initiation and termination codons, temperature-dependent translational efficiency, and the position of the RNase E cleavage site can explain the differential stability of the cspA mRNA.

β-blockade abolishes the augmented cardiac tPA release induced by transactivation of heterodimerised bradykinin receptor-2 and β2-adrenergic receptor in vivo

2014 ◽  
Vol 112 (11) ◽  
pp. 951-959 ◽  
Author(s):  
Morten Eriksen ◽  
Arnfinn Ilebekk ◽  
Alessandro Cataliotti ◽  
Cathrine Rein Carlson ◽  
Torstein Lyberg ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Sympathetic Nerves ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Adrenergic Stimulation ◽  
Β2 Adrenergic Receptor ◽  
Β Blocker

SummaryBradykinin (BK) receptor-2 (B2R) and β2-adrenergic receptor (β2AR) have been shown to form heterodimers in vitro. However, in vivo proofs of the functional effects of B2R-β2AR heterodimerisation are missing. Both BK and adrenergic stimulation are known inducers of tPA release. Our goal was to demonstrate the existence of B2R-β2AR heterodimerisation in myocardium and to define its functional effect on cardiac release of tPA in vivo. We further investigated the effects of a non-selective β-blocker on this receptor interplay. To investigate functional effects of B2R-β2AR heterodimerisation (i. e. BK transactivation of β2AR) in vivo, we induced serial electrical stimulation of cardiac sympathetic nerves (SS) in normal pigs that underwent concomitant BK infusion. Both SS and BK alone induced increases in cardiac tPA release. Importantly, despite B2R desensitisation, simultaneous BK infusion and SS (BK+SS) was characterised by 2.3 ± 0.3-fold enhanced tPA release compared to SS alone. When β-blockade (propranolol) was introduced prior to BK+SS, tPA release was inhibited. A persistent B2R-β2AR heterodimer was confirmed in BK-stimulated and nonstimulated left ventricular myocardium by immunoprecipitation studies and under non-reducing gel conditions. All together, these results strongly suggest BK transactivation of β2AR leading to enhanced β2AR-mediated release of tPA. Importantly, non-selective β-blockade inhibits both SS-induced release of tPA and the functional effects of B2R-β2AR heterodimerisation in vivo, which may have important clinical implications.

scholarly journals Role of the 3′ tRNA-Like Structure in Tobacco Mosaic Virus Minus-Strand RNA Synthesis by the Viral RNA-Dependent RNA Polymerase In Vitro

2000 ◽  
Vol 74 (24) ◽  
pp. 11671-11680 ◽  
Author(s):  
T. A. M. Osman ◽  
C. L. Hemenway ◽  
K. W. Buck
Keyword(s):  
Rna Polymerase ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Untranslated Region ◽  
Rna Synthesis ◽  
Central Core ◽  
Minus Strand ◽  
Stem Loop ◽  
Polymerase Binding

ABSTRACT A template-dependent RNA polymerase has been used to determine the sequence elements in the 3′ untranslated region of tobacco mosaic virus RNA that are required for promotion of minus-strand RNA synthesis and binding to the RNA polymerase in vitro. Regions which were important for minus-strand synthesis were domain D1, which is equivalent to a tRNA acceptor arm; domain D2, which is similar to a tRNA anticodon arm; an upstream domain, D3; and a central core, C, which connects domains D1, D2, and D3 and determines their relative orientations. Mutational analysis of the 3′-terminal 4 nucleotides of domain D1 indicated the importance of the 3′-terminal CA sequence for minus-strand synthesis, with the sequence CCCA or GGCA giving the highest transcriptional efficiency. Several double-helical regions, but not their sequences, which are essential for forming pseudoknot and/or stem-loop structures in domains D1, D2, and D3 and the central core, C, were shown to be required for high template efficiency. Also important were a bulge sequence in the D2 stem-loop and, to a lesser extent, a loop sequence in a hairpin structure in domain D1. The sequence of the 3′ untranslated region upstream of domain D3 was not required for minus-strand synthesis. Template-RNA polymerase binding competition experiments showed that the highest-affinity RNA polymerase binding element region lay within a region comprising domain D2 and the central core, C, but domains D1 and D3 also bound to the RNA polymerase with lower affinity.

