Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 65
Filtrar
1.
Int J Biol Macromol ; 274(Pt 1): 133163, 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38878927

RESUMEN

Polycomb groups (PcGs) are transcriptional repressors, formed by a complex of several proteins, involved in multicellular development and cancer epigenetics. One of these proteins is the E3 ubiquitin-protein ligase RING1 (or RING1B), associated with the regulation of transcriptional repression and responsible for monoubiquitylation of the histone H2A. On the other hand, PADI4 is one of the human isoforms of a family of enzymes implicated in the conversion of arginine to citrulline, and it is also involved in the development of glioblastoma, among other types of cancers. In this work, we showed the association of PADI4 and RING1B in the nucleus and cytosol in several cancer cell lines by using immunofluorescence and proximity ligation assays. Furthermore, we demonstrated that binding was hampered in the presence of GSK484, an enzymatic PADI4 inhibitor, suggesting that RING1B could bind to the active site of PADI4, as confirmed by protein-protein docking simulations. In vitro and in silico findings showed that binding to PADI4 occurred for the isolated fragments corresponding to both the N-terminal (residues 1-221) and C-terminal (residues 228-336) regions of RING1B. Binding to PADI4 was also hampered by GSK484, as shown by isothermal titration calorimetry (ITC) experiments for the sole N-terminal region, and by both NMR and ITC for the C-terminal one. The dissociation constants between PADI4 and any of the two isolated RING1B fragments were in the low micromolar range (~2-10 µM), as measured by fluorescence and ITC. The interaction between RING1B and PADI4 might imply citrullination of the former, leading to several biological consequences, as well as being of potential therapeutic relevance for improving cancer treatment with the generation of new antigens.

2.
Biomolecules ; 14(5)2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38785968

RESUMEN

Plakophilin 1 (PKP1), a member of the p120ctn subfamily of the armadillo (ARM)-repeat-containing proteins, is an important structural component of cell-cell adhesion scaffolds although it can also be ubiquitously found in the cytoplasm and the nucleus. RYBP (RING 1A and YY1 binding protein) is a multifunctional intrinsically disordered protein (IDP) best described as a transcriptional regulator. Both proteins are involved in the development and metastasis of several types of tumors. We studied the binding of the armadillo domain of PKP1 (ARM-PKP1) with RYBP by using in cellulo methods, namely immunofluorescence (IF) and proximity ligation assay (PLA), and in vitro biophysical techniques, namely fluorescence, far-ultraviolet (far-UV) circular dichroism (CD), and isothermal titration calorimetry (ITC). We also characterized the binding of the two proteins by using in silico experiments. Our results showed that there was binding in tumor and non-tumoral cell lines. Binding in vitro between the two proteins was also monitored and found to occur with a dissociation constant in the low micromolar range (~10 µM). Finally, in silico experiments provided additional information on the possible structure of the binding complex, especially on the binding ARM-PKP1 hot-spot. Our findings suggest that RYBP might be a rescuer of the high expression of PKP1 in tumors, where it could decrease the epithelial-mesenchymal transition in some cancer cells.


Asunto(s)
Proteínas Intrínsecamente Desordenadas , Placofilinas , Unión Proteica , Humanos , Placofilinas/metabolismo , Placofilinas/genética , Placofilinas/química , Proteínas Intrínsecamente Desordenadas/metabolismo , Proteínas Intrínsecamente Desordenadas/química , Proteínas Intrínsecamente Desordenadas/genética , Proteínas Represoras/metabolismo , Proteínas Represoras/química , Proteínas Represoras/genética , Proteínas del Dominio Armadillo/metabolismo , Proteínas del Dominio Armadillo/química , Proteínas del Dominio Armadillo/genética , Dominios Proteicos , Dicroismo Circular
3.
Biosensors (Basel) ; 14(4)2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38667166

