A Dictyostelium prespore-specific gene is transcriptionally repressed by DIF in vitro

One important role of DIF, the stalk cell-specific inducer of Dictyostelium, may be to divert cells from the spore cell pathway of differentiation. The D19 gene encodes an mRNA which is highly enriched in prespore over prestalk cells in the migratory slug. We show, using a mutant defective in DIF accumulation, that the concentration of D19, and several other prespore mRNA sequences, decreases in the presence of exogenous DIF. There is evidence that both transcriptional and post-transcriptional controls operate to regulate expression of these genes. We have performed in vitro nuclear transcription and mRNA half-life analyses, and find that DIF acts at the transcriptional level to repress the accumulation of the D19 mRNA.

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Hormonal regulation of cytochrome P450 aromatase mRNA stability in non-luteinizing bovine granulosa cells in vitro

Journal of Endocrinology ◽

10.1677/joe.1.06827 ◽

2006 ◽

Vol 190 (1) ◽

pp. 107-115 ◽

Cited By ~ 15

Author(s):

Malha Sahmi ◽

Edmir S Nicola ◽

Christopher A Price

Keyword(s):

Cytochrome P450 ◽

Granulosa Cells ◽

Half Life ◽

Hormonal Regulation ◽

Hormonal Control ◽

Transcriptional Level ◽

P450 Aromatase ◽

Cytochrome P450 Aromatase ◽

Mrna Half Life

In the present study, we determined the potential for post-transcriptional regulation of cytochrome P450 aromatase (Cyp19), cytochrome P450 side-chain cleavage (Cyp11a) and 17β-hydroxysteroid dehydrogenase I (Hsd17b1) mRNA. Bovine granulosa cells were cultured in non-luteinizing conditions that permit long-term oestradiol secretion. Half-lives of mRNA were measured by Northern and/or reverse transcriptase (RT)-PCR after inhibition of gene transcription. In FSH-stimulated cells, the Cyp11a and Hsd17b1 mRNAs had half-lives greater than 12 h. The half-life of Cyp19 mRNA was significantly shorter at 3 h. The addition of the translation inhibitor cycloheximide to FSH-stimulated cells significantly increased Cyp19 mRNA half-life to approximately 12 h. Stimulation of cells with insulin resulted in Cyp19 mRNA half-life that was double (P<0.05) that in FSH-stimulated cells. We conclude that bovine Cyp19 mRNA is very labile under physiological conditions, and that Cyp19 expression is under hormonal control at a post-transcriptional level.

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The dyskerin ribonucleoprotein complex as an OCT4/SOX2 coactivator in embryonic stem cells

eLife ◽

10.7554/elife.03573 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 21

Author(s):

Yick W Fong ◽

Jaclyn J Ho ◽

Carla Inouye ◽

Robert Tjian

Keyword(s):

Stem Cell ◽

Es Cells ◽

Embryonic Stem ◽

In Vitro Transcription ◽

Specific Gene ◽

Transcriptional Level ◽

Ips Cell ◽

Ribonucleoprotein Complex ◽

Transcription System

Acquisition of pluripotency is driven largely at the transcriptional level by activators OCT4, SOX2, and NANOG that must in turn cooperate with diverse coactivators to execute stem cell-specific gene expression programs. Using a biochemically defined in vitro transcription system that mediates OCT4/SOX2 and coactivator-dependent transcription of the Nanog gene, we report the purification and identification of the dyskerin (DKC1) ribonucleoprotein complex as an OCT4/SOX2 coactivator whose activity appears to be modulated by a subset of associated small nucleolar RNAs (snoRNAs). The DKC1 complex occupies enhancers and regulates the expression of key pluripotency genes critical for self-renewal in embryonic stem (ES) cells. Depletion of DKC1 in fibroblasts significantly decreased the efficiency of induced pluripotent stem (iPS) cell generation. This study thus reveals an unanticipated transcriptional role of the DKC1 complex in stem cell maintenance and somatic cell reprogramming.

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Mixed tailing by TENT4A and TENT4B shields mRNA from rapid deadenylation

Science ◽

10.1126/science.aam5794 ◽

2018 ◽

Vol 361 (6403) ◽

pp. 701-704 ◽

Cited By ~ 43

Author(s):

Jaechul Lim ◽

Dongwan Kim ◽

Young-suk Lee ◽

Minju Ha ◽

Mihye Lee ◽

...