Identification of rpo30, a vaccinia virus RNA polymerase gene with structural similarity to a eucaryotic transcription elongation factor

1990 ◽  
Vol 10 (10) ◽  
pp. 5433-5441
Author(s):  
B Y Ahn ◽  
P D Gershon ◽  
E V Jones ◽  
B Moss
Keyword(s):  
Rna Polymerase ◽  
Vaccinia Virus ◽  
Rna Polymerase Ii ◽  
Elongation Factor ◽  
Viral Rna ◽  
In Vitro Translation ◽  
Virus Protein ◽  
Transcriptional Elongation

Eucaryotic transcription factors that stimulate RNA polymerase II by increasing the efficiency of elongation of specifically or randomly initiated RNA chains have been isolated and characterized. We have identified a 30-kilodalton (kDa) vaccinia virus-encoded protein with apparent homology to SII, a 34-kDa mammalian transcriptional elongation factor. In addition to amino acid sequence similarities, both proteins contain C-terminal putative zinc finger domains. Identification of the gene, rpo30, encoding the vaccinia virus protein was achieved by using antibody to the purified viral RNA polymerase for immunoprecipitation of the in vitro translation products of in vivo-synthesized early mRNA selected by hybridization to cloned DNA fragments of the viral genome. Western immunoblot analysis using antiserum made to the vaccinia rpo30 protein expressed in bacteria indicated that the 30-kDa protein remains associated with highly purified viral RNA polymerase. Thus, the vaccinia virus protein, unlike its eucaryotic homolog, is an integral RNA polymerase subunit rather than a readily separable transcription factor. Further studies showed that the expression of rpo30 is regulated by dual early and later promoters.

Tissue specificity of type I collagen gene expression is determined at both transcriptional and post-transcriptional levels

1984 ◽  
Vol 4 (9) ◽  
pp. 1843-1852
Author(s):  
R J Focht ◽  
S L Adams
Keyword(s):  
Gene Expression ◽  
Rna Structure ◽  
Type I Collagen ◽  
Translational Efficiency ◽  
Type I ◽  
Collagen Gene ◽  
Differentiated Cells ◽  
Collagen Gene Expression

We analyzed the control of type I collagen synthesis in four kinds of differentiated cells from chicken embryos which synthesize very different amounts of the protein. Tendon, skin, and smooth muscle cells were found to have identical amounts of type I collagen RNAs; however, the RNAs had inherently different translatabilities, which were observed both in vivo and in vitro. Chondrocytes also had substantial amounts of type I collagen RNAs, even though they directed no detectable synthesis of the protein either in vivo or in vitro. Type I collagen RNAs in chondrocytes display altered electrophoretic mobilities, suggesting that in these cells the reduction in translational efficiency may be mediated in part by changes in the RNA structure. These data indicate that control of type I collagen gene expression is a complex process which is exerted at both transcriptional and post-transcriptional levels.

Demonstration of hysteresis in refractoriness of canine ventricular myocardium

1988 ◽  
Vol 255 (6) ◽  
pp. H1342-H1348
Author(s):  
C. Giorgi ◽  
M. Vermeulen ◽  
R. Cardinal ◽  
P. Savard ◽  
R. Nadeau ◽  
...  
Keyword(s):  
Pulse Width ◽  
Cycle Length ◽  
Ventricular Myocardium ◽  
Ventricular Muscle ◽  
Cycle Lengths ◽  
Long Pulse ◽  
Basic Cycle Length ◽  
Canine Ventricular Myocardium

The properties and determinants of hysteresis during ventricular effective refractory period (VERP) measurements by an extrastimulus technique were determined in 15 anesthetized open-chest dogs as well as in isolated ventricular muscle (n = 6). VERP was determined both by decreasing the S1-S2 interval and also by increasing S1S2. Hysteresis was then calculated by subtracting the VERP obtained with the decreasing S1S2 from the VERP obtained with the increasing S1S2. The effects of basic cycle length, pulse width, stimulation intensity, and the number of basic drives on VERP and hysteresis were evaluated. VERP was shorter for long pulse width, high stimulation intensities, and shorter basic cycle lengths. These modifications were not associated with significant changes of hysteresis. VERP was shorter during decreasing S1S2 than during increasing S1S2. Hysteresis was greater with 6 basic drive cycles than with 12 (P less than 0.001) in both in vivo and in vitro preparations. The data suggest that 1) hysteresis occurs during VERP measurements; 2) hysteresis is independent of stimulation modality; and 3) hysteresis decreases with the number of basic drive cycles.

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