RESUMEN

Heart failure (HF) is a clinical entity included in cardiovascular diseases affecting millions of people worldwide, being a leading cause of hospitalization of older adults, and therefore imposing a substantial economic burden on healthcare systems. HF is characterized by dyspnea, fatigue, and edema associated with elevated blood levels of natriuretic peptides, such as N Terminal pro-B-type Natriuretic Peptide (NT-proBNP), for which there is a high demand for point of care testing (POCT) devices. Optical fiber (OF) biosensors offer a promising solution, capable of real-time detection, quantification, and monitoring of NT-proBNP concentrations in serum, saliva, or urine. In this study, immunosensors based on plasmonic uncladded OF tips were developed using OF with different core diameters (200 and 600 µm). The tips were characterized to bulk refractive index (RI), anddetection tests were conducted with NT-proBNP concentrations varying from 0.01 to 100 ng/mL. The 200 µm sensors showed an average total variation of 3.6 ± 2.5 mRIU, an average sensitivity of 50.5 mRIU/ng·mL-1, and a limit of detection (LOD) of 0.15 ng/mL, while the 600 µm sensors had a response of 6.1 ± 4.2 mRIU, a sensitivity of 102.8 mRIU/ng·mL-1, and an LOD of 0.11 ng/mL. Control tests were performed using interferents such as uric acid, glucose, and creatinine. The results show the potential of these sensors for their use in biological fluids.


Asunto(s)
Técnicas Biosensibles , Péptido Natriurético Encefálico , Fibras Ópticas , Fragmentos de Péptidos , Péptido Natriurético Encefálico/sangre , Humanos , Fragmentos de Péptidos/sangre , Fragmentos de Péptidos/análisis , Insuficiencia Cardíaca/diagnóstico , Límite de Detección
4.
Cell Death Dis ; 14(8): 501, 2023 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-37542070

RESUMEN

Gonadal sex determination and differentiation are controlled by somatic support cells of testes (Sertoli cells) and ovaries (granulosa cells). In testes, the epigenetic mechanism that maintains chromatin states responsible for suppressing female sexual differentiation remains unclear. Here, we show that Polycomb repressive complex 1 (PRC1) suppresses a female gene regulatory network in postnatal Sertoli cells. We genetically disrupted PRC1 function in embryonic Sertoli cells after sex determination, and we found that PRC1-depleted postnatal Sertoli cells exhibited defective proliferation and cell death, leading to the degeneration of adult testes. In adult Sertoli cells, PRC1 suppressed specific genes required for granulosa cells, thereby inactivating the female gene regulatory network. Chromatin regions associated with female-specific genes were marked by Polycomb-mediated repressive modifications: PRC1-mediated H2AK119ub and PRC2-mediated H3K27me3. Taken together, this study identifies a critical Polycomb-based mechanism that suppresses ovarian differentiation and maintains Sertoli cell fate in adult testes.


Asunto(s)
Histonas , Complejo Represivo Polycomb 1 , Femenino , Masculino , Humanos , Complejo Represivo Polycomb 1/genética , Complejo Represivo Polycomb 1/metabolismo , Histonas/genética , Histonas/metabolismo , Testículo/metabolismo , Redes Reguladoras de Genes , Complejo Represivo Polycomb 2/genética , Complejo Represivo Polycomb 2/metabolismo , Cromatina , Proteínas del Grupo Polycomb/genética , Proteínas del Grupo Polycomb/metabolismo , Diferenciación Celular/genética
5.
Int J Biol Macromol ; 246: 125632, 2023 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-37399862