Keyword(s):

Gene Regulation ◽

Half Life ◽

Messenger Rna ◽

Mrna Translation ◽

Posttranscriptional Gene Regulation ◽

And Function ◽

Mrna Half Life ◽

In Cells

RNA tails play integral roles in the regulation of messenger RNA (mRNA) translation and decay. Guanylation of the poly(A) tail was discovered recently, yet the enzymology and function remain obscure. Here we identify TENT4A (PAPD7) and TENT4B (PAPD5) as the enzymes responsible for mRNA guanylation. Purified TENT4 proteins generate a mixed poly(A) tail with intermittent non-adenosine residues, the most common of which is guanosine. A single guanosine residue is sufficient to impede the deadenylase CCR4-NOT complex, which trims the tail and exposes guanosine at the 3′ end. Consistently, depletion of TENT4A and TENT4B leads to a decrease in mRNA half-life and abundance in cells. Thus, TENT4A and TENT4B produce a mixed tail that shields mRNA from rapid deadenylation. Our study unveils the role of mixed tailing and expands the complexity of posttranscriptional gene regulation.

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Glucocorticoids regulate NHE-3 transcription in OKP cells

AJP Renal Physiology ◽

10.1152/ajprenal.1996.270.1.f164 ◽

1996 ◽

Vol 270 (1) ◽

pp. F164-F169 ◽

Cited By ~ 10

Author(s):

M. Baum ◽

M. Amemiya ◽

V. Dwarakanath ◽

R. J. Alpern ◽

O. W. Moe

Keyword(s):

Gene Transcription ◽

Half Life ◽

Time Course ◽

In Vitro Transcription ◽

Mrna Abundance ◽

Proton Secretion ◽

Threefold Increase ◽

Mrna Half Life ◽

Synthetic Glucocorticoid

OKP cells express NHE-3, an amiloride-resistant Na+/H+ antiporter, which is likely an isoform responsible for apical proton secretion by the proximal tubule. We have previously shown that an amiloride-resistant Na+/H+ antiporter in OKP cells is regulated by dexamethasone, a synthetic glucocorticoid. The purpose of the present study was to examine the mechanism for the glucocorticoid-mediated increase in Na+/H+ antiporter activity. Incubation of OKP cells with 10(-6) M dexamethasone resulted in a two- to threefold increase in NHE-3 mRNA abundance. This increase was seen after 4 h of incubation with dexamethasone, a time course similar to that found for Na+/H+ antiporter activity. To examine the mechanism for the increase in NHE-3 mRNA abundance, mRNA half-life and in vitro transcription experiments were performed. NHE-3 mRNA had a half-life of 8 h in control and dexamethasone-treated cells. The rate of in vitro transcription was 1.8-fold greater when OKP cells were treated with dexamethasone. These data suggest that the glucocorticoid-mediated increase in Na+/H+ antiporter activity is due to an increase in NHE-3 gene transcription.

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Evaluation of the Role of the Bvg Intermediate Phase in Bordetella pertussis during Experimental Respiratory Infection

Infection and Immunity ◽

10.1128/iai.73.2.748-760.2005 ◽

2005 ◽

Vol 73 (2) ◽

pp. 748-760 ◽

Cited By ~ 37

Author(s):

Nuria Vergara-Irigaray ◽

Alberto Chávarri-Martínez ◽

Juan Rodríguez-Cuesta ◽

Jeff F. Miller ◽

Peggy A. Cotter ◽

...

Keyword(s):

Respiratory Tract ◽

Bordetella Pertussis ◽

Wild Type Strain ◽

Intermediate Phase ◽

Transcriptional Level ◽

Wild Type ◽

Environmental Signals ◽

Time Point

ABSTRACT The BvgAS system of Bordetella pertussis was traditionally considered to mediate a transition between two phenotypic phases (Bvg+ and Bvg−) in response to environmental signals. We characterized a third state, the intermediate (Bvgi) phase, which can be induced by introducing a 1-bp substitution into bvgS (the bvgS-I1 mutation) or by growing B. pertussis under conditions intermediate between those leading to the Bvg+ and Bvg− phases. Like B. bronchiseptica, B. pertussis displays in its Bvgi phase a characteristic colony morphology and hemolytic activity and expresses a Bvgi-phase-specific polypeptide called BipA, whose synthesis is regulated by bvgAS at the transcriptional level. Based on our results, we hypothesize that the Bvgi phase of B. pertussis may be involved in facilitating transmission between hosts. Thus, a B. pertussis mutant carrying the bvgS-I1 mutation (GMT1i) persisted at wild-type levels only in the upper murine respiratory tract. Interestingly, a bipA deletion derivative of GMT1i displayed a reduced ability to colonize the nasal cavity of mice compared with GMT1i. However, in experimental mixed infections GMT1i expressing the Bvgi phase could establish an initial colonization in the nose and trachea of mice as efficiently as GMT1, but the wild-type strain outcompeted GMT1i at a later time point at all sites of the respiratory tract, suggesting that the Bvgi phase does not serve as a phenotypic phase specialized in colonization. Finally, even though B. pertussis expresses in vitro the Bvgi phase at the human nasal temperature, anti-BipA antibodies were undetectable in a large collection of sera from pertussis patients.

