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1.
Mol Cell ; 82(14): 2557-2570.e7, 2022 07 21.
Artículo en Inglés | MEDLINE | ID: mdl-35594857

RESUMEN

Antigen presentation by the human leukocyte antigen (HLA) on the cell surface is critical for the transduction of the immune signal toward cytotoxic T lymphocytes. DNA damage upregulates HLA class I presentation; however, the mechanism is unclear. Here, we show that DNA-damage-induced HLA (di-HLA) presentation requires an immunoproteasome, PSMB8/9/10, and antigen-transporter, TAP1/2, demonstrating that antigen production is essential. Furthermore, we show that di-HLA presentation requires ATR, AKT, mTORC1, and p70-S6K signaling. Notably, the depletion of CBP20, a factor initiating the pioneer round of translation (PRT) that precedes nonsense-mediated mRNA decay (NMD), abolishes di-HLA presentation, suggesting that di-antigen production requires PRT. RNA-seq analysis demonstrates that DNA damage reduces NMD transcripts in an ATR-dependent manner, consistent with the requirement for ATR in the initiation of PRT/NMD. Finally, bioinformatics analysis identifies that PRT-derived 9-mer peptides bind to HLA and are potentially immunogenic. Therefore, DNA damage signaling produces immunogenic antigens by utilizing the machinery of PRT/NMD.


Asunto(s)
Degradación de ARNm Mediada por Codón sin Sentido , Biosíntesis de Proteínas , Presentación de Antígeno , Daño del ADN , Antígenos de Histocompatibilidad Clase I/genética , Humanos
2.
Genes Dev ; 35(21-22): 1431-1444, 2021 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-34675062

RESUMEN

During neocortical development, tight regulation of neurogenesis-to-astrogenesis switching of neural precursor cells (NPCs) is critical to generate a balanced number of each neural cell type for proper brain functions. Accumulating evidence indicates that a complex array of epigenetic modifications and the availability of extracellular factors control the timing of neuronal and astrocytic differentiation. However, our understanding of NPC fate regulation is still far from complete. Bone morphogenetic proteins (BMPs) are renowned as cytokines that induce astrogenesis of gliogenic late-gestational NPCs. They also promote neurogenesis of mid-gestational NPCs, although the underlying mechanisms remain elusive. By performing multiple genome-wide analyses, we demonstrate that Smads, transcription factors that act downstream from BMP signaling, target dramatically different genomic regions in neurogenic and gliogenic NPCs. We found that histone H3K27 trimethylation and DNA methylation around Smad-binding sites change rapidly as gestation proceeds, strongly associated with the alteration of accessibility of Smads to their target binding sites. Furthermore, we identified two lineage-specific Smad-interacting partners-Sox11 for neurogenic and Sox8 for astrocytic differentiation-that further ensure Smad-regulated fate-specific gene induction. Our findings illuminate an exquisite regulation of NPC property change mediated by the interplay between cell-extrinsic cues and -intrinsic epigenetic programs during cortical development.


Asunto(s)
Células-Madre Neurales , Encéfalo , Diferenciación Celular/genética , Epigénesis Genética , Femenino , Estudio de Asociación del Genoma Completo , Humanos , Neurogénesis/genética , Embarazo , Factores de Transcripción SOXE/genética
3.
Cell ; 148(1-2): 24-8, 2012 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-22265398

RESUMEN

Chromatin-modifying enzymes have long been proposed to be the authors of an epigenetic language, but the origin and meaning of the messages they write in chromatin are still mysterious. Recent studies suggesting that the effects of diet can be passed on epigenetically to offspring add weight to the idea that histones act as metabolic sensors, converting changes in metabolism into stable patterns of gene expression. The challenge will now be to understand how localized fluctuations in levels of metabolites control chromatin modifiers in space and time, translating a dynamic metabolic state into a histone map.


