RESUMEN
GFP is frequently used as a marker for tracking donor cells adoptively transplanted into recipient animals. The human ubiquitin C promoter (UBC)-driven-GFP transgenic mouse is a commonly used source of donor cells for this purpose. This mouse was initially generated in the C57BL/6 inbred strain and has been backcrossed into the BALB/cBy strain for over 11 generations. Both the C57BL/6 inbred and BALB/cBy congenic UBC-GFP lines are commercially available and have been widely distributed. These UBC-GFP lines can be a convenient resource for tracking donor cells in both syngenic MHC-matched and in allogenic MHC-mismatched studies as C57BL/6 (H-2b) and BALB/cBy (H-2d) have disparate MHC haplotypes. In this report, we surprisingly discover that the UBC-GFP BALB/cBy congenic mice still retain the H-2b MHC haplotype of their original C57BL/6 founder, suggesting that the UBC-GFP transgene integration site is closely linked to the MHC locus on chromosome 17. Using linear amplification-mediated PCR, we successfully map the UBC-GFP transgene to the MHC locus. This study highlights the importance and urgency of mapping the transgene integration site of transgenic mouse strains used in biomedical research. Furthermore, this study raises the possibility of alternative interpretations of previous studies using congenic UBC-GFP mice and focuses attention on the necessity for rigor and reproducibility in scientific research.
Asunto(s)
Cromosomas/genética , Proteínas Fluorescentes Verdes/genética , Complejo Mayor de Histocompatibilidad/genética , Mutagénesis Insercional/genética , Transgenes/genética , Ubiquitina C/genética , Animales , Haplotipos/genética , Ratones , Ratones Congénicos , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Regiones Promotoras Genéticas/genética , Reproducibilidad de los ResultadosRESUMEN
In situ hybridization (ISH) is a powerful tool that can be used to localize mRNA expression in tissue samples. Combining ISH with immunohistochemistry (IHC) to determine cell type provides cellular context of mRNA expression, which cannot be achieved with gene microarray or polymerase chain reaction. To study mRNA and protein expression on the same section we investigated the use of RNAscope® ISH in combination with fluorescent IHC on paraffin-embedded human brain tissue. We first developed a high-throughput, automated image analysis workflow for quantifying RNA puncta across the total cell population and within neurons identified by NeuN+ immunoreactivity. We then applied this automated analysis to tissue microarray (TMA) sections of middle temporal gyrus tissue (MTG) from neurologically normal and Alzheimer's Disease (AD) cases to determine the suitability of three commonly used housekeeping genes: ubiquitin C (UBC), peptidyl-prolyl cis-trans isomerase B (PPIB) and DNA-directed RNA polymerase II subunit RPB1 (POLR2A). Overall, we saw a significant decrease in total and neuronal UBC expression in AD cases compared to normal cases. Total expression results were validated with RT-qPCR using fresh frozen tissue from 5 normal and 5 AD cases. We conclude that this technique combined with our novel automated analysis pipeline provides a suitable platform to study changes in gene expression in diseased human brain tissue with cellular and anatomical context. Furthermore, our results suggest that UBC is not a suitable housekeeping gene in the study of post-mortem AD brain tissue.