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Abstract 12880: Up-Regulation of Microrna-208b Contributes to Diabetic Myocardial Fibrosis in Mouse

Circulation ◽

10.1161/circ.130.suppl_2.12880 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Zhi Xin Shan ◽

Lin lin Guo ◽

Jie ning Zhu ◽

Qiu xiong Lin ◽

Chun yu Deng ◽

...

Keyword(s):

Myocardial Fibrosis ◽

Recombinant Adenovirus ◽

Cardiac Fibroblasts ◽

Transcriptional Level ◽

Dependent Manner ◽

Genes Expression ◽

Diabetic Myocardium

MicroRNAs play important roles in myocardial fibrosis during diabetic cardiomyopathy. The present study aimed to investigate the role of microRNA-208b (miR-208b) in diabetic myocardial fibrosis. Compared to the db/m control mice, Smad3 was activated , fibrosis-related genes expression were significantly up-regulated, and miRNAs were dysregulated in the myocardium of the 16-week-old diabetic db/db mice. miR-208b was confirmed up-regulated in the db/db diabetic myocardium in vivo and in mouse cardiomyocytes and cardiac fibroblasts after treatment with Ang-II, TGF-β and high glucose/glucose oxidase (HG/Go) in vitro , respectively. By using recombinant adenovirus expressing CD63-GFP, rAd-CD63-GFP, we infected neonatal mouse cardiomyocytes with rAd-CD63-GFP and tracked the secreted exosomes with GFP. We found that miR-208b was increased in the secreted exosomes from HG/Go-treated cardiomyocytes, and the exosomes with increased miR-208b could enhance fibrosis associated Col1a1, α-SMA and CTGF expressions in cardiac fibroblasts. Transfection of miR-208b mimic could increase Col1a1, α-SMA and CTGF expression in a dose-dependent manner in cardiac fibroblasts. However, blockage of miR-208b could inhibit fibrosis related genes expression. Mtf2 and Pgrmc1 were verified modulated by miR-208b at post transcriptional level in vitro . Consistently, Mtf2 and Pgrmc1 expressions were decreased in the diabetic myocardium, and knockdown of Mtf2 or Pgrmc1could increase fibrosis related genes expression in cardiac fibroblasts. Smad3 inhibitor, Naringenin, could dramatically inhibit miR-208b expression in cardiac fibroblasts. Taken together, we demonstrated that miR-208b was up-regulated in diabetic fibrotic myocardium, Mtf2 and Pgrmc1 mediated the effect of miR-208b on enhancing Col1a1, α-SMA and CTGF expression in diabetic myocardial fibrosis.

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ROLE OF THE ERYTHROCYTES IN TRANSPORT AND METABOLISM OF 4-14C-CORTISOL

Acta Endocrinologica ◽

10.1530/acta.0.0370348 ◽

1961 ◽

Vol 37 (3) ◽

pp. 348-352 ◽

Cited By ~ 11

Author(s):

A. Vermeulen

Keyword(s):

Half Life ◽

Red Cells ◽

Total Blood ◽

Biological Half Life ◽

Blood Radioactivity

ABSTRACT After infusion of 4-14C-cortisol, radioactivity associated with red cells amounts to 16 – 37 % of total blood radioactivity and its biological half life is similar to the half life of plasma radioactivity. Cortisol is not metabolized by erythrocytes in vitro. Our data suggest that the corticoids are adsorbed at the red cells surface.

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cdk1- and cdk2-Mediated Phosphorylation of MyoD Ser200 in Growing C2 Myoblasts: Role in Modulating MyoD Half-Life and Myogenic Activity

Molecular and Cellular Biology ◽

10.1128/mcb.19.4.3167 ◽

1999 ◽

Vol 19 (4) ◽

pp. 3167-3176 ◽

Cited By ~ 81

Author(s):

Magali Kitzmann ◽

Marie Vandromme ◽

Valerie Schaeffer ◽

Gilles Carnac ◽

Jean-Claude Labbé ◽

...