RESUMEN

RYBP (Ring1 and YY 1 binding protein) is a multifunctional, intrinsically disordered protein (IDP), best described as a transcriptional regulator. It exhibits a ubiquitin-binding functionality, binds to other transcription factors, and has a key role during embryonic development. RYBP, which folds upon binding to DNA, has a Zn-finger domain at its N-terminal region. By contrast, PADI4 is a well-folded protein and it is one the human isoforms of a family of enzymes implicated in the conversion of arginine to citrulline. As both proteins intervene in signaling pathways related to cancer development and are found in the same localizations within the cell, we hypothesized they may interact. We observed their association in the nucleus and cytosol in several cancer cell lines, by using immunofluorescence (IF) and proximity ligation assays (PLAs). Binding also occurred in vitro, as measured by isothermal titration calorimetry (ITC) and fluorescence, with a low micromolar affinity (~1 µM). AlphaFold2-multimer (AF2) results indicate that PADI4's catalytic domain interacts with the Arg53 of RYBP docking into its active site. As RYBP sensitizes cells to PARP (Poly (ADP-ribose) polymerase) inhibitors, we applied them in combination with an enzymatic inhibitor of PADI4 observing a change in cell proliferation, and the hampering of the interaction of both proteins. This study unveils for the first time the possible citrullination of an IDP, and suggests that this new interaction, whether it involves or not citrullination of RYBP, might have implications in cancer development and progression.


Asunto(s)
Neoplasias , Factores de Transcripción , Humanos , Factores de Transcripción/genética , Línea Celular , Neoplasias/genética , Epigénesis Genética , Proteínas Represoras/genética
6.
Nat Commun ; 13(1): 4510, 2022 08 10.
Artículo en Inglés | MEDLINE | ID: mdl-35948547

RESUMEN

The ovarian reserve defines the female reproductive lifespan, which in humans spans decades due to robust maintenance of meiotic arrest in oocytes residing in primordial follicles. Epigenetic reprogramming, including DNA demethylation, accompanies meiotic entry, but the chromatin changes that underpin the generation and preservation of ovarian reserves are poorly defined. We report that the Polycomb Repressive Complex 1 (PRC1) establishes repressive chromatin states in perinatal mouse oocytes that directly suppress the gene expression program of meiotic prophase-I and thereby enable the transition to dictyate arrest. PRC1 dysfuction causes depletion of the ovarian reserve and leads to premature ovarian failure. Our study demonstrates a fundamental role for PRC1-mediated gene silencing in female reproductive lifespan, and reveals a critical window of epigenetic programming required to establish ovarian reserve.


Asunto(s)
Reserva Ovárica , Complejo Represivo Polycomb 1 , Animales , Proteínas de Ciclo Celular/metabolismo , Cromatina/genética , Femenino , Silenciador del Gen , Humanos , Meiosis/genética , Ratones , Reserva Ovárica/genética , Complejo Represivo Polycomb 1/metabolismo
7.
Biomed Opt Express ; 13(6): 3259-3274, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35781957

RESUMEN

Measuring cortisol levels as a stress biomarker is essential in many medical conditions associated with a high risk of metabolic syndromes such as anxiety and cardiovascular diseases, among others. One technology that has a growing interest in recent years is fiber optic biosensors that enable ultrasensitive cortisol detection. Such interest is allied with progress being achieved in basic interrogation, accuracy improvements, and novel applications. The development of improved cortisol monitoring, with a simplified manufacturing process, high reproducibility, and low cost, are challenges that these sensing mechanisms still face, and for which solutions are still needed. In this paper, a comprehensive characterization of a D-shaped fiber optic immunosensor for cortisol detection based on surface plasmon resonance (SPR) enabled by gold coating is reported. Specifically, the sensor instrumentation and fabrication processes are discussed in detail, and a simulation with its complete mathematical formalism is also presented. Moreover, experimental cortisol detection tests were performed for a detection range of 0.01 to 100 ng/mL, attaining a logarithmic sensitivity of 0.65 ± 0.02 nm/log(ng/mL) with a limit of detection (LOD) of 1.46 ng/mL. Additionally, an investigation of signal processing is also discussed, with the main issues addressed in order to highlight the best way to extract the sensing information from the spectra measured with a D-shaped sensor.