Asunto(s)
Enfermedad de Alzheimer , Perfilación de la Expresión Génica/métodos , Genes Esenciales , Inmunohistoquímica/métodos , Hibridación Fluorescente in Situ/métodos , Anciano , Anciano de 80 o más Años , Ciclofilinas/análisis , ARN Polimerasas Dirigidas por ADN/análisis , Femenino , Ensayos Analíticos de Alto Rendimiento/métodos , Humanos , Masculino , Persona de Mediana Edad , ARN Mensajero/análisis , Transcriptoma , Ubiquitina C/análisis , Flujo de TrabajoRESUMEN
Accurate relative gene expression analysis by reverse transcription-quantitative polymerase chain reaction relies on the usage of suitable reference genes for data normalization. The RNA content of small extracellular vesicles including exosomes is growingly considered as cancer biomarkers. So, reliable relative quantification of exosomal messenger RNA (mRNA) is essential for cancer diagnosis and prognosis applications. However, suitable reference genes for accurate normalization of a target gene in exosomes derived from cancer cells are not depicted yet. Here, we analyzed the expression and stability of eight well-known reference genes namely GAPDH, B2M, HPRT1, ACTB, YWHAZ, UBC, RNA18S, and TBP in exosomes-isolated from the liver (Huh7, HepG2, PLC/PRF/5) and breast (SK-BR-3) cancer cell lines using five different algorithms including geNorm, BestKeeper, Delta Ct, NormFinder, and RefFinder. Our results showed that ACTB, TBP, and HPRT1 were not expressed in exosomes-isolated from studied liver and breast cancer cell lines. The geNorm and BestKeeper algorithms indicated GAPDH and UBC as the most stable candidates. Moreover, Delta Ct and NormFinder algorithms showed YWHAZ as the most stable reference genes. Comprehensive ranking calculated by the RefFinder algorithm also pointed out GAPDH, YWHAZ, and UBC as the first three stable reference genes. Taken together, this study validated the common reference genes stability in exosomal mRNA derived from liver and breast cancer cell lines for the first time. We believe that this study would be the first step in finding more stable reference genes in exosomes that triggers more accurate detection of exosomal biomarkers.
Asunto(s)
Perfilación de la Expresión Génica/métodos , Genes Esenciales/genética , Estabilidad del ARN/genética , Proteínas 14-3-3/genética , Algoritmos , Mama/patología , Neoplasias de la Mama/genética , Línea Celular , Exosomas/genética , Femenino , Expresión Génica/genética , Gliceraldehído-3-Fosfato Deshidrogenasa (Fosforilante)/genética , Humanos , Hígado/patología , Neoplasias Hepáticas/genética , Estabilidad del ARN/fisiología , ARN Mensajero/genética , ARN Mensajero/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Estándares de Referencia , Ubiquitina C/genéticaRESUMEN
Crosstalk between H2B ubiquitylation (H2Bub) and H3 K4 methylation plays important roles in coordinating functions of diverse cofactors during transcription activation. The underlying mechanism for this trans-tail signaling pathway is poorly defined in higher eukaryotes. Here, we show the following: (1) ASH2L in the MLL complex is essential for H2Bub-dependent H3 K4 methylation. Deleting or mutating K99 of the N-terminal winged helix (WH) motif in ASH2L abrogates H2Bub-dependent regulation. (2) Crosstalk can occur in trans and does not require ubiquitin to be on nucleosomes or histones to exert regulatory effects. (3) trans-regulation by ubiquitin promotes MLL activity for all three methylation states. (4) MLL3, an MLL homolog, does not respond to H2Bub, highlighting regulatory specificity for MLL family histone methyltransferases. Altogether, our results potentially expand the classic histone crosstalk to nonhistone proteins, which broadens the scope of chromatin regulation by ubiquitylation signaling.
Asunto(s)
Proteínas de Unión al ADN/química , N-Metiltransferasa de Histona-Lisina/química , Histonas/química , Proteína de la Leucemia Mieloide-Linfoide/química , Proteínas Nucleares/química , Factores de Transcripción/química , Ubiquitinación , Secuencias de Aminoácidos , Sustitución de Aminoácidos , Animales , Proteínas de Unión al ADN/genética , Estabilidad de Enzimas , Expresión Génica , Células HeLa , Histona Metiltransferasas , Histonas/fisiología , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Metilación , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/genética , Nucleosomas , Dominios y Motivos de Interacción de Proteínas , Transducción de Señal , Factores de Transcripción/genética , Ubiquitina C/química , Enzimas Ubiquitina-Conjugadoras/química , Xenopus , Proteínas de Xenopus/químicaRESUMEN
Assimilation of heme is mediated by the cell surface protein Shu1 in Schizosaccharomyces pombe. Shu1 undergoes internalization from the cell surface to the vacuole in response to high concentrations of hemin. Here, we have identified cellular components that are involved in mediating vacuolar targeting of Shu1. Cells deficient in heme biosynthesis and lacking the polyubiquitin gene ubi4+ exhibit poor growth in the presence of exogenous hemin as a sole source of heme. Microscopic analyses of hem1Δ shu1Δ ubi4Δ cells expressing a functional HA4 -tagged Shu1 show that Shu1 localizes to the cell surface. Ubiquitinated Nbr1 functions as a receptor for the endosomal sorting complexes required for transport (ESCRT) that delivers cargos to the vacuole. Inactivation of nbr1+ , ESCRT-0 hse1+ or ESCRT-I sst6+ results in hem1Δ cells being unable to use exogenous hemin for the growth. Using lysate preparations from hemin-treated cells, Shu1-Nbr1 and Shu1-Hse1 complexes are detected by coimmunoprecipitation experiments. Further analysis by immunofluorescence microscopy shows that Shu1 is unable to reach vacuoles of hemin-treated cells harboring a deletion for one of the following genes: ubi4+ , nbr1+ , hse1+ and sst6+ . Together, these results reveal that hemin-mediated vacuolar targeting of Shu1 requires Ubi4-dependent ubiquitination, the receptor Nbr1 and the ESCRT proteins Hse1 and Sst6.