Asunto(s)
Epigénesis Genética , Eucariontes/genética , Eucariontes/metabolismo , Redes y Vías Metabólicas , Ensamble y Desensamble de Cromatina , Código de Histonas , Histonas/metabolismo , NAD/metabolismo
4.
Development ; 148(14)2021 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-34184026

RESUMEN

Transcription factor 4 (TCF4) is a crucial regulator of neurodevelopment and has been linked to the pathogenesis of autism, intellectual disability and schizophrenia. As a class I bHLH transcription factor (TF), it is assumed that TCF4 exerts its neurodevelopmental functions through dimerization with proneural class II bHLH TFs. Here, we aim to identify TF partners of TCF4 in the control of interhemispheric connectivity formation. Using a new bioinformatic strategy integrating TF expression levels and regulon activities from single cell RNA-sequencing data, we find evidence that TCF4 interacts with non-bHLH TFs and modulates their transcriptional activity in Satb2+ intercortical projection neurons. Notably, this network comprises regulators linked to the pathogenesis of neurodevelopmental disorders, e.g. FOXG1, SOX11 and BRG1. In support of the functional interaction of TCF4 with non-bHLH TFs, we find that TCF4 and SOX11 biochemically interact and cooperatively control commissure formation in vivo, and regulate the transcription of genes implicated in this process. In addition to identifying new candidate interactors of TCF4 in neurodevelopment, this study illustrates how scRNA-Seq data can be leveraged to predict TF networks in neurodevelopmental processes.


Asunto(s)
ARN Citoplasmático Pequeño/metabolismo , Análisis de la Célula Individual , Factor de Transcripción 4/genética , Factor de Transcripción 4/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Diferenciación Celular , ADN Helicasas , Embrión de Mamíferos , Factores de Transcripción Forkhead , Regulación del Desarrollo de la Expresión Génica , Redes Reguladoras de Genes , Discapacidad Intelectual , Proteínas de Unión a la Región de Fijación a la Matriz , Ratones , Ratones Noqueados , Proteínas del Tejido Nervioso , Neuronas/fisiología , Proteínas Nucleares , Dominios y Motivos de Interacción de Proteínas , ARN Citoplasmático Pequeño/genética , Factores de Transcripción SOXC , Esquizofrenia/genética , Esquizofrenia/metabolismo
5.
Glia ; 68(8): 1554-1567, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32163194

RESUMEN

The nervous system consists of several hundred neuronal subtypes and glial cells that show specific gene expression and are generated from common ancestors, neural stem cells (NSCs). As the experimental techniques and molecular tools to analyze epigenetics and chromatin structures are rapidly advancing, the comprehensive events and genome-wide states of DNA methylation, histone modifications, and chromatin accessibility in developing NSCs are gradually being unveiled. Here, we review recent advances in elucidating the role of epigenetic and chromatin regulation in NSCs, especially focusing on the acquisition of glial identity and how epigenetic regulation enables the temporal regulation of NSCs during murine cortical development.


Asunto(s)
Diferenciación Celular/fisiología , Epigénesis Genética/fisiología , Células-Madre Neurales/fisiología , Neuroglía/metabolismo , Animales , Cromatina/metabolismo , Humanos , Neurogénesis/fisiología
6.
J Neurochem ; 142(6): 901-907, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28695568

RESUMEN

Arginine methylation is a post-translational modification which is catalyzed by protein arginine methyltransferases (PRMTs). Here, we report that PRMT1 is highly expressed in neural stem/precursor cells (NS/PCs) of mouse embryos, and knockdown of PRMT1 in NS/PCs suppresses the generation of astrocytes. The luciferase assay demonstrated that knockdown of PRMT1 inhibits activation of the promoter of a typical astrocytic marker gene, glial fibrillary acidic protein (Gfap), in NS/PCs. The transcription factor signal transducer and activator of transcription 3 (STAT3) is known to generally be critical for astrocytic differentiation of NS/PCs. We found that PRMT1 methylates arginine residue(s) of STAT3 to regulate its activity positively, resulting in the promotion of astrocytic differentiation of NS/PCs.