8.
Sensors (Basel) ; 22(6)2022 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-35336312

RESUMEN

Optical fiber technology has rapidly progressed over the years, providing valuable benefits for biosensing purposes such as sensor miniaturization and the possibility for remote and real-time monitoring. In particular, tilted fiber Bragg gratings (TFBGs) are extremely sensitive to refractive index variations taking place on their surface. The present work comprises a case-study on the impact of different methods of analysis applied to decode spectral variations of bare and plasmonic TFBGs during the detection of N-terminal B-type natriuretic peptide (NT-proBNP), a heart failure biomarker, namely by following the most sensitive mode, peaks of the spectral envelopes, and the envelopes' crossing point and area. Tracking the lower envelope resulted in the lowest limits of detection (LOD) for bare and plasmonic TFBGs, namely, 0.75 ng/mL and 0.19 ng/mL, respectively. This work demonstrates the importance of the analysis method on the outcome results, which is crucial to attain the most reliable and sensitive method with lower LOD sensors. Furthermore, it makes the scientific community aware to take careful attention when comparing the performance of different biosensors in which different analysis methods were used.


Asunto(s)
Técnicas Biosensibles , Insuficiencia Cardíaca , Técnicas Biosensibles/métodos , Insuficiencia Cardíaca/diagnóstico , Humanos , Límite de Detección , Fibras Ópticas , Refractometría
9.
Biosensors (Basel) ; 11(9)2021 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-34562895

RESUMEN

The evolution of optical fiber technology has revolutionized a variety of fields, from optical transmission to environmental monitoring and biomedicine, given their unique properties and versatility. For biosensing purposes, the light guided in the fiber core is exposed to the surrounding media where the analytes of interest are detected by different techniques, according to the optical fiber configuration and biofunctionalization strategy employed. These configurations differ in manufacturing complexity, cost and overall performance. The biofunctionalization strategies can be carried out directly on bare fibers or on coated fibers. The former relies on interactions between the evanescent wave (EW) of the fiber and the analyte of interest, whereas the latter can comprise plasmonic methods such as surface plasmon resonance (SPR) and localized SPR (LSPR), both originating from the interaction between light and metal surface electrons. This review presents the basics of optical fiber immunosensors for a broad audience as well as the more recent research trends on the topic. Several optical fiber configurations used for biosensing applications are highlighted, namely uncladded, U-shape, D-shape, tapered, end-face reflected, fiber gratings and special optical fibers, alongside practical application examples. Furthermore, EW, SPR, LSPR and biofunctionalization strategies, as well as the most recent advances and applications of immunosensors, are also covered. Finally, the main challenges and an outlook over the future direction of the field is presented.


Asunto(s)
Técnicas Biosensibles , Inmunoensayo , Fibras Ópticas , Metales , Resonancia por Plasmón de Superficie
10.
Epigenomes ; 4(3)2020 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-34968290

RESUMEN

Chromatin regulators of the Polycomb group of genes are well-known by their activities as transcriptional repressors. Characteristically, their presence at genomic sites occurs with specific histone modifications and sometimes high-order chromatin structures correlated with silencing of genes involved in cell differentiation. However, evidence gathered in recent years, on flies and mammals, shows that in addition to these sites, Polycomb products bind to a large number of active regulatory regions. Occupied sites include promoters and also intergenic regions, containing enhancers and super-enhancers. Contrasting with occupancies at repressed targets, characteristic histone modifications are low or undetectable. Functions on active targets are dual, restraining gene expression at some targets while promoting activity at others. Our aim here is to summarize the evidence available and discuss the convenience of broadening the scope of research to include Polycomb functions on active targets.

11.
Epigenomes ; 3(2)2019 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-34968234

RESUMEN

The Polycomb system is made of an evolutionary ancient group of proteins, present throughout plants and animals. Known initially from developmental studies with the fly Drosophila melanogaster, they were associated with stable sustainment of gene repression and maintenance of cell identity. Acting as multiprotein assemblies with an ability to modify chromatin, through chemical additions to histones and organization of topological domains, they have been involved subsequently in control of developmental transitions and in cell homeostasis. Recent work has unveiled an association of Polycomb components with transcriptionally active loci and the promotion of gene expression, in clear contrast with conventional recognition as repressors. Focusing on mammalian models, I review here advances concerning roles in transcriptional control. Among new findings highlighted is the regulation of their catalytic properties, recruiting to targets, and activities in chromatin organization and compartmentalization. The need for a more integrated approach to the study of the Polycomb system, given its fundamental complexity and its adaptation to cell context, is discussed.