Asunto(s)
Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Hemo/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/crecimiento & desarrollo , Complejos de Clasificación Endosomal Requeridos para el Transporte/genética , Proteínas de la Membrana/genética , Transporte de Proteínas/genética , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética , Ubiquitina C/genética , Ubiquitina C/metabolismo , UbiquitinaciónRESUMEN
Ubi4 is a polyubiquitin precursor well characterized in yeasts but unexplored in insect mycopathogens. Here, we report that orthologous Ubi4 plays a core role in ubiquitin- and asexual lifestyle-required cellular events in Beauveria bassiana. Deletion of ubi4 led to abolished ubiquitin accumulation, blocked autophagic process, severe defects in conidiation and conidial quality, reduced cell tolerance to oxidative, osmotic, cell wall perturbing and heat-shock stresses, decreased transcript levels of development-activating and antioxidant genes, but light effect on radial growth under normal conditions. The deletion mutant lost insect pathogenicity via normal cuticle infection and was severely compromised in virulence via cuticle-bypassing infection due to a block of dimorphic transition critical for acceleration of host mummification. Proteomic and ubiquitylomic analyses revealed 1081 proteins differentially expressed and 639 lysine residues significantly hyper- or hypo-ubiquitylated in the deletion mutant, including dozens of ubiquitin-activating, conjugating and ligating enzymes, core histones, and many more involved in proteasomes, autophagy-lysosome process and protein degradation. Singular deletions of seven ubiquitin-conjugating enzyme genes exerted differential Ubi4-like effects on conidiation level and conidial traits. These findings uncover an essential role of Ubi4 in ubiquitin transfer cascade and its pleiotropic effects on the in vitro and in vivo asexual cycle of B. bassiana.
Asunto(s)
Beauveria/metabolismo , Beauveria/patogenicidad , Insectos/microbiología , Ubiquitina C/genética , Ubiquitina C/metabolismo , Animales , Beauveria/genética , Pared Celular/metabolismo , Proteínas Fúngicas/genética , Regulación Fúngica de la Expresión Génica/genética , Histonas/metabolismo , Control de Plagas/métodos , Poliubiquitina/genética , Poliubiquitina/metabolismo , Proteómica , Esporas Fúngicas/metabolismo , Estrés Fisiológico/genética , Virulencia/genéticaRESUMEN
Murine bone marrow-derived macrophages (M0) and M1- and M2-polarized macrophages are being widely used as a laboratory model for polarized macrophages related molecular mechanism analysis. Gene expression analysis based on reference gene normalization using RT-qPCR was a powerful way to explore the molecular mechanism. But little is known about reference genes in these cell models. So, the goal of this study was to identify reference genes in these types of macrophages. Candidate reference genes in murine bone marrow-derived and polarized macrophages were selected from microarray data using Limma linear model method and evaluated by determining the stability value using five algorithms: BestKeeper, NormFinder, GeNorm, Delta CT method, and RefFinder. Finally, the selected stable reference genes were validated by testing three important immune and inflammatory genes (NLRP1, IL-1ß, and TNF-α) in the cell lines. Our study has clearly shown that Ubc followed by Eef1a1 and B2m respectively were recognized as the three ideal reference genes for gene expression analysis in murine bone marrow-derived and polarized macrophages. When three reference genes with strong different stability were used for validation, a large variation of a gene expression level of IL-1ß, TNF-α and NLRP1 were obtained which provides clear evidence of the need for careful selection of reference genes for RT-qPCR analysis. Normalization of mRNA expression level with Ubc rather than Actb or Gusb by qPCR in macrophages and polarized macrophages is required to ensure the accuracy of the qPCR analysis.