7.
Proc Jpn Acad Ser B Phys Biol Sci ; 93(6): 386-398, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28603210

RESUMEN

In the developing brain, the three major cell types, i.e., neurons, astrocytes and oligodendrocytes, are generated from common multipotent neural stem cells (NSCs). In particular, astrocytes eventually occupy a great fraction of the brain and play pivotal roles in the brain development and functions. However, NSCs cannot produce the three major cell types simultaneously from the beginning; e.g., it is known that neurogenesis precedes astrogenesis during brain development. How is this fate switching achieved? Many studies have revealed that extracellular cues and intracellular programs are involved in the transition of NSC fate specification. The former include growth factor- and cytokine-signaling, and the latter involve epigenetic machinery, including DNA methylation, histone modifications, and non-coding RNAs. Accumulating evidence has identified a complex array of epigenetic modifications that control the timing of astrocytic differentiation of NSCs. In this review, we introduce recent progress in identifying the molecular mechanisms of astrogenesis underlying the tight regulation of neuronal-astrocytic fate switching of NSCs.


Asunto(s)
Astrocitos/citología , Astrocitos/fisiología , Encéfalo/citología , Diferenciación Celular , Células-Madre Neurales/fisiología , Animales , Encéfalo/crecimiento & desarrollo , Diferenciación Celular/genética , Cromatina/metabolismo , Metilación de ADN , Epigénesis Genética , Código de Histonas , Humanos , Mamíferos , Células-Madre Neurales/química , Neuronas/química , Neuronas/metabolismo , ARN no Traducido , Transducción de Señal
8.
J Neurosci ; 33(32): 12987-96, 12996a, 2013 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-23926254

RESUMEN

The basic scheme of odor perception and signaling from olfactory cilia to the brain is well understood. However, factors that affect olfactory acuity of an animal, the threshold sensitivity to odorants, are less well studied. Using signal sequence trap screening of a mouse olfactory epithelium cDNA library, we identified a novel molecule, Goofy, that is essential for olfactory acuity in mice. Goofy encodes an integral membrane protein with specific expression in the olfactory and vomeronasal sensory neurons and predominant localization to the Golgi compartment. Goofy-deficient mice display aberrant olfactory phenotypes, including the impaired trafficking of adenylyl cyclase III, stunted olfactory cilia, and a higher threshold for physiological and behavioral responses to odorants. In addition, the expression of dominant-negative form of cAMP-dependent protein kinase results in shortening of olfactory cilia, implying a possible mechanistic link between cAMP and ciliogenesis in the olfactory sensory neurons. These results demonstrate that Goofy plays an important role in establishing the acuity of olfactory sensory signaling.


Asunto(s)
Proteínas de Unión al GTP/metabolismo , Odorantes , Vías Olfatorias/metabolismo , Neuronas Receptoras Olfatorias/fisiología , Transducción de Señal/fisiología , Adenilil Ciclasas/metabolismo , Animales , Clonación Molecular , Proteínas Quinasas Dependientes de AMP Cíclico/genética , Canales Catiónicos Regulados por Nucleótidos Cíclicos/genética , Canales Catiónicos Regulados por Nucleótidos Cíclicos/metabolismo , Potenciales Evocados/genética , Proteínas de Unión al GTP/deficiencia , Proteínas de Unión al GTP/genética , Regulación de la Expresión Génica/genética , Proteínas Luminiscentes/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Proteína Marcadora Olfativa/genética , Proteína Marcadora Olfativa/metabolismo , Vías Olfatorias/anatomía & histología , ARN Mensajero , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Análisis de Secuencia , Transducción de Señal/genética , Transactivadores/genética , Transactivadores/metabolismo
9.
Pharmacol Res Perspect ; 9(6): e00749, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34677001

