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1.
Phys Rev Lett ; 127(17): 171801, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34739288

RESUMO

Using a dataset of 6.32 fb^{-1} of e^{+}e^{-} annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay D_{s}^{+}→τ^{+}ν_{τ} via τ^{+}→e^{+}ν_{e}ν[over ¯]_{τ}, and find B_{D_{s}^{+}→τ^{+}ν_{τ}}=(5.27±0.10±0.12)×10^{-2}, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with f_{D_{s}^{+}} from lattice quantum chromodynamics calculations or the |V_{cs}| from the CKMfitter group, we extract |V_{cs}|=0.978±0.009±0.012 and f_{D_{s}^{+}}=(251.1±2.4±3.0) MeV, respectively. Combining our result with the world averages of B_{D_{s}^{+}→τ^{+}ν_{τ}} and B_{D_{s}^{+}→µ^{+}ν_{µ}}, we obtain the ratio of the branching fractions B_{D_{s}^{+}→τ^{+}ν_{τ}}/B_{D_{s}^{+}→µ^{+}ν_{µ}}=9.72±0.37, which is consistent with the standard model prediction of lepton flavor universality.

2.
Phys Rev Lett ; 127(12): 121802, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34597097

RESUMO

The absolute branching fraction of Λ→pµ^{-}ν[over ¯]_{µ} is reported for the first time based on an e^{+}e^{-} annihilation sample of 10×10^{9} J/ψ events collected with the BESIII detector at sqrt[s]=3.097 GeV. The branching fraction is determined to be B(Λ→pµ^{-}ν[over ¯]_{µ})=[1.48±0.21(stat)±0.08(syst)]×10^{-4}, which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Λ→pe^{-}ν[over ¯]_{e}), we obtain the ratio {[Γ(Λ→pµ^{-}ν[over ¯]_{µ})]/[Γ(Λ→pe^{-}ν[over ¯]_{e})]} to be 0.178±0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Λ→pµ^{-}ν[over ¯]_{µ} and Λ[over ¯]→p[over ¯]µ^{+}ν_{µ} is also determined, and no evidence for CP violation is found.

3.
Phys Rev Lett ; 127(13): 131801, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34623854

RESUMO

Using 2.93 fb^{-1} of e^{+}e^{-} collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} semileptonic decay is presented. The statistical significance of the decay D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is greater than 10σ. The branching fraction of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is measured to be (1.09±0.13_{-0.16}^{+0.09}±0.12)×10^{-3}. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K_{1}(1270)^{-}→K^{-}π^{+}π^{-}. The fraction of longitudinal polarization in D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is determined for the first time to be 0.50±0.19_{stat}±0.08_{syst}.

4.
Biochim Biophys Acta ; 1518(1-2): 47-56, 2001 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-11267658

RESUMO

We have previously shown that in response to treatment with HgCl(2), the adult mouse liver exhibits both transcriptional and translational regulation of the acute phase response genes. In this study we asked whether the heavy metal treatment affects the regulation of the C/EBP transcription factors which play a key role in regulation of the acute phase response gene. Our studies have shown that the AGP gene is transcriptionally activated while transcription of the CCAAT/enhancer-binding trans-activating protein (C/EBP)alpha gene is slightly down-regulated and that of the C/EBPbeta gene does not respond. Both the C/EBPalpha and C/EBPbeta mRNAs produce multiple isoforms possibly by alternative translation initiation (ATI) of multiple internal AUG initiation sites. The C/EBPbeta mRNA appears to be stabilized. Although similar regulatory processes occur in response HgCl(2) vs. LPS, our data suggest that the translational processes (ATI) are differentially affected. In addition, a major difference lies in the fact that the C/EBPbeta gene is not transcriptionally activated by HgCl(2). Our data show decreased binding activity and pool levels of the C/EBPalpha isoform (p42(C/EBPalpha)) and increased binding activity and pool levels of C/EBPbeta isoform (p35(C/EBPbeta)) in response to HgCl(2). We propose that this isoform may be involved in the regulation of AGP gene expression in response to heavy metals and that there is a significant difference between the HgCl(2)-mediated and LPS-mediated inflammatory response.