Asunto(s)
Perfilación de la Expresión Génica/normas , Macrófagos/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Algoritmos , Animales , Línea Celular , Expresión Génica/genética , Perfilación de la Expresión Génica/métodos , Macrófagos/fisiología , Ratones , Ratones Endogámicos C57BL , Análisis por Micromatrices/métodos , Factor 1 de Elongación Peptídica/genética , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Estándares de Referencia , Programas Informáticos , Ubiquitina C/genéticaRESUMEN
We studied the influence of magnetite nanoparticles (FeOâ¢Fe2O3) and quantum dots (CdSe/ZnS coated with mercaptopropionic acid) on the expression of 5 common reference genes (BA, B2M, PPIA, UBC, and YWHAZ) in peripheral blood cells from 20 volunteers by reverse transcription PCR method. The stability of the expression of reference genes varied depending of the cells type and chemical structure of nanoparticles. The level of YWHAZ mRNA after exposure by nanoparticles demonstrated highest stability in lymphocytes, neutrophils, and monocytes. Stability of YWHAZ expression was confirmed by Western blotting. Our findings suggest that YWHAZ is the most suitable as the reference gene.
Asunto(s)
Proteínas 14-3-3/genética , Regulación de la Expresión Génica/efectos de los fármacos , Leucocitos Mononucleares/efectos de los fármacos , Nanopartículas de Magnetita/química , Reacción en Cadena de la Polimerasa/normas , Puntos Cuánticos/química , Proteínas 14-3-3/metabolismo , Ácido 3-Mercaptopropiónico/química , Actinas/genética , Actinas/metabolismo , Compuestos de Cadmio/farmacología , Compuestos Férricos/farmacología , Humanos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/metabolismo , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Cultivo Primario de Células , Estándares de Referencia , Compuestos de Selenio/farmacología , Sulfuros/farmacología , Ubiquitina C/genética , Ubiquitina C/metabolismo , Compuestos de Zinc/farmacología , Microglobulina beta-2/genética , Microglobulina beta-2/metabolismoRESUMEN
Stability of many proteins requires zinc. Zinc deficiency disrupts their folding, and the ubiquitin-proteasome system may help manage this stress. In Saccharomyces cerevisiae, UBI4 encodes five tandem ubiquitin monomers and is essential for growth in zinc-deficient conditions. Although UBI4 is only one of four ubiquitin-encoding genes in the genome, a dramatic decrease in ubiquitin was observed in zinc-deficient ubi4Δ cells. The three other ubiquitin genes were strongly repressed under these conditions, contributing to the decline in ubiquitin. In a screen for ubi4Δ suppressors, a hypomorphic allele of the RPT2 proteasome regulatory subunit gene (rpt2(E301K)) suppressed the ubi4Δ growth defect. The rpt2(E301K) mutation also increased ubiquitin accumulation in zinc-deficient cells, and by using a ubiquitin-independent proteasome substrate we found that proteasome activity was reduced. These results suggested that increased ubiquitin supply in suppressed ubi4Δ cells was a consequence of more efficient ubiquitin release and recycling during proteasome degradation. Degradation of a ubiquitin-dependent substrate was restored by the rpt2(E301K) mutation, indicating that ubiquitination is rate-limiting in this process. The UBI4 gene was induced â¼5-fold in low zinc and is regulated by the zinc-responsive Zap1 transcription factor. Surprisingly, Zap1 controls UBI4 by inducing transcription from an intragenic promoter, and the resulting truncated mRNA encodes only two of the five ubiquitin repeats. Expression of a short transcript alone complemented the ubi4Δ mutation, indicating that it is efficiently translated. Loss of Zap1-dependent UBI4 expression caused a growth defect in zinc-deficient conditions. Thus, the intragenic UBI4 promoter is critical to preventing ubiquitin deficiency in zinc-deficient cells.