RESUMEN

The brain consists of three major cell types: neurons and two glial cell types (astrocytes and oligodendrocytes). Although they are generated from common multipotent neural stem/precursor cells (NS/PCs), embryonic NS/PCs cannot generate all of the cell types at the beginning of brain development. NS/PCs first undergo extensive self-renewal to expand their pools, and then acquire the potential to produce neurons, followed by glial cells. Astrocytes are the most frequently found cell type in the central nervous system (CNS), and play important roles in brain development and functions. Although it has been shown that nuclear factor IA (Nfia) is a pivotal transcription factor for conferring gliogenic potential on neurogenic NS/PCs by sequestering DNA methyltransferase 1 (Dnmt1) from astrocyte-specific genes, direct targets of Nfia that participate in astrocytic differentiation have yet to be completely identified. Here we show that SRY-box transcription factor 8 (Sox8) is a direct target gene of Nfia at the initiation of the gliogenic phase. We found that expression of Sox8 augmented leukemia inhibitory factor (LIF)-induced astrocytic differentiation, while Sox8 knockdown inhibited Nfia-enhanced astrocytic differentiation of NS/PCs. In contrast to Nfia, Sox8 did not induce DNA demethylation of an astrocyte-specific marker gene, glial fibrillary acidic protein (Gfap), but instead associated with LIF downstream transcription factor STAT3 through transcriptional coactivator p300, explaining how Sox8 expression further facilitated LIF-induced Gfap expression. Taken together, these results suggest that Sox8 is a crucial Nfia downstream transcription factor for the astrocytic differentiation of NS/PCs in the developing brain.


Asunto(s)
Astrocitos/citología , Factores de Transcripción NFI/genética , Células-Madre Neurales/citología , Factores de Transcripción SOXE/genética , Animales , Diferenciación Celular , Células Cultivadas , Factor Inhibidor de Leucemia/metabolismo , Ratones , Ratones Endogámicos ICR , Neurogénesis/fisiología , Neuronas/citología
10.
Neuron ; 52(5): 857-69, 2006 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-17145506

RESUMEN

Odorant identity is represented in the olfactory bulb (OB) by the glomerular activity pattern, which reflects a combination of activated odorant receptors (ORs) in the olfactory epithelium. To elucidate this neuronal circuit at the molecular level, we established a functional OR identification strategy based on glomerular activity by combining in vivo Ca(2+) imaging, retrograde dye labeling, and single-cell RT-PCR. Spatial and functional mapping of OR-defined glomeruli revealed that the glomerular positional relationship varied considerably between individual animals, resulting in different OR maps in the OB. Notably, OR-defined glomeruli exhibited different ligand spectra and far higher sensitivity compared to the in vitro pharmacological properties of corresponding ORs. Moreover, we found that the olfactory mucus was an important factor in the regulation of in vivo odorant responsiveness. Our results provide a methodology to examine in vivo glomerular responses at the receptor level and further help address the long-standing issues of olfactory sensitivity and specificity under physiological conditions.


Asunto(s)
Bulbo Olfatorio/fisiología , Vías Olfatorias/fisiología , Neuronas Receptoras Olfatorias/fisiología , Animales , Calcio/metabolismo , Línea Celular , Clonación Molecular , AMP Cíclico/metabolismo , Relación Dosis-Respuesta a Droga , Eugenol/análogos & derivados , Eugenol/farmacología , Hemiterpenos , Humanos , Procesamiento de Imagen Asistido por Computador , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mucosa Nasal/fisiología , Odorantes , Bulbo Olfatorio/efectos de los fármacos , Mucosa Olfatoria/efectos de los fármacos , Mucosa Olfatoria/fisiología , Vías Olfatorias/efectos de los fármacos , Neuronas Receptoras Olfatorias/efectos de los fármacos , Ácidos Pentanoicos/farmacología , ARN Mensajero/biosíntesis , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
11.
PLoS One ; 15(11): e0241758, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33237909