Assuntos
Processamento Alternativo , Proteína alfa Estimuladora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/genética , Regulação da Expressão Gênica , Cloreto de Mercúrio/farmacologia , Orosomucoide/genética , Transcrição Genética , Animais , Proteína alfa Estimuladora de Ligação a CCAAT/metabolismo , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Células COS , Chlorocebus aethiops , DNA/metabolismo , Vetores Genéticos , Lipopolissacarídeos/farmacologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Regiões Promotoras Genéticas , Isoformas de Proteínas/genética , Transfecção
5.
J Korean Med Sci ; 14(5): 497-501, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10576144

RESUMO

The present study was aimed at investigating the regulation of atrial natriuretic peptide (ANP) system in association with either enhanced or attenuated activity of the renin-angiotensin system (RAS). The cardiac tissue mRNA and peptide levels of ANP were measured in rats with two-kidney, one clip (2K1C) or deoxycorticosterone acetate (DOCA)-salt hypertension. Plasma renin concentration was increased in 2K1C hypertension along with increases of renin mRNA and protein contents in the clipped kidney. On the contrary, it was suppressed in DOCA-salt hypertension along with decreases of renin mRNA and protein contents in the remaining kidney. The plasma ANP concentration was similarly increased in both models of hypertension. The cardiac tissue ANP contents were not significantly changed, but the tissue ANP mRNA levels were upregulated in the hypertrophied heart in these two models of hypertension. It is suggested that the cardiac ANP system is transcriptionally enhanced by cardiac hypertrophy associated with hypertension, independent of the systemic RAS.


Assuntos
Fator Natriurético Atrial/metabolismo , Hipertensão/metabolismo , Renina/sangue , Renina/genética , Animais , Desoxicorticosterona , Regulação da Expressão Gênica , Hipertensão/induzido quimicamente , Masculino , Miocárdio/patologia , Tamanho do Órgão , Peptídeos , RNA Mensageiro/análise , Ratos , Ratos Sprague-Dawley , Sistema Renina-Angiotensina/fisiologia
6.
Mol Cell Endocrinol ; 152(1-2): 125-36, 1999 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-10432230

RESUMO

During development, the insulin-like growth factor I (IGF-I) gene is expressed in a tissue specific manner; however, the molecular mechanisms governing its developmental regulation remain poorly defined. To examine the hypothesis that expression of the growth hormone (GH) receptor accounts, in part, for the tissue specific expression of the IGF-I gene during development, the developmental regulation of IGF-I and GH receptor gene expression in rat tissues was examined. The level of IGF-I and GH receptor mRNA was quantified in RNA prepared from rats between day 17 of gestation (E17) and 17 months of age (17M) using an RNase protection assay. Developmental regulation of IGF-I gene expression was tissue specific with four different patterns of expression seen. In liver, IGF-I mRNA levels increased markedly between E17 and postnatal day 45 (P45) and declined thereafter. In contrast, in brain, skeletal muscle and testis, IGF-I mRNA levels decreased between P5 and 4M but were relatively unchanged thereafter. In heart and kidney, a small increase in IGF-I mRNA levels was observed between the early postnatal period and 4 months, whereas in lung, minimal changes were observed during development. The changes in GH receptor mRNA levels were, in general, coordinate with the changes in IGF-I mRNA levels, except in skeletal muscle. Interestingly, quantification of GH receptor levels by Western blot analysis in skeletal muscle demonstrated changes coordinate with IGF-I mRNA levels. The levels of the proteins which mediate GH receptor signaling (STAT1, -3, and -5, and JAK2) were quantified by Western blot analysis. These proteins also are expressed in a tissue specific manner during development. In some cases, the pattern of expression was coordinate with IGF-I gene expression, whereas in others it was discordant. To further define molecular mechanisms for the developmental regulation of IGF-I gene expression, protein binding to IGFI-FP1, a protein binding site that is in the major promoter of the rat IGF-I gene and is important for basal promoter activity in vitro, was examined. Gel shift analyses using a 34-base pair oligonucleotide that contained IGFI-FP1 did not demonstrate changes in protein binding that paralleled those in IGF-I gene expression, suggesting that protein binding to IGFI-FP1 does not contribute to the developmental regulation of IGF-I gene expression, at least in brain and liver. In summary, the present studies demonstrate coordinate expression of the IGF-I gene and GH receptor during development and suggest that GH receptor expression contributes to the tissue specific expression of the IGF-I gene during development.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Fator de Crescimento Insulin-Like I/genética , Receptores da Somatotropina/genética , Animais , Western Blotting , Desenvolvimento Embrionário e Fetal/genética , Especificidade de Órgãos , Regiões Promotoras Genéticas , RNA Mensageiro/análise , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley
7.
Mol Biol Cell ; 9(6): 1479-94, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9614188