Asunto(s)
Regulación Fúngica de la Expresión Génica/fisiología , Regiones Promotoras Genéticas/fisiología , Proteínas de Saccharomyces cerevisiae/biosíntesis , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Factores de Transcripción/metabolismo , Activación Transcripcional/fisiología , Ubiquitina C/biosíntesis , Zinc/metabolismo , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Factores de Transcripción/genética , Ubiquitina C/genéticaRESUMEN
The polyubiquitin genes Ubb and Ubc are upregulated under oxidative stress induced by arsenite [As(III)]. However, the role of ubiquitin (Ub) under As(III) exposure is not known in detail. In a previous study, we showed that the reduced viability observed in Ubc-/- mouse embryonic fibroblasts under As(III) exposure was not due to dysregulation of the Nrf2-Keap1 pathway, which prompted us to investigate another NFE2 family protein, nuclear factor erythroid 2-related factor 1 (Nrf1). In this study, we found that Ub deficiency due to Ubc knockdown in N2a cells reduced cell viability and proteasome activity under As(III) exposure. Furthermore, mRNA levels of the proteasome subunit Psma1 were also reduced. In addition, Ub deficiency led to the nuclear accumulation of the p65 isoform of Nrf1 under As(III) exposure. Interestingly, the overexpression of p65-Nrf1 recapitulated the phenotypes of Ub-deficient N2a cells under As(III) exposure. On the other hand, Nrf1 knockdown suppressed the death of Ub-deficient N2a cells upon exposure to As(III). Therefore, the levels of p65-Nrf1 may play an important role in the maintenance of cell viability under oxidative stress induced by As(III).
Asunto(s)
Arsenitos/toxicidad , Factor Nuclear 1 de Respiración/metabolismo , Estrés Oxidativo/efectos de los fármacos , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina/metabolismo , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Ratones , Células 3T3 NIH , Factor Nuclear 1 de Respiración/genética , Complejo de la Endopetidasa Proteasomal/genética , Ubiquitina/genética , Ubiquitina C/genética , Ubiquitina C/metabolismoRESUMEN
Lentiviral vectors almost universally use heterologous internal promoters to express transgenes. One of the most commonly used promoter fragments is a 1.2-kb sequence from the human ubiquitin C (UBC) gene, encompassing the promoter, some enhancers, first exon, first intron and a small part of the second exon of UBC. Because splicing can occur after transcription of the vector genome during vector production, we investigated whether the intron within the UBC promoter fragment is faithfully transmitted to target cells. Genetic analysis revealed that more than 80% of proviral forms lack the intron of the UBC promoter. The human elongation factor 1 alpha (EEF1A1) promoter fragment intron was not lost during lentiviral packaging, and this difference between the UBC and EEF1A1 promoter introns was conferred by promoter exonic sequences. UBC promoter intron loss caused a 4-fold reduction in transgene expression. Movement of the expression cassette to the opposite strand prevented intron loss and restored full expression. This increase in expression was mostly due to non-classical enhancer activity within the intron, and movement of putative intronic enhancer sequences to multiple promoter-proximal sites actually repressed expression. Reversal of the UBC promoter also prevented intron loss and restored full expression in bidirectional lentiviral vectors.
Asunto(s)
Vectores Genéticos , Intrones , Lentivirus/genética , Regiones Promotoras Genéticas , Ubiquitina C/genética , Elementos de Facilitación Genéticos , Exones , Expresión Génica , Células HEK293 , Humanos , Células K562 , Factor 1 de Elongación Peptídica/genética , Empalme del ARNRESUMEN
STUDY DESIGN: Proteomic and 16S rDNA analysis of disc tissues obtained in vivo. OBJECTIVE: To address the controversy of infection as an aetiology for disc disorders through protein profiling. There is raging controversy over the presence of bacteria in human lumbar discs in vivo, and if they represent contamination or infection. Proteomics can provide valuable insight by identifying proteins signifying bacterial presence and, also host defence response proteins (HDRPs), which will confirm infection. METHODS: 22 discs (15-disc herniations (DH), 5-degenerate (DD), 2-normal in MRI (NM) were harvested intraoperatively and immediately snap frozen. Samples were pooled into three groups and proteins extracted were analysed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Post identification, data analysis was performed using Uniprotdb, Pantherdb, Proteome discoverer and STRING network. Authentication for bacterial presence was performed by PCR amplification of 16S rDNA. RESULTS: LC-MS/MS analysis using Orbitrap showed 1103 proteins in DH group, compared to 394 in NM and 564 in DD. 73 bacterial specific proteins were identified (56 specific for Propionibacterium acnes; 17 for Staphylococcus epidermidis). In addition, 67 infection-specific HDRPs, unique or upregulated, such as Defensin, Lysozyme, Dermcidin, Cathepsin-G, Prolactin-Induced Protein, and Phospholipase-A2, were identified confirming presence of infection. Species-specific primers for P. acnes exhibited amplicons at 946 bp (16S rDNA) and 515 bp (Lipase) confirming presence of P. acnes in both NM discs, 11 of 15 DH discs, and all five DD discs. Bioinformatic search for protein-protein interactions (STRING) documented 169 proteins with close interactions (protein clustering co-efficient 0.7) between host response and degenerative proteins implying that infection may initiate degradation through Ubiquitin C. CONCLUSION: Our study demonstrates bacterial specific proteins and host defence proteins to infection which strengthen the hypothesis of infection as a possible initiator of disc disease. These results can lead to a paradigm shift in our understanding and management of disc disorders.
Asunto(s)
Degeneración del Disco Intervertebral/microbiología , Desplazamiento del Disco Intervertebral/microbiología , Proteómica , Adulto , Anciano , Femenino , Infecciones por Bacterias Grampositivas/microbiología , Humanos , Masculino , Persona de Mediana Edad , Propionibacterium acnes/genética , Propionibacterium acnes/aislamiento & purificación , ARN Ribosómico 16S/metabolismo , Ubiquitina C/metabolismo , Adulto JovenRESUMEN
The ligation of peptide hydrazides at a Gly site carrying a removal auxiliary was found to be an efficient process. This technology was successfully used for the synthesis of ubiquitin C-terminal conjugates. Recombinant Ub(1-75)-NHNH2 was prepared through the hydrozinolysis of the Ub(1-75)-intein fusion protein. It was ligated with a glycine derivative modified with an acid-sensitive thiol auxiliary. The final acid treatment produced the desired bioactive ubiquitin conjugates in practical quantities. Thus, the method described here extends the protocols of expressed protein ligation.
Asunto(s)
Técnicas de Química Sintética/métodos , Cumarinas/química , Ubiquitina C/síntesis química , Electroforesis en Gel de Poliacrilamida , Estructura Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Ubiquitina C/químicaRESUMEN
We have previously demonstrated that disruption of polyubiquitin gene Ubc leads to mid-gestation embryonic lethality most likely due to a defect in fetal liver development, which can be partially rescued by ectopic expression of Ub. In a previous study, we assessed the cause of embryonic lethality with respect to the fetal liver hematopoietic system. We confirmed that Ubc(-/-) embryonic lethality could not be attributed to impaired function of hematopoietic stem cells, which raises the question of whether or not FLECs such as hepatocytes and bile duct cells, the most abundant cell types in the liver, are affected by disruption of Ubc and contribute to embryonic lethality. To answer this, we isolated FLCs from E13.5 embryos and cultured them in vitro. We found that proliferation capacity of Ubc(-/-) cells was significantly reduced compared to that of control cells, especially during the early culture period, however we did not observe the increased number of apoptotic cells. Furthermore, levels of Ub conjugate, but not free Ub, decreased upon disruption of Ubc expression in FLCs, and this could not be compensated for by upregulation of other poly- or mono-ubiquitin genes. Intriguingly, the highest Ubc expression levels throughout the entire culture period were observed in bipotent FLEPCs. Hepatocytes and bipotent FLEPCs were most affected by disruption of Ubc, resulting in defective proliferation as well as reduced cell numbers in vitro. These results suggest that defective proliferation of these cell types may contribute to severe reduction of fetal liver size and potentially mid-gestation lethality of Ubc(-/-) embryos.
Asunto(s)
Células Madre Embrionarias/patología , Hepatocitos/patología , Hígado/embriología , Células Madre Multipotentes/patología , Ubiquitina C/deficiencia , Ubiquitina C/genética , Animales , Conductos Biliares Intrahepáticos/citología , Conductos Biliares Intrahepáticos/embriología , Conductos Biliares Intrahepáticos/metabolismo , Proliferación Celular , Células Cultivadas , Células Madre Embrionarias/metabolismo , Células Epiteliales/metabolismo , Células Epiteliales/patología , Hepatocitos/metabolismo , Queratina-19/metabolismo , Hígado/metabolismo , Hígado/patología , Ratones , Ratones Noqueados , Células Madre Multipotentes/metabolismo , Tamaño de los Órganos/genética , Tamaño de los Órganos/fisiología , alfa-Fetoproteínas/metabolismoRESUMEN
Erythropoietin (EPO), a glycoprotein hormone that regulates the production of erythrocytes in the human body, is of clinical importance in the treatment of anemia. Low expression levels of this recombinant hormone and time-consuming screening methods have made its commercial production expensive. Cloning of human EPO gene in a shuttle vector pUB6/V5-HisB driven by human ubiquitin C promoter and its transfection in CHO K1 cell lines by electroporation resulted in a moderate level of EPO expression. The limiting-dilution screening method required several months to obtain high expression stable transfectants but needed only short duration for selection in contrast to the present screening strategy. The supernatants of stably transfected cells were found to be biologically active by in vitro erythroid cluster forming activity.
Asunto(s)
Eritropoyetina/biosíntesis , Proteínas Recombinantes de Fusión/metabolismo , Transfección/métodos , Ubiquitina C/genética , Animales , Western Blotting , Células CHO , Cricetinae , Cricetulus , Resistencia a Medicamentos , Células Eritroides/citología , Células Eritroides/efectos de los fármacos , Eritropoyetina/genética , Eritropoyetina/metabolismo , Eritropoyetina/farmacología , Humanos , Ratones , Nucleósidos , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/farmacología , Células Madre/citología , Células Madre/efectos de los fármacos , Células Madre/fisiologíaRESUMEN
Deubiquitinating enzyme (DUB) abnormalities are associated with many diseases. Previous attempts have been made to introduce various chemical groups such as alkynes, unsaturated olefins and alkyl halides to the C-terminus of ubiquitin (Ub) to capture the active-site cysteine residue in DUBs for structural and biochemical studies. Here, we find that a Ub C-terminal acyl azide can capture DUBs, thereby forming thioester bonds in buffers and cell lysates. This finding not only makes ubiquitin acyl azide a chemical probe for capturing DUBs, but also extends the utility of azide groups in biological applications.
Asunto(s)
Azidas , Ubiquitina C , Ubiquitina/química , Dominio Catalítico , UbiquitinaciónRESUMEN
Each tRNA is aminoacylated (charged) with a genetic codon-specific amino acid. It remains unclear what factors are associated with tRNA charging and how tRNA charging is maintained. By using the individual tRNA acylation PCR method, we found that the charging ratio of tRNAGln (CUG) reflects cellular glutamine level. When uncharged tRNAGln (CUG) increased under amino acid starvation, the kinase GCN2, which is a key stimulator of the integrated stress response, was activated. Activation of GCN2 led to the upregulation of ubiquitin C (UBC) expression. Upregulated UBC, in turn, suppressed the further reduction in tRNAGln (CUG) charging levels. Thus, tRNA charging is sensitive to intracellular nutrient status and is an important initiator of intracellular signaling.
Asunto(s)
Aminoácidos , Proteínas de Saccharomyces cerevisiae , Aminoácidos/metabolismo , Glutamina/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , ARN de Transferencia de Glutamina/metabolismo , Ubiquitina C/genética , Ubiquitina C/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Regulación hacia ArribaRESUMEN
A nasopharyngeal swab (NPS) is the most frequently collected sample type when molecular diagnosis of respiratory viruses, including SARS CoV-2, is required. An optimal collection technique would provide sufficient sample quality for the diagnostic process and would minimize the discomfort felt by the patient. This study compares a simplified NPS collection procedure with only one rotation of the swab to a more standard procedure with five rotations. Swabs were collected from 76 healthy volunteers by the same healthcare professional on 2 consecutive days at a similar hour to minimize variability. The number of Ubiquitin C copy number per sample was measured by real-time quantitative PCR and patient discomfort was assessed by questionnaire. No statistically significant difference (p = 0.15) was observed in the Ubiquitin C copy number per sample between a NPS collected with one rotation (5.2 ± 0.6 log UBC number copies/sample) or five rotations (5.3 ± 0.5 log UBC number copies/sample). However, a statistically significant difference was observed in discomfort between these two procedures, the second being much more uncomfortable. Additional analysis of the results showed a weak correlation between discomfort and the number of human cells recovered (Spearman's rho = 0.202) and greater discomfort in younger people. The results of this study show that a NPS collected with one slow rotation has the same quality as a NPS collected with five rotations. However, the collection time is shorter and, most importantly, less unpleasant for patients.
Asunto(s)
COVID-19 , Humanos , Ubiquitina C , Nasofaringe , SARS-CoV-2 , Manejo de Especímenes/métodosRESUMEN
Previously, we demonstrated that disruption of polyubiquitin gene Ubb leads to hypothalamic neurodegeneration and metabolic abnormalities associated with hypothalamic dysfunction. However, we cannot exclude the possibility that defects in other brain regions where Ubb is highly expressed may also contribute to the phenotypes exhibited by Ubb(-/-) mice. Upon searching for such brain regions, we identified a region in the brainstem called the locus coeruleus where both polyubiquitin genes Ubb and Ubc were highly expressed. In contrast to other brain regions, Ubc was significantly upregulated in the locus coeruleus of Ubb(-/-) mice presumably to compensate for loss of Ubb, and this upregulation was sufficient to maintain levels of free Ub, but not total Ub, in the locus coeruleus. However, in the hypothalamus of Ubb(-/-) mice, both free and total Ub levels significantly decreased. This discrepancy resulted in completely different phenotypic outcomes between the two different brain regions. While we have reported dysfunction and degeneration of hypothalamic neurons in adult Ubb(-/-) mice, there were no signs of functional impairment or degeneration in the locus coeruleus neurons, suggesting that the maintenance of free Ub above threshold levels could be an important mechanism for neuronal protection. Accordingly, we propose that, upon stress induced by disruption of Ubb, neuronal vulnerability may be determined based on the ability of neurons or neighboring cells to maintain free Ub levels for the protection of neuronal function and survival.
Asunto(s)
Locus Coeruleus/metabolismo , Degeneración Nerviosa/metabolismo , Neuronas/metabolismo , Poliubiquitina/metabolismo , Ubiquitina/metabolismo , Animales , Supervivencia Celular , Locus Coeruleus/anomalías , Locus Coeruleus/patología , Ratones , Ratones Mutantes , Degeneración Nerviosa/patología , Neuronas/patología , Poliubiquitina/genética , Ubiquitina/genética , Ubiquitina C/genética , Ubiquitina C/metabolismoRESUMEN
In general, for real-time quantitative polymerase chain reaction (qPCR), normalization strategies use a reference gene as a control and to avoid the introduction of experimental errors expression of this gene should not vary in response to changing conditions. However, the expression of many reference genes has been reported to vary considerably and, without appropriate normalization, the expression profile of a target gene can be misinterpreted. In this study, the expression levels of seven commonly used reference genes (ACT, GAPDH, 28srRNA, RPL3, α-tubulin, UBC, and TBP) were detected at different development time points and in response to treatment with 20-hydroxyecdysone (20E) and with rutin. The expression stability was analyzed using geNorm and NormFinder software. Significant variations were found among normal tissues and between experimentally treated tissues. The dual spike-in strategy also revealed significant variations of the expression levels of the reference genes among normal tissues and between experimentally treated tissues. Glutathione-S-transferase sigma 1 (GSTs1), which has a high expression level in fat body and is related to the mechanism of resistance, was used as a target gene to validate the feasibility and difference of these two approaches.