RESUMEN

Ethologically relevant chemical senses and behavioral habits are likely to coadapt in response to selection. As olfaction is involved in intrinsically motivated behaviors in mice, we hypothesized that selective breeding for a voluntary behavior would enable us to identify novel roles of the chemosensory system. Voluntary wheel running (VWR) is an intrinsically motivated and naturally rewarding behavior, and even wild mice run on a wheel placed in nature. We have established 4 independent, artificially evolved mouse lines by selectively breeding individuals showing high VWR activity (High Runners; HRs), together with 4 non-selected Control lines, over 88 generations. We found that several sensory receptors in specific receptor clusters were differentially expressed between the vomeronasal organ (VNO) of HRs and Controls. Moreover, one of those clusters contains multiple single-nucleotide polymorphism loci for which the allele frequencies were significantly divergent between the HR and Control lines, i.e., loci that were affected by the selective breeding protocol. These results indicate that the VNO has become genetically differentiated between HR and Control lines during the selective breeding process. Although the role of the vomeronasal chemosensory receptors in VWR activity remains to be determined, the current results suggest that these vomeronasal chemosensory receptors are important quantitative trait loci for voluntary exercise in mice. We propose that olfaction may play an important role in motivation for voluntary exercise in mammals.


Asunto(s)
Conducta Animal , Condicionamiento Físico Animal , Órgano Vomeronasal/metabolismo , Animales , Femenino , Frecuencia de los Genes , Sitios Genéticos , Masculino , Ratones , Ratones Endogámicos ICR , Polimorfismo de Nucleótido Simple , Selección Genética
12.
J Neurochem ; 107(5): 1261-70, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18803693

RESUMEN

Thousands of different odorants are recognized and discriminated by odorant receptors (ORs) in the guanine nucleotide-binding protein (G protein)-coupled seven-transmembrane receptor family. Odorant-bound ORs stimulate Gs-type G proteins, Galphaolf, which in turn activates cAMP-mediated signaling pathway in olfactory sensory neurons. To better understand the molecular basis for OR activation and G protein coupling, we analyzed the effects of a series of site-directed mutations of mouse ORs, on function. Mutations of conserved amino acid residues in an intracellular loop or the C-terminus resulted in loss of activity without impairing ligand-binding activity, indicating that these residues are involved in Galphas/olf coupling. Moreover, mutation of the serine in KAFSTC, the OR-specific sequence motif, resulted in a dramatic increase in odorant responsiveness, suggesting that the motif is involved in a conformational change of the receptor that regulates G protein coupling efficiency. Our results provide insights into how ORs switch from an inactive to an active state, as well as where and how activated ORs interact with G proteins.


Asunto(s)
Aminoácidos/metabolismo , Proteínas de Unión al GTP/metabolismo , Mutación , Receptores Odorantes/metabolismo , Calcio/metabolismo , Línea Celular , AMP Cíclico/metabolismo , Citometría de Flujo , Humanos , Inmunoprecipitación , Mutagénesis Sitio-Dirigida/métodos , Dinámicas no Lineales , Estructura Secundaria de Proteína , Receptores Odorantes/química , Receptores Odorantes/genética , Relación Estructura-Actividad , Transfección/métodos
13.
Results Probl Cell Differ ; 66: 125-136, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30209657

RESUMEN

Emerging evidence has demonstrated that epigenetic programs influence many aspects of neural stem cell (NSC) behavior, including proliferation and differentiation. It is becoming apparent that epigenetic mechanisms, such as DNA methylation, histone modifications, and noncoding RNA expression, are spatiotemporally regulated and that these intracellular programs, in concert with extracellular signals, ensure appropriate gene activation. Here we summarize recent advances in understanding of the epigenetic regulation of human NSCs directly isolated from the brain or produced from pluripotent stem cells (embryonic and induced pluripotent stem cells, respectively).