12.
Plant Cell Physiol ; 60(3): 575-586, 2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-30476329

RESUMEN

Signals and signaling pathways underlying the symbiosis between legumes and rhizobia have been studied extensively over the past decades. In a previous phosphoproteomic study on the Medicago truncatula-Sinorhizobium meliloti symbiosis, we identified plant proteins that are differentially phosphorylated upon the perception of rhizobial signals, called Nod factors. In this study, we provide experimental evidence that one of these proteins, Early Phosphorylated Protein 1 (EPP1), is required for the initiation of this symbiosis. Upon inoculation with rhizobia, MtEPP1 expression was induced in curled root hairs. Down-regulation of MtEPP1 in M. truncatula roots almost abolished calcium spiking, reduced the expression of essential symbiosis-related genes (MtNIN, MtNF-YB1, MtERN1 and MtENOD40) and strongly decreased nodule development. Phylogenetic analyses revealed that orthologs of MtEPP1 are present in legumes and specifically in plant species able to host arbuscular mycorrhizal fungi, suggesting a possible role in this association too. Short chitin oligomers induced the phosphorylation of MtEPP1 like Nod factors. However, the down-regulation of MtEPP1 affected the colonization of M. truncatula roots by arbuscular mycorrhizal fungi only moderately. Altogether, these findings indicate that MtEPP1 is essential for the establishment of the legume-rhizobia symbiosis but might plays a limited role in the arbuscular mycorrhizal symbiosis.


Asunto(s)
Medicago truncatula/metabolismo , Proteínas de Plantas/metabolismo , Nódulos de las Raíces de las Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Proteínas de Plantas/genética , Nódulos de las Raíces de las Plantas/genética , Simbiosis/genética , Simbiosis/fisiología
13.
Development ; 145(19)2018 10 11.
Artículo en Inglés | MEDLINE | ID: mdl-30190278

RESUMEN

Suppression of Meis genes in the distal limb bud is required for proximal-distal (PD) specification of the forelimb. Polycomb group (PcG) factors play a role in downregulation of retinoic acid (RA)-related signals in the distal forelimb bud, causing Meis repression. It is, however, not known whether downregulation of RA-related signals and PcG-mediated proximal gene repression are functionally linked. Here, we reveal that PcG factors and RA-related signals antagonize each other to polarize Meis2 expression along the PD axis in mouse. Supported by mathematical modeling and simulation, we propose that PcG factors are required to adjust the threshold for RA-related signaling to regulate Meis2 expression. Finally, we show that a variant Polycomb repressive complex 1 (PRC1), incorporating PCGF3 and PCGF5, represses Meis2 expression in the distal limb bud. Taken together, we reveal a previously unknown link between PcG proteins and downregulation of RA-related signals to mediate the phase transition of Meis2 transcriptional status during forelimb patterning.


Asunto(s)
Miembro Anterior/embriología , Proteínas de Homeodominio/metabolismo , Esbozos de los Miembros/metabolismo , Complejo Represivo Polycomb 1/metabolismo , Tretinoina/metabolismo , Animales , Miembro Anterior/metabolismo , Regulación del Desarrollo de la Expresión Génica , Sitios Genéticos , Ratones , Transducción de Señal
14.
Biochem J ; 475(14): 2271-2291, 2018 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-29925531