Keyword(s):

Half Life ◽

Site Directed Mutagenesis ◽

Cyclin B ◽

Wild Type ◽

E Box ◽

Integral Role ◽

Phosphopeptide Mapping

ABSTRACT We have examined the role of protein phosphorylation in the modulation of the key muscle-specific transcription factor MyoD. We show that MyoD is highly phosphorylated in growing myoblasts and undergoes substantial dephosphorylation during differentiation. MyoD can be efficiently phosphorylated in vitro by either purified cdk1-cyclin B or cdk1 and cdk2 immunoprecipitated from proliferative myoblasts. Comparative two-dimensional tryptic phosphopeptide mapping combined with site-directed mutagenesis revealed that cdk1 and cdk2 phosphorylate MyoD on serine 200 in proliferative myoblasts. In addition, when the seven proline-directed sites in MyoD were individually mutated, only substitution of serine 200 to a nonphosphorylatable alanine (MyoD-Ala200) abolished the slower-migrating hyperphosphorylated form of MyoD, seen either in vitro after phosphorylation by cdk1-cyclin B or in vivo following overexpression in 10T1/2 cells. The MyoD-Ala200 mutant displayed activity threefold higher than that of wild-type MyoD in transactivation of an E-box-dependent reporter gene and promoted markedly enhanced myogenic conversion and fusion of 10T1/2 fibroblasts into muscle cells. In addition, the half-life of MyoD-Ala200 protein was longer than that of wild-type MyoD, substantiating a role of Ser200 phosphorylation in regulating MyoD turnover in proliferative myoblasts. Taken together, our data show that direct phosphorylation of MyoD Ser200 by cdk1 and cdk2 plays an integral role in compromising MyoD activity during myoblast proliferation.

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Mechanism for Stabilizing mRNAs Involved in Methanol-Dependent Methanogenesis of Cold-Adaptive Methanosarcina mazei zm-15

Applied and Environmental Microbiology ◽

10.1128/aem.03495-13 ◽

2013 ◽

Vol 80 (4) ◽

pp. 1291-1298 ◽

Cited By ~ 13

Author(s):

Yi Cao ◽

Jie Li ◽

Na Jiang ◽

Xiuzhu Dong

Keyword(s):

Half Life ◽

Content Type ◽

Methanosarcina Mazei ◽

Reverse Transcription Quantitative Pcr ◽

Aceticlastic Methanogenesis ◽

The Stability ◽

Zoige Wetland ◽

Mrna Half Life

ABSTRACTMethylotrophic methanogenesis predominates at low temperatures in the cold Zoige wetland in Tibet. To elucidate the basis of cold-adapted methanogenesis in these habitats,Methanosarcina mazeizm-15 was isolated, and the molecular basis of its cold activity was studied. For this strain, aceticlastic methanogenesis was reduced 7.7-fold during growth at 15°C versus 30°C. Methanol-derived methanogenesis decreased only 3-fold under the same conditions, suggesting that it is more cold adaptive. Reverse transcription-quantitative PCR (RT-qPCR) detected <2-fold difference in the transcript abundances ofmtaA1,mtaB1, andmtaC1, the methanol methyltransferase (Mta) genes, in 30°C versus 15°C culture, whileackAandptamRNAs, encoding acetate kinase (Ack) and phosphotransacetylase (Pta) in aceticlastic methanogenesis, were 4.5- and 6.8-fold higher in 30°C culture than in 15°C culture. Thein vivohalf-lives ofmtaA1andmtaC1B1mRNAs were similar in 30°C and 15°C cultures. However, thepta-ackAmRNA half-life was significantly reduced in 15°C culture compared to 30°C culture. Using circularized RNA RT-PCR, large 5′ untranslated regions (UTRs) (270 nucleotides [nt] and 238 nt) were identified formtaA1andmtaC1B1mRNAs, while only a 27-nt 5′ UTR was present in thepta-ackAtranscript. Removal of the 5′ UTRs significantly reduced thein vitrohalf-lives ofmtaA1andmtaC1B1mRNAs. Remarkably, fusion of themtaA1ormtaC1B15′ UTRs topta-ackAmRNA increased itsin vitrohalf-life at both 30°C and 15°C. These results demonstrate that the large 5′ UTRs significantly enhance the stability of the mRNAs involved in methanol-derived methanogenesis in the cold-adaptiveM. mazeizm-15.

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