RESUMO

The CCAAT/enhancer binding protein alpha (C/EBPalpha) and CCAAT/enhancer binding protein beta (C/EBPbeta) mRNAs are templates for the differential translation of several isoforms. Immunoblotting detects C/EBPalphas with molecular masses of 42, 38, 30, and 20 kDa and C/EBPbetas of 35, 20, and approximately 8.5 kDa. The DNA-binding activities and pool levels of p42(C/EBPalpha) and p30(C/EBPalpha) in control nuclear extracts decrease significantly whereas the binding activity and protein levels of the 20-kDa isoforms increase dramatically with LPS treatment. Our studies suggest that the LPS response involves alternative translational initiation at specific in-frame AUGs, producing specific C/EBPalpha and C/EBPbeta isoform patterns. We propose that alternative translational initiation occurs by a leaky ribosomal scanning mechanism. We find that nuclear extracts from normal aged mouse livers have decreased p42(C/EBPalpha) levels and binding activity, whereas those of p20(C/EBPalpha) and p20(C/EBPbeta) are increased. However, translation of 42-kDa C/EBPalpha is not down-regulated on polysomes, suggesting that aging may affect its nuclear translocation. Furthermore, recovery of the C/EBPalpha- and C/EBPbeta-binding activities and pool levels from an LPS challenge is delayed significantly in aged mouse livers. Thus, aged livers have altered steady-state levels of C/EBPalpha and C/EBPbeta isoforms. This result suggests that normal aging liver exhibits characteristics of chronic stress and a severe inability to recover from an inflammatory challenge.


Assuntos
Envelhecimento/metabolismo , Proteínas de Ligação a DNA/metabolismo , Lipopolissacarídeos/farmacologia , Fígado/metabolismo , Proteínas Nucleares/metabolismo , Processamento Pós-Transcricional do RNA , Animais , Southern Blotting , Western Blotting , Proteínas Estimuladoras de Ligação a CCAAT , Células COS , Extratos Celulares , Núcleo Celular , Regulação da Expressão Gênica , Vetores Genéticos , Fígado/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Peso Molecular , Oligodesoxirribonucleotídeos/metabolismo , Orosomucoide/genética , Polirribossomos/metabolismo , Regiões Promotoras Genéticas , Transfecção
9.
Mol Cell Biol ; 16(5): 2295-306, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8628296

RESUMO

The mRNAs of the CCAAT/enhancer-binding trans-activator proteins (C/EBPalpha and C/EBPbeta) serve as templates for the differential translation of several isoforms which have specific transcriptional regulatory functions. By using an oligonucleotide corresponding to the C/EBP binding site of the mouse alpha1-acid glycoprotein promoter, we detected multiple forms of C/EBPalpha and C/EBP++ beta proteins in the mouse liver that have DNA-binding activity. By using specific antisera, we detected C/EBPalphas with molecular masses of 42, 38, 30, and 20 kDa that have DNA-binding activity. The pool levels of the 42- and 30-kDa isoforms were high in control nuclear extracts and decreased significantly after lipopolysaccharide (LPS) treatment. The binding activity and protein levels of the 20-kDa isoform are low in controls and increase dramatically after LPS treatment. C/EBPbeta isoforms with molecular masses of 35, 20, and 16 kDa were also detected. The 35-kDa pool level did not change whereas the 20-kDa isoform was strongly induced in response to LPS. Western (immunoblot) and Southwestern (DNA-protein) analyses show that p42 C/EBPalpha forms specific complexes with the alpha1-acid glycoprotein oligonucleotide in control nuclear extract and that p20 C/EBP beta forms complexes in LPS-treated liver. Our studies suggest that synthesis of specific C/EBPalpha and C/EBPbeta isoforms occurred in the normal liver in vivo and that LPS mediated a differential initiation and inhibition of translation at specific AUG sites within each mRNA. The qualitative and quantitative changes in C/EBPalpha and C/EBPbeta isoform pool levels suggest that LPS or an LPS-stimulated factor can regulate the selection of AUG start sites for both activation and repression of translation. This regulation appears to involve an LPS-mediated down-regulation of initiation at the first AUG codon of the 42-kDa C/EBPalpha and dramatic translational up-regulation at the fifth AUG codon of the 20-kDa C/EBPalpha and the third AUG codon of the 20-kDa C/EBPbeta. These regulatory events suggest the existence of proteins that may act as translational trans-acting factors.