Asunto(s)
Diferenciación Celular/genética , Epigénesis Genética , Células-Madre Neurales/citología , Células-Madre Neurales/metabolismo , Células Madre Embrionarias/citología , Humanos , Células Madre Pluripotentes Inducidas/citología
14.
FEBS Lett ; 591(22): 3709-3720, 2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-29029363

RESUMEN

Astrocytes, which support diverse neuronal functions, are generated from multipotent neural stem/precursor cells (NS/PCs) during brain development. Although many astrocyte-inducing factors have been identified and studied in vitro, the regions and/or cells that produce these factors in the developing brain remain elusive. Here, we show that meninges-produced factors induce astrocytic differentiation of NS/PCs. Consistent with the timing when astrocytic differentiation of NS/PCs increases, expression of astrocyte-inducing factors is upregulated. Meningeal secretion-mimicking combinatorial treatment of NS/PCs with bone morphogenetic protein 4, retinoic acid and leukemia inhibitory factor synergistically activate the promoter of a typical astrocytic marker, glial fibrillary acidic protein. Taken together, our data suggest that meninges play an important role in astrocytic differentiation of NS/PCs in the developing brain.


Asunto(s)
Astrocitos/citología , Encéfalo/crecimiento & desarrollo , Proteína Ácida Fibrilar de la Glía/genética , Meninges/metabolismo , Células Madre Embrionarias de Ratones/citología , Animales , Proteína Morfogenética Ósea 4/metabolismo , Encéfalo/citología , Diferenciación Celular , Células Cultivadas , Técnicas de Cocultivo , Medios de Cultivo Condicionados/farmacología , Factor Inhibidor de Leucemia/metabolismo , Meninges/citología , Ratones , Neurogénesis , Tretinoina/metabolismo
15.
J Neurosci ; 25(7): 1806-15, 2005 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-15716417

RESUMEN

The olfactory receptor (OR) superfamily provides a basis for the remarkable ability to recognize and discriminate a large number of odorants. In mice, the superfamily includes approximately 1000 members, and they recognize overlapping sets of odorants with distinct affinities and specificities. To address the molecular basis of odor discrimination by the mammalian OR superfamily, we performed functional analysis on a series of site-directed mutants and performed ligand docking simulation studies to define the odorant-binding site of a mouse OR. Our results indicate that several amino acids in the transmembrane domains formed a ligand-binding pocket. Although other G-protein-coupled receptors (GPCRs) recognize biogenic ligands mainly with ionic or hydrogen bonding interactions, ORs recognize odorants mostly via hydrophobic and van der Waals interactions. This accounts for the broad but selective binding by ORs as well as their relatively low ligand-binding affinities. Furthermore, we succeeded in rational receptor design, inserting point mutations in the odorant-binding site that resulted in predicted changes in ligand specificity and antagonist activity. This ability to rationally design the receptor validated the binding site structure that was deduced with our mutational and ligand docking studies. Such broad and specific sensitivity suggests an evolutionary process during which mutations in the active site led to an enormous number of ORs with a wide range of ligand specificity. The current study reveals the molecular environment of the odorant-binding site, and it further advances the understanding of GPCR pharmacology.


Asunto(s)
Concentración de Iones de Hidrógeno , Receptores Odorantes/química , Regulación Alostérica , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Sitios de Unión , Calcio/metabolismo , Línea Celular , Simulación por Computador , Diseño de Fármacos , Eugenol/farmacología , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Riñón , Ligandos , Ratones , Modelos Moleculares , Datos de Secuencia Molecular , Familia de Multigenes , Mutagénesis Sitio-Dirigida , Mutación Missense , Odorantes , Mutación Puntual , Unión Proteica , Conformación Proteica , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/fisiología , Receptores Odorantes/fisiología , Relación Estructura-Actividad , Especificidad por Sustrato
16.
Nat Struct Mol Biol ; 22(4): 312-8, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25751424