RESUMEN

NUPR1 is a protumoral multifunctional intrinsically disordered protein (IDP), which is activated during the acute phases of pancreatitis. It interacts with other IDPs such as prothymosin α, as well as with folded proteins such as the C-terminal region of RING1-B (C-RING1B) of the Polycomb complex; in all those interactions, residues around Ala33 and Thr68 (the 'hot-spot' region) of NUPR1 intervene. Its paralogue, NUPR1L, is also expressed in response to DNA damage, it is p53-regulated, and its expression down-regulates that of the NUPR1 gene. In this work, we characterized the conformational preferences of isolated NUPR1L and its possible interactions with the same molecular partners of NUPR1. Our results show that NUPR1L was an oligomeric IDP from pH 2.0 to 12.0, as judged by steady-state fluorescence, circular dichroism (CD), dynamic light scattering, 1D 1H-NMR (nuclear magnetic resonance), and as indicated by structural modelling. However, in contrast with NUPR1, there was evidence of local helical- or turn-like structures; these structures were not rigid, as judged by the lack of sigmoidal behaviour in the chemical and thermal denaturation curves obtained by CD and fluorescence. Interestingly enough, NUPR1L interacted with prothymosin α and C-RING1B, and with a similar affinity to that of NUPR1 (in the low micromolar range). Moreover, NUPR1L hetero-associated with NUPR1 with an affinity of 0.4 µM and interacted with the 'hot-spot' region of NUPR1. Thus, we suggest that the regulation of NUPR1 gene by NUPR1L does not only happen at the DNA level, but it could also involve direct interactions with NUPR1 natural partners.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/química , Proteínas Intrínsecamente Desordenadas/química , Proteínas de Neoplasias/química , Multimerización de Proteína , Proteínas Represoras/química , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Humanos , Proteínas Intrínsecamente Desordenadas/metabolismo , Proteínas de Neoplasias/metabolismo , Resonancia Magnética Nuclear Biomolecular , Unión Proteica , Estructura Cuaternaria de Proteína , Estructura Secundaria de Proteína , Proteínas Represoras/metabolismo
15.
Genes Dev ; 31(16): 1693-1703, 2017 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-28924034

RESUMEN

During spermatogenesis, a large number of germline genes essential for male fertility are coordinately activated. However, it remains unknown how timely activation of this group of germline genes is accomplished. Here we show that Polycomb-repressive complex 1 (PRC1) directs timely activation of germline genes during spermatogenesis. Inactivation of PRC1 in male germ cells results in the gradual loss of a stem cell population and severe differentiation defects, leading to male infertility. In the stem cell population, RNF2, the dominant catalytic subunit of PRC1, activates transcription of Sall4, which codes for a transcription factor essential for subsequent spermatogenic differentiation. Furthermore, RNF2 and SALL4 together occupy transcription start sites of germline genes in the stem cell population. Once differentiation commences, these germline genes are activated to enable the progression of spermatogenesis. Our study identifies a novel mechanism by which Polycomb directs the developmental process by activating a group of lineage-specific genes.


Asunto(s)
Complejo Represivo Polycomb 1/fisiología , Espermatogénesis/genética , Activación Transcripcional , Animales , Línea Celular , Proteínas de Unión al ADN/metabolismo , Epigénesis Genética , Masculino , Ratones , Ratones Transgénicos , Complejo Represivo Polycomb 1/genética , Complejo Represivo Polycomb 1/metabolismo , Espermatogonias/citología , Espermatogonias/metabolismo , Factores de Transcripción/metabolismo , Sitio de Iniciación de la Transcripción , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo
16.
Proc Natl Acad Sci U S A ; 114(31): E6332-E6341, 2017 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-28720707

RESUMEN

Intrinsically disordered proteins (IDPs) are ubiquitous in eukaryotes, and they are often associated with diseases in humans. The protein NUPR1 is a multifunctional IDP involved in chromatin remodeling and in the development and progression of pancreatic cancer; however, the details of such functions are unknown. Polycomb proteins are involved in specific transcriptional cascades and gene silencing. One of the proteins of the Polycomb complex is the Ring finger protein 1 (RING1). RING1 is related to aggressive tumor features in multiple cancer types. In this work we characterized the interaction between NUPR1 and the paralogue RING1B in vitro, in silico, and in cellulo. The interaction occurred through the C-terminal region of RING1B (C-RING1B), with an affinity in the low micromolar range (∼10 µM). The binding region of NUPR1, mapped by NMR, was a hydrophobic polypeptide patch at the 30s region of its sequence, as pinpointed by computational results and site-directed mutagenesis at Ala33. The association between C-RING1B and wild-type NUPR1 also occurred in cellulo as tested by protein ligation assays; this interaction is inhibited by trifluoperazine, a drug known to hamper binding of wild-type NUPR1 with other proteins. Furthermore, the Thr68Gln and Ala33Gln/Thr68Gln mutants had a reduction in the binding toward C-RING1B as shown by in vitro, in silico, and in cellulo studies. This is an example of a well-folded partner of NUPR1, because its other interacting proteins are also unfolded. We hypothesize that NUPR1 plays an active role in chromatin remodeling and carcinogenesis, together with Polycomb proteins.