Assuntos
Proteínas de Ligação a DNA/biossíntese , Expressão Gênica/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Fígado/metabolismo , Proteínas Nucleares/biossíntese , Biossíntese de Proteínas/efeitos dos fármacos , Fatores de Transcrição/biossíntese , Sequência de Aminoácidos , Animais , Sequência de Bases , Proteínas Estimuladoras de Ligação a CCAAT , Núcleo Celular/metabolismo , Eletroforese em Gel de Poliacrilamida , Soros Imunes , Immunoblotting , Cinética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Proteínas Nucleares/isolamento & purificação , Proteínas Nucleares/metabolismo , Oligodesoxirribonucleotídeos , Orosomucoide/biossíntese , Orosomucoide/genética , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/imunologia , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Transcrição Genética
10.
Mol Cell Endocrinol ; 114(1-2): 77-89, 1995 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-8674854

RESUMO

IGF-I gene transcription is regulated by two promoters--the major promoter which is active in all tissues and regulates transcription of IGF-I mRNAs that contain exon 1 and a second promoter which regulates transcription of IGF-I mRNAs that contain exon 2 and from which significant transcription is restricted to the liver. The major promoter is a TATAA-less promoter that lacks both a CAAT box and SP1 binding sites and that utilizes multiple transcription initiation sites. The current studies were designed to delineate the functional elements of the major promoter. Transient transfection assays using rat C6 glioma cells and rat dermal fibroblasts in primary culture demonstrated that basal activity of the major promoter was located between -18 (with +1 defined as the most 5' transcription initiation site in exon 1) and +78 of exon 1. DNase I footprinting, which was performed using nuclear extracts from rat C6 glioma cells, demonstrated protein binding to a sequence that extended from -10 to +9 (termed IGFI-FP1). In gel shift assays, binding of C6 cell nuclear proteins to a 34-basepair (bp) oligonucleotide that contained IGFI-FP1 resulted in the formation of three specific protein-DNA complexes. The functional role of protein binding to IGFI-FP1 was examined by mutating the sequences between either -4 and -2 or -9 and -7 in IGF-I-luciferase fusion genes that contained either 412 or 18 bp of 5'-flanking region and 302 bp of exon 1. Both of these mutations altered protein binding to IGFI-FP1 as demonstrated by gel shift analysis. Transfection of the wild-type and mutant fusion genes into C6 glioma cells demonstrated that mutation of the nucleotides between -4 and -2 decreased luciferase activity to approximately 50% of wild-type activity, whereas mutation of the nucleotides between -9 and -7 decreased luciferase activity to 11-35% of wild-type activity. These data demonstrate that: (i) basal activity of the major promoter of the rat IGF-I gene is localized to the region between -18 and +78 of exon 1; (ii) protein binding sites are present within this region of the major promoter; and (iii) protein binding to this region contributes to basal expression of the IGF-I gene.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Fator de Crescimento Insulin-Like I/genética , Regiões Promotoras Genéticas , Animais , Sequência de Bases , Linhagem Celular , Clonagem Molecular , DNA/genética , DNA/metabolismo , Proteínas de Ligação a DNA/genética , Expressão Gênica , Luciferases/genética , Luciferases/metabolismo , Dados de Sequência Molecular , Sondas de Oligonucleotídeos/genética , Ratos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transfecção
11.
J Biol Chem ; 268(21): 15681-8, 1993 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-8340393

RESUMO

alpha 1-Acid glycoprotein (AGP) is a major acute phase protein synthesized primarily by the liver. The AGP gene is transcriptionally activated in hepatocytes during the acute phase response to bacterial lipopolysaccharide. In this study, we analyzed an acute phase responsive element (APRE) located between nucleotide residues -127 to -104 relative to the transcription initiation site of the mouse AGP gene. Binding studies show that several trans-acting factors interact with the APRE. Using monospecific antibodies we demonstrate that three isoforms of the CCAAT/enhancer-binding protein (C/EBP) family, namely C/EBP alpha, C/EBP beta, and C/EBP delta, bind to the APRE. Furthermore, with liver nuclear protein from control animals, C/EPB alpha is the predominant form that binds to the APRE, whereas with nuclear proteins from acute phase-induced animals, C/EBP alpha is replaced by C/EBP beta. The mechanism of activation of the AGP gene during the acute phase response appears to involve an exchange of C/EBP alpha by C/EBP beta. C/EBP delta does not play a role in this reaction. Interestingly, the C/EBP binding site of the APRE partially overlaps a functional glucocorticoid responsive element. We present evidence that both purified C/EBP alpha and glucocorticoid receptor bind strongly to the APRE. By site-specific mutation, we have identified the C/EBP and glucocorticoid receptor binding sites in the APRE. These mutants were used in expression vectors to demonstrate that both C/EBP and glucocorticoid receptor are essential for maximal response to interleukin-6 and dexamethasone. These results demonstrate that the APRE is a composite binding site for multiple factors that are responsible for the transcriptional control of the mouse AGP. Finally, functional analyses indicate that C/EBP alpha, C/EBP beta, and C/EBP delta are strong transcriptional trans-activators of the AGP APRE in hepatoma cells. These data suggest that the regulatory activity of the C/EBP with the APRE in the liver may require interactions with adjacent proteins.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/metabolismo , Orosomucoide/genética , Receptores de Glucocorticoides/metabolismo , Fatores de Transcrição/metabolismo , Ativação Transcricional , Reação de Fase Aguda/genética , Reação de Fase Aguda/metabolismo , Animais , Sequência de Bases , Proteínas Estimuladoras de Ligação a CCAAT , Citocinas/fisiologia , Glucocorticoides/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Regiões Promotoras Genéticas , Sequências Reguladoras de Ácido Nucleico , Moldes Genéticos , Células Tumorais Cultivadas
12.
J Biol Chem ; 267(8): 5021-4, 1992 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-1371993

RESUMO

Eucaryotic organisms possess natural defense processes triggered by stress factors such as injury, infection, and inflammation. The acute phase response is an early defense mechanism during which striking changes in protein synthesis occur in the liver and other tissues. The altered expression of many acute phase protein genes is at the transcriptional level. Some of these genes have DNA binding sites for the CCAAT/enhancer binding protein (C/EBP) family of transcription factors. We report here that in vivo expression of three isoforms of C/EBP is dramatically changed during the acute phase response. The steady-state mRNA levels of C/EBP alpha decreased significantly in the liver, lung, and fat tissues of lipopolysaccharide (LPS)-treated mice; moreover, nuclear run-off transcription assays indicated a decrease in the rate of C/EBP alpha gene transcription in isolated liver nuclei. The steady-state levels of C/EBP beta and a new isoform, C/EBP delta, were dramatically increased in many tissues within 4 h following LPS treatment. The rates of transcription of these two genes were only minimally altered in liver but significantly increased in kidney nuclei isolated from stimulated animals. Thus, the C/EBP isoforms exhibit differential mechanisms in their responses to LPS in various tissues and are likely to play an important role in mediating the transcriptional activation of genes involved in the acute phase response.


Assuntos
Proteínas de Fase Aguda/genética , Proteínas de Ligação a DNA/genética , Proteínas Nucleares/genética , RNA Mensageiro/metabolismo , Transcrição Genética , Animais , Northern Blotting , Proteínas Estimuladoras de Ligação a CCAAT , Expressão Gênica , Lipopolissacarídeos/toxicidade , Fígado/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Especificidade de Órgãos , RNA/genética , RNA/isolamento & purificação , RNA Mensageiro/genética , Fatores de Transcrição/genética
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