RESUMEN

The circadian clock controls the transcription of hundreds of genes through specific chromatin-remodeling events. The histone methyltransferase mixed-lineage leukemia 1 (MLL1) coordinates recruitment of CLOCK-BMAL1 activator complexes to chromatin, an event associated with cyclic trimethylation of histone H3 Lys4 (H3K4) at circadian promoters. Remarkably, in mouse liver circadian H3K4 trimethylation is modulated by SIRT1, an NAD(+)-dependent deacetylase involved in clock control. We show that mammalian MLL1 is acetylated at two conserved residues, K1130 and K1133. Notably, MLL1 acetylation is cyclic, controlled by the clock and by SIRT1, and it affects the methyltransferase activity of MLL1. Moreover, H3K4 methylation at clock-controlled-gene promoters is influenced by pharmacological or genetic inactivation of SIRT1. Finally, levels of MLL1 acetylation and H3K4 trimethylation at circadian gene promoters depend on NAD(+) circadian levels. These findings reveal a previously unappreciated regulatory pathway between energy metabolism and histone methylation.


Asunto(s)
Relojes Circadianos/genética , Histonas/metabolismo , Proteína de la Leucemia Mieloide-Linfoide/metabolismo , NAD/fisiología , Sirtuina 1/fisiología , Acetilación , Animales , Cromatina , Regulación de la Expresión Génica , Metilación , Ratones , Modelos Genéticos , NAD/metabolismo , Sirtuina 1/metabolismo
17.
Ann N Y Acad Sci ; 1264: 103-9, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22834651

RESUMEN

Chromatin remodeling is a prerequisite for most nuclear functions, including transcription, silencing, and DNA replication. Accumulating evidence shows that many physiological processes require highly sophisticated events of chromatin remodeling. Recent findings have linked cellular metabolism, epigenetic state, and the circadian clock. The control of a large variety of neuronal, behavioral, and physiological responses follows diurnal rhythms. This is possible through a transcriptional regulatory network that governs a significant portion of the genome. The harmonic oscillation of gene expression is paralleled by critical events of chromatin remodeling that appear to provide specificity and plasticity in circadian regulation. Accumulating evidence shows that the circadian epigenome appears to share intimate links with cellular metabolic processes. These notions indicate that the circadian epigenome might integrate tissue specificity within biological pacemakers, bridging systems physiology to metabolic control. This review highlights several advances related to the circadian epigenome, the contribution of NAD+ as a critical signaling metabolite, and its effects on epigenetic state, followed by more recent reports on circadian metabolomics analyses.


Asunto(s)
Ensamble y Desensamble de Cromatina , Relojes Circadianos , Ritmo Circadiano/fisiología , Epigénesis Genética , Retroalimentación Fisiológica , Transcripción Genética , Relojes Circadianos/genética , Relojes Circadianos/fisiología , Ritmo Circadiano/genética , Regulación de la Expresión Génica , Humanos , Transducción de Señal
18.
Nat Struct Mol Biol ; 17(12): 1414-21, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21113167

RESUMEN

The classical view of the molecular clock is based on interlocked transcriptional-translational feedback loops. Because a substantial fraction of the mammalian genome is expressed in a circadian manner, chromatin remodeling has been proposed to be crucial in clock function. Here we show that Lys4 (K4) trimethylation of histone H3 is rhythmic and follows the same profile as previously described H3 acetylation on circadian promoters. MLL1, a mammalian homolog of Drosophila trithorax, is an H3K4-specific methyltransferase implicated in transcriptional control. We demonstrate that MLL1 is essential for circadian transcription and cyclic H3K4 trimethylation. MLL1 is in a complex with CLOCK-BMAL1 and contributes to its rhythmic recruitment to circadian promoters and to H3 acetylation. Yet MLL1 fails to interact with CLOCKΔ19, providing an explanation for this mutation's dominant negative phenotype. Our results favor a scenario in which H3K4 trimethylation by MLL1 is required to establish a permissive chromatin state for circadian transcription.