17.
Exp Hematol ; 48: 12-31, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-28087428

RESUMEN

Hematopoiesis, the process by which blood cells are continuously produced, is one of the best studied differentiation pathways. Hematological diseases are associated with reiterated mutations in genes encoding important gene expression regulators, including chromatin regulators. Among them, the Polycomb group (PcG) of proteins is an essential system of gene silencing involved in the maintenance of cell identities during differentiation. PcG proteins assemble into two major types of Polycomb repressive complexes (PRCs) endowed with distinct histone-tail-modifying activities. PRC1 complexes are histone H2A E3 ubiquitin ligases and PRC2 trimethylates histone H3. Established conceptions about their activities, mostly derived from work in embryonic stem cells, are being modified by new findings in differentiated cells. Here, we focus on PRC1 complexes, reviewing recent evidence on their intricate architecture, the diverse mechanisms of their recruitment to targets, and the different ways in which they engage in transcriptional control. We also discuss hematopoietic PRC1 gain- and loss-of-function mouse strains, including those that model leukemic and lymphoma diseases, in the belief that these genetic analyses provide the ultimate test for molecular mechanisms driving normal hematopoiesis and hematological malignancies.


Asunto(s)
Hematopoyesis , Complejo Represivo Polycomb 1/metabolismo , Animales , Proteínas Portadoras/metabolismo , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Cromatina/genética , Cromatina/metabolismo , Ensamble y Desensamble de Cromatina , Regulación de la Expresión Génica , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/metabolismo , Humanos , Complejo Represivo Polycomb 1/química , Complejo Represivo Polycomb 1/genética , Proteínas del Grupo Polycomb/química , Proteínas del Grupo Polycomb/genética , Proteínas del Grupo Polycomb/metabolismo , Unión Proteica , Activación Transcripcional
18.
Genes Dev ; 30(22): 2475-2485, 2016 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-27913604

RESUMEN

In general, cell fate is determined primarily by transcription factors, followed by epigenetic mechanisms fixing the status. While the importance of transcription factors controlling cell fate has been well characterized, epigenetic regulation of cell fate maintenance remains to be elucidated. Here we provide an obvious fate conversion case, in which the inactivation of polycomb-medicated epigenetic regulation results in conversion of T-lineage progenitors to the B-cell fate. In T-cell-specific Ring1A/B-deficient mice, T-cell development was severely blocked at an immature stage. We found that these developmentally arrested T-cell precursors gave rise to functional B cells upon transfer to immunodeficient mice. We further demonstrated that the arrest was almost completely canceled by additional deletion of Pax5 These results indicate that the maintenance of T-cell fate critically requires epigenetic suppression of the B-lineage gene program.