Asunto(s)
Ritmo Circadiano/genética , Regulación de la Expresión Génica , N-Metiltransferasa de Histona-Lisina/fisiología , Histonas/metabolismo , Proteína de la Leucemia Mieloide-Linfoide/fisiología , Factores de Transcripción ARNTL/metabolismo , Acetilación , Animales , Proteínas CLOCK/genética , Proteínas CLOCK/metabolismo , Ensamble y Desensamble de Cromatina , Histona Metiltransferasas , N-Metiltransferasa de Histona-Lisina/metabolismo , Humanos , Metilación , Ratones , Modelos Genéticos , Proteína de la Leucemia Mieloide-Linfoide/metabolismo , Activación Transcripcional
19.
Cell Metab ; 12(5): 509-20, 2010 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-21035761

RESUMEN

Accumulating evidence highlights intriguing interplays between circadian and metabolic pathways. We show that PER2 directly and specifically represses PPARγ, a nuclear receptor critical in adipogenesis, insulin sensitivity, and inflammatory response. PER2-deficient mice display altered lipid metabolism with drastic reduction of total triacylglycerol and nonesterified fatty acids. PER2 exerts its inhibitory function by blocking PPARγ recruitment to target promoters and thereby transcriptional activation. Whole-genome microarray profiling demonstrates that PER2 dictates the specificity of PPARγ transcriptional activity. Indeed, lack of PER2 results in enhanced adipocyte differentiation of cultured fibroblasts. PER2 targets S112 in PPARγ, a residue whose mutation has been associated with altered lipid metabolism. Lipidomic profiling demonstrates that PER2 is necessary for normal lipid metabolism in white adipocyte tissue. Our findings support a scenario in which PER2 controls the proadipogenic activity of PPARγ by operating as its natural modulator, thereby revealing potential avenues of pharmacological and therapeutic intervention.


Asunto(s)
Metabolismo de los Lípidos , PPAR gamma/metabolismo , Proteínas Circadianas Period/metabolismo , Activación Transcripcional , Células 3T3-L1 , Adipocitos/citología , Adipocitos/metabolismo , Adipogénesis , Animales , Eliminación de Gen , Expresión Génica , Ratones , Células 3T3 NIH , PPAR gamma/genética , Proteínas Circadianas Period/genética , Dominios y Motivos de Interacción de Proteínas
20.
Nihon Yakurigaku Zasshi ; 124(4): 201-9, 2004 Oct.
Artículo en Japonés | MEDLINE | ID: mdl-15467253

RESUMEN

Olfactory receptors (ORs) comprise the largest super-family of rhodopsin-like G-protein coupled receptors (GPCR) that involve the recognition and discrimination of thousands of odorants. We recently succeeded in functional reconstitution of mouse ORs in mammalian cell lines and provided molecular evidence that structurally-related ORs recognized overlapping sets of odorants with distinct ligand specificities. Here we show that mOR-EG, a mouse olfactory receptor that was isolated from a eugenol-responsive cell, recognizes 22 different odorants with EC50 values ranging from a few microM to several hundred microM. We constructed a molecular model of mOR-EG using the recent atomic-level structure of bovine rhodopsin. Site-directed mutations were introduced in a potential ligand-binding pocket based on computational ligand-docking simulation. Mutations of some amino acid residues in TM3, TM5, and TM6 dramatically affected the EC50 value of eugenol in Ca2+ imaging. Finally, we succeeded in rational receptor design with predicted ligand specificity by introducing point mutations in the binding site, confirming the accuracy of the binding site mapping. The current studies also help understand mechanisms underlying molecular recognition by GPCRs, with implications for therapeutic application.


Asunto(s)
Células Receptoras Sensoriales/fisiología , Olfato/fisiología , Animales , Simulación por Computador , Humanos , Ligandos , Modelos Moleculares , Receptores Acoplados a Proteínas G/fisiología
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