Asunto(s)
Linfocitos B/citología , Transformación Celular Neoplásica/genética , Epigénesis Genética/genética , Silenciador del Gen , Proteínas del Grupo Polycomb/metabolismo , Linfocitos T/citología , Animales , Linaje de la Célula , Eliminación de Gen , Regulación del Desarrollo de la Expresión Génica , Cadenas Pesadas de Inmunoglobulina/genética , Ratones Endogámicos C57BL , Factor de Transcripción PAX5/genética , Factor de Transcripción PAX5/metabolismo , Complejo Represivo Polycomb 1/genética , Regiones Promotoras Genéticas/genética , Ubiquitina-Proteína Ligasas/genética
19.
Development ; 143(2): 276-85, 2016 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-26674308

RESUMEN

Polycomb group (PcG) proteins play a pivotal role in silencing developmental genes and help to maintain various stem and precursor cells and regulate their differentiation. PcG factors also regulate dynamic and complex regional specification, particularly in mammals, but this activity is mechanistically not well understood. In this study, we focused on proximal-distal (PD) patterning of the mouse forelimb bud to elucidate how PcG factors contribute to a regional specification process that depends on developmental signals. Depletion of the RING1 proteins RING1A (RING1) and RING1B (RNF2), which are essential components of Polycomb repressive complex 1 (PRC1), led to severe defects in forelimb formation along the PD axis. We show that preferential defects in early distal specification in Ring1A/B-deficient forelimb buds accompany failures in the repression of proximal signal circuitry bound by RING1B, including Meis1/2, and the activation of distal signal circuitry in the prospective distal region. Additional deletion of Meis2 induced partial restoration of the distal gene expression and limb formation seen in the Ring1A/B-deficient mice, suggesting a crucial role for RING1-dependent repression of Meis2 and likely also Meis1 for distal specification. We suggest that the RING1-MEIS1/2 axis is regulated by early PD signals and contributes to the initiation or maintenance of the distal signal circuitry.


Asunto(s)
Miembro Anterior/embriología , Proteínas de Homeodominio/metabolismo , Complejo Represivo Polycomb 1/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Inmunoprecipitación de Cromatina , Sistema Enzimático del Citocromo P-450/genética , Sistema Enzimático del Citocromo P-450/metabolismo , Femenino , Regulación del Desarrollo de la Expresión Génica/genética , Regulación del Desarrollo de la Expresión Génica/fisiología , Proteínas de Homeodominio/genética , Hibridación in Situ , Masculino , Ratones , Ratones Mutantes , Complejo Represivo Polycomb 1/genética , Embarazo , Ácido Retinoico 4-Hidroxilasa , Tretinoina/farmacología , Ubiquitina-Proteína Ligasas/genética
20.
Mol Cell Biol ; 36(6): 900-12, 2015 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-26711264

RESUMEN

Polycomb chromatin modifiers regulate hematopoietic pluripotent stem and progenitor cell self-renewal and expansion. Polycomb complex redundancy and biochemical heterogeneity complicate the unraveling of the functional contributions of distinct components. We have studied the hematopoietic activity of RYBP, a direct interactor and proposed modulator of RING1A/RING1B-dependent histone H2A monoubiquitylation (H2AUb). Using a mouse model to conditionally inactivate Rybp in adult hematopoiesis, we have found that RYBP deletion results in a reversion of B-1-to-B-2 B-cell progenitor ratios, i.e., of the innate (predominantly fetal) to acquired (mostly adult) immunity precursors. Increased numbers of B-1 progenitors correlated with a loss of pre-proB cells, the B-2 progenitors. RYBP-deficient stem and progenitor cell populations (LKS) and isolated common lymphoid progenitors (CLP) gave rise to increased numbers of B-1 progenitors in vitro. Rybp inactivation, however, did not result in changes of global H2AUb and did not interact genetically with Ring1A or Ring1B deletions. These results show that a sustained regulation of the B-1-to-B-2 switch is needed throughout adult life and that RYBP plays an important role in keeping B-2 dominance, most likely independently of its Polycomb affiliation.


Asunto(s)
Linfocitos B/citología , Hematopoyesis , Células Madre Hematopoyéticas/citología , Proteínas Represoras/metabolismo , Animales , Linfocitos B/metabolismo , Línea Celular , Linaje de la Célula , Células Cultivadas , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Eliminación de Gen , Células Madre Hematopoyéticas/metabolismo , Ratones , Complejo Represivo Polycomb 1/genética , Complejo Represivo Polycomb 1/metabolismo , Proteínas Represoras/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA