RESUMEN
Mouse postnatal neural stem cells (pNSCs) can be expanded in vitro in the presence of epidermal growth factor and fibroblast growth factor 2 and upon removal of these factors cease proliferation and generate neurons, astrocytes, and oligodendrocytes. The genetic requirements for self-renewal and lineage-commitment of pNSCs are incompletely understood. In this study, we show that the transcription factors NFIA and NFIB, previously shown individually, to be essential for the normal commitment of pNSCs to the astrocytic lineage in vivo, are jointly required for normal self-renewal of pNSCs in vitro and in vivo. Using conditional knockout alleles of Nfia and Nfib, we show that the simultaneous loss of these two genes under self-renewal conditions in vitro reduces the expression of the proliferation markers PCNA and Ki67, eliminates clonogenicity of the cells, reduces the number of cells in S phase, and induces aberrant differentiation primarily into the neuroblast lineage. This phenotype requires the loss of both genes and is not seen upon loss of Nfia or Nfib alone, nor with combined loss of Nfia and Nfix or Nfib and Nfix. These data demonstrate a unique combined requirement for both Nfia and Nfib for pNSC self-renewal.
Asunto(s)
Factores de Transcripción NFI , Células-Madre Neurales , Animales , Ratones , Diferenciación Celular/fisiología , Autorrenovación de las Células , Células-Madre Neurales/metabolismo , Neuronas/metabolismo , Factores de Transcripción NFI/genética , Factores de Transcripción NFI/metabolismoRESUMEN
Olfactory receptor (OR) choice represents an example of genetically hardwired stochasticity, where every olfactory neuron expresses one out of ~2000 OR alleles in the mouse genome in a probabilistic, yet stereotypic fashion. Here, we propose that topographic restrictions in OR expression are established in neuronal progenitors by two opposing forces: polygenic transcription and genomic silencing, both of which are influenced by dorsoventral gradients of transcription factors NFIA, B, and X. Polygenic transcription of OR genes may define spatially constrained OR repertoires, among which one OR allele is selected for singular expression later in development. Heterochromatin assembly and genomic compartmentalization of OR alleles also vary across the axes of the olfactory epithelium and may preferentially eliminate ectopically expressed ORs with more dorsal expression destinations from this 'privileged' repertoire. Our experiments identify early transcription as a potential 'epigenetic' contributor to future developmental patterning and reveal how two spatially responsive probabilistic processes may act in concert to establish deterministic, precise, and reproducible territories of stochastic gene expression.
Asunto(s)
Neuronas Receptoras Olfatorias , Receptores Odorantes , Animales , Ratones , Receptores Odorantes/genética , Epigenómica , Alelos , Epigénesis GenéticaRESUMEN
Olfactory receptor (OR) choice represents an example of genetically hardwired stochasticity, where every olfactory neuron expresses one out of ~2000 OR alleles in a probabilistic, yet stereotypic fashion. Here, we propose that topographic restrictions in OR expression are established in neuronal progenitors by two opposing forces: polygenic transcription and genomic silencing, both of which are influenced by dorsoventral gradients of transcription factors NFIA, B, and X. Polygenic transcription of OR genes may define spatially constrained OR repertoires, among which one OR allele is selected for singular expression later in development. Heterochromatin assembly and genomic compartmentalization of OR alleles also vary across the axes of the olfactory epithelium and may preferentially eliminate ectopically expressed ORs with more dorsal expression destinations from this "privileged" repertoire. Our experiments identify early transcription as a potential "epigenetic" contributor to future developmental patterning and reveal how two spatially responsive probabilistic processes may act in concert to establish deterministic, precise, and reproducible territories of stochastic gene expression.
RESUMEN
Members of the nuclear factor I (NFI) family are key regulators of stem cell biology during development, with well-documented roles for NFIA, NFIB, and NFIX in a variety of developing tissues, including brain, muscle, and lung. Given the central role these factors play in stem cell biology, we posited that they may be pivotal for spermatogonial stem cells or further developing spermatogonia during testicular development. Surprisingly, in stark contrast to other developing organ systems where NFI members are co-expressed, these NFI family members show discrete patterns of expression within the seminiferous tubules. Sertoli cells (spermatogenic supporting cells) express NFIA, spermatocytes express NFIX, round spermatids express NFIB, and peritubular myoid cells express each of these three family members. Further analysis of NFIX expression during the cycle of the seminiferous epithelium revealed expression not in spermatogonia, as we anticipated, but in spermatocytes. These data suggested a potential role for NFIX in spermatogenesis. To investigate, we analyzed mice with constitutive deletion of Nfix (Nfix-null). Assessment of germ cells in the postnatal day 20 (P20) testes of Nfix-null mice revealed that spermatocytes initiate meiosis, but zygotene stage spermatocytes display structural defects in the synaptonemal complex, and increased instances of unrepaired DNA double-strand breaks. Many developing spermatocytes in the Nfix-null testis exhibited multinucleation. As a result of these defects, spermatogenesis is blocked at early diplotene and very few round spermatids are produced. Collectively, these novel data establish the global requirement for NFIX in correct meiotic progression during the first wave of spermatogenesis.
Asunto(s)
Factores de Transcripción NFI , Espermatogonias , Testículo , Animales , Masculino , Meiosis , Ratones , Ratones Noqueados , Factores de Transcripción NFI/genética , Factores de Transcripción NFI/metabolismo , Espermatocitos/metabolismo , Espermatogénesis/genética , Testículo/metabolismoRESUMEN
Nuclear factor one (NFI) transcription factors are implicated in both brain development and cancer in mice and humans and play an essential role in glial differentiation. NFI expression is reduced in human astrocytoma samples, particularly those of higher grade, whereas over-expression of NFI protein can induce the differentiation of glioblastoma cells within human tumour xenografts and in glioblastoma cell lines in vitro. These data indicate that NFI proteins may act as tumour suppressors in glioma. To test this hypothesis, we generated complex mouse genetic crosses involving six alleles to target gene deletion of known tumour suppressor genes that induce endogenous high-grade glioma in mice, and overlaid this with loss of function Nfi mutant alleles, Nfia and Nfib, a reporter transgene and an inducible Cre allele. Deletion of Nfi resulted in reduced survival time of the mice, increased tumour load and a more aggressive tumour phenotype than observed in glioma mice with normal expression of NFI. Together, these data indicate that NFI genes represent a credible target for both diagnostic analyses and therapeutic strategies to combat high-grade glioma.
Asunto(s)
Neoplasias Encefálicas/genética , Glioblastoma/genética , Factores de Transcripción NFI/metabolismo , Animales , Neoplasias Encefálicas/patología , Modelos Animales de Enfermedad , Glioblastoma/patología , Humanos , Masculino , Ratones , Ratones Noqueados , Factores de Transcripción NFI/genéticaRESUMEN
OBJECTIVE: Nuclear Factor One X (NFIX) is a transcription factor expressed by neural stem cells within the developing mouse brain and spinal cord. In order to characterise the pathways by which NFIX may regulate neural stem cell biology within the developing mouse spinal cord, we performed an microarray-based transcriptomic analysis of the spinal cord of embryonic day (E)14.5 Nfix-/- mice in comparison to wild-type controls. DATA DESCRIPTION: Using microarray and differential gene expression analyses, we were able to identify differentially expressed genes in the spinal cords of E14.5 Nfix-/- mice compared to wild-type controls. We performed microarray-based sequencing on spinal cords from n = 3 E14.5 Nfix-/- mice and n = 3 E14.5 Nfix+/+ mice. Differential gene expression analysis, using a false discovery rate (FDR) p-value of p < 0.05, and a fold change cut-off for differential expression of > ± 1.5, revealed 1351 differentially regulated genes in the spinal cord of Nfix-/- mice. Of these, 828 were upregulated, and 523 were downregulated. This resource provides a tool to interrogate the role of this transcription factor in spinal cord development.
Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Factores de Transcripción NFI , Animales , Expresión Génica , Ratones , Ratones Endogámicos C57BL , Factores de Transcripción NFI/genética , Médula EspinalRESUMEN
Tissue homeostasis and regeneration rely on resident stem cells (SCs), whose behaviour is regulated through niche-dependent crosstalk. The mechanisms underlying SC identity are still unfolding. Here, using spatiotemporal gene ablation in murine hair follicles, we uncover a critical role for the transcription factors (TFs) nuclear factor IB (NFIB) and IX (NFIX) in maintaining SC identity. Without NFI TFs, SCs lose their hair-regenerating capability, and produce skin bearing striking resemblance to irreversible human alopecia, which also displays reduced NFIs. Through single-cell transcriptomics, ATAC-Seq and ChIP-Seq profiling, we expose a key role for NFIB and NFIX in governing super-enhancer maintenance of the key hair follicle SC-specific TF genes. When NFIB and NFIX are genetically removed, the stemness epigenetic landscape is lost. Super-enhancers driving SC identity are decommissioned, while unwanted lineages are de-repressed ectopically. Together, our findings expose NFIB and NFIX as crucial rheostats of tissue homeostasis, functioning to safeguard the SC epigenome from a breach in lineage confinement that otherwise triggers irreversible tissue degeneration.
Asunto(s)
Alopecia/patología , Diferenciación Celular , Cromatina/metabolismo , Folículo Piloso/citología , Factores de Transcripción NFI/fisiología , Células Madre/citología , Alopecia/genética , Alopecia/metabolismo , Animales , Células Cultivadas , Cromatina/genética , Femenino , Folículo Piloso/metabolismo , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Regeneración , Células Madre/metabolismoRESUMEN
Changes in potential regulatory elements are thought to be key drivers of phenotypic divergence. However, identifying changes to regulatory elements that underlie human-specific traits has proven very challenging. Here, we use 63 reconstructed and experimentally measured DNA methylation maps of ancient and present-day humans, as well as of six chimpanzees, to detect differentially methylated regions that likely emerged in modern humans after the split from Neanderthals and Denisovans. We show that genes associated with face and vocal tract anatomy went through particularly extensive methylation changes. Specifically, we identify widespread hypermethylation in a network of face- and voice-associated genes (SOX9, ACAN, COL2A1, NFIX and XYLT1). We propose that these repression patterns appeared after the split from Neanderthals and Denisovans, and that they might have played a key role in shaping the modern human face and vocal tract.
Asunto(s)
Metilación de ADN , ADN Antiguo , Cara/anatomía & histología , Fenotipo , Fonación/genética , Adulto , Anciano , Animales , Células Cultivadas , Niño , Condrocitos , Evolución Molecular , Femenino , Redes Reguladoras de Genes , Especiación Genética , Humanos , Laringe/anatomía & histología , Masculino , Persona de Mediana Edad , Hombre de Neandertal/genética , Pan troglodytes/genética , Cultivo Primario de Células , Lengua/anatomía & histología , Pliegues Vocales/anatomía & histología , Vocalización AnimalRESUMEN
Noxious mechanical information is transmitted through molecularly distinct nociceptors, with pinprick-evoked sharp sensitivity via A-fiber nociceptors marked by developmental expression of the neuropeptide Y receptor 2 (Npy2r) and von Frey filament-evoked punctate pressure information via unmyelinated C fiber nociceptors marked by MrgprD. However, the molecular programs controlling their development are only beginning to be understood. Here we demonstrate that Npy2r-expressing sensory neurons are in fact divided into two groups, based on transient or persistent Npy2r expression. Npy2r-transient neurons are myelinated, likely including A-fiber nociceptors, whereas Npy2r-persistent ones belong to unmyelinated pruriceptors that co-express Nppb. We then showed that the transcription factors NFIA and Runx1 are necessary for the development of Npy2r-transient A-fiber nociceptors and MrgprD+ C-fiber nociceptors, respectively. Behaviorally, mice with conditional knockout of Nfia, but not Runx1 showed a marked attenuation of pinprick-evoked nocifensive responses. Our studies therefore identify a transcription factor controlling the development of myelinated nociceptors.
Asunto(s)
Factores de Transcripción NFI , Nociceptores , Animales , Subunidad alfa 2 del Factor de Unión al Sitio Principal/fisiología , Femenino , Ganglios Espinales/fisiología , Masculino , Ratones , Ratones Noqueados , Factores de Transcripción NFI/fisiología , Fibras Nerviosas Amielínicas/fisiología , Nociceptores/fisiología , Receptores de Neuropéptido Y/fisiología , Células Receptoras Sensoriales/fisiologíaRESUMEN
Transcriptional regulation plays a central role in controlling neural stem and progenitor cell proliferation and differentiation during neurogenesis. For instance, transcription factors from the nuclear factor I (NFI) family have been shown to co-ordinate neural stem and progenitor cell differentiation within multiple regions of the embryonic nervous system, including the neocortex, hippocampus, spinal cord and cerebellum. Knockout of individual Nfi genes culminates in similar phenotypes, suggestive of common target genes for these transcription factors. However, whether or not the NFI family regulates common suites of genes remains poorly defined. Here, we use granule neuron precursors (GNPs) of the postnatal murine cerebellum as a model system to analyse regulatory targets of three members of the NFI family: NFIA, NFIB and NFIX. By integrating transcriptomic profiling (RNA-seq) of Nfia- and Nfix-deficient GNPs with epigenomic profiling (ChIP-seq against NFIA, NFIB and NFIX, and DNase I hypersensitivity assays), we reveal that these transcription factors share a large set of potential transcriptional targets, suggestive of complementary roles for these NFI family members in promoting neural development.
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Cerebelo/crecimiento & desarrollo , Cerebelo/metabolismo , Factores de Transcripción NFI/metabolismo , Animales , Animales Recién Nacidos , Cerebelo/citología , Secuenciación de Inmunoprecipitación de Cromatina/métodos , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factores de Transcripción NFI/genética , Neurogénesis/fisiología , EmbarazoRESUMEN
The nuclear factor one (NFI) site-specific DNA-binding proteins represent a family of transcription factors that are important for the development of multiple organ systems, including the brain. During brain development in mice, the expression patterns of Nfia, Nfib, and Nfix overlap, and knockout mice for each of these exhibit overlapping brain defects, including megalencephaly, dysgenesis of the corpus callosum, and enlarged ventricles, which implies a common but not redundant function in brain development. In line with these models, human phenotypes caused by haploinsufficiency of NFIA, NFIB, and NFIX display significant overlap, sharing neurodevelopmental deficits, macrocephaly, brain anomalies, and variable somatic overgrowth. Other anomalies may be present depending on the NFI gene involved. The possibility of variants in NFI genes should therefore be considered in individuals with intellectual disability and brain overgrowth, with individual NFI-related conditions being differentiated from one another by additional signs and symptoms. The exception is provided by specific NFIX variants that act in a dominant negative manner, as these cause a recognizable entity with more severe cognitive impairment and marked bone dysplasia, Marshall-Smith syndrome. NFIX duplications are associated with a phenotype opposite to that of haploinsufficiency, characterized by short stature, small head circumference, and delayed bone age. The spectrum of NFI-related disorders will likely be further expanded, as larger cohorts are assessed.
Asunto(s)
Crecimiento/genética , Mutación , Factores de Transcripción NFI/genética , Anomalías Múltiples/genética , Animales , Enfermedades del Desarrollo Óseo/genética , Anomalías Craneofaciales/genética , Duplicación de Gen , Trastornos del Crecimiento/genética , Humanos , Ratones , Displasia Septo-Óptica/genética , SíndromeRESUMEN
Precise temporal control of gene expression in neuronal progenitors is necessary for correct regulation of neurogenesis and cell fate specification. However, the cellular heterogeneity of the developing CNS has posed a major obstacle to identifying the gene regulatory networks that control these processes. To address this, we used single-cell RNA sequencing to profile ten developmental stages encompassing the full course of retinal neurogenesis. This allowed us to comprehensively characterize changes in gene expression that occur during initiation of neurogenesis, changes in developmental competence, and specification and differentiation of each major retinal cell type. We identify the NFI transcription factors (Nfia, Nfib, and Nfix) as selectively expressed in late retinal progenitor cells and show that they control bipolar interneuron and Müller glia cell fate specification and promote proliferative quiescence.
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Regulación del Desarrollo de la Expresión Génica/genética , Células-Madre Neurales/metabolismo , Neurogénesis/genética , Retina/embriología , Neuronas Retinianas/metabolismo , Animales , Proliferación Celular/genética , Células Ependimogliales/metabolismo , Interneuronas/metabolismo , Ratones , Mitosis/genética , Factores de Transcripción NFI/genética , RNA-Seq , Retina/crecimiento & desarrollo , Retina/metabolismo , Análisis de la Célula IndividualRESUMEN
BACKGROUND: Nuclear Factor One X (NFIX) haploinsufficiency in humans results in Malan syndrome, a disorder characterized by overgrowth, macrocephaly and intellectual disability. Although clinical assessments have determined the underlying symptomology of Malan syndrome, the fundamental mechanisms contributing to the enlarged head circumference and intellectual disability in these patients remains undefined. METHODS: Here, we used Nfix heterozygous mice as a model to investigate these aspects of Malan syndrome. Volumetric magnetic resonance imaging (MRI) was used to calculate the volumes of 20 brain sub regions. Diffusion tensor MRI was used to perform tractography-based analyses of the corpus callosum, hippocampal commissure, and anterior commissure, as well as structural connectome mapping of the whole brain. Immunohistochemistry examined the neocortical cellular populations. Two behavioral assays were performed, including the active place avoidance task to assess spatial navigation and learning and memory function, and the 3-chambered sociability task to examine social behaviour. FINDINGS: Adult Nfix+/- mice exhibit significantly increased brain volume (megalencephaly) compared to wildtypes, with the cerebral cortex showing the highest increase. Moreover, all three forebrain commissures, in particular the anterior commissure, revealed significantly reduced fractional anisotropy, axial and radial diffusivity, and tract density intensity. Structural connectome analyses revealed aberrant connectivity between many crucial brain regions. Finally, Nfix+/- mice exhibit behavioral deficits that model intellectual disability. INTERPRETATION: Collectively, these data provide a significant conceptual advance in our understanding of Malan syndrome by suggesting that megalencephaly underlies the enlarged head size of these patients, and that disrupted cortical connectivity may contribute to the intellectual disability these patients exhibit. FUND: Australian Research Council (ARC) Discovery Project Grants, ARC Fellowship, NYSTEM and Australian Postgraduate Fellowships.
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Corteza Cerebral/diagnóstico por imagen , Haploinsuficiencia , Discapacidad Intelectual/genética , Megalencefalia/genética , Factores de Transcripción NFI/genética , Animales , Conectoma , Modelos Animales de Enfermedad , Femenino , Humanos , Discapacidad Intelectual/diagnóstico por imagen , Discapacidad Intelectual/psicología , Imagen por Resonancia Magnética , Masculino , Megalencefalia/diagnóstico por imagen , Megalencefalia/psicología , Ratones , Tamaño de los Órganos , Aprendizaje EspacialRESUMEN
Understanding the migration of newborn neurons within the brain presents a major challenge in contemporary biology. Neuronal migration is widespread within the developing brain but is also important within the adult brain. For instance, stem cells within the ventricular-subventricular zone (V-SVZ) and the subgranular zone of dentate gyrus of the adult rodent brain produce neuroblasts that migrate to the olfactory bulb and granule cell layer of the dentate gyrus, respectively, where they regulate key brain functions including innate olfactory responses, learning, and memory. Critically, our understanding of the factors mediating neuroblast migration remains limited. The transcription factor nuclear factor I X (NFIX) has previously been implicated in embryonic cortical development. Here, we employed conditional ablation of Nfix from the adult mouse brain and demonstrated that the removal of this gene from either neural stem and progenitor cells, or neuroblasts, within the V-SVZ culminated in neuroblast migration defects. Mechanistically, we identified aberrant neuroblast branching, due in part to increased expression of the guanylyl cyclase natriuretic peptide receptor 2 (Npr2), as a factor contributing to abnormal migration in Nfix-deficient adult mice. Collectively, these data provide new insights into how neuroblast migration is regulated at a transcriptional level within the adult brain.
Asunto(s)
Movimiento Celular/genética , Giro Dentado/citología , Ventrículos Laterales/citología , Factores de Transcripción NFI/genética , Células-Madre Neurales/metabolismo , Animales , Regulación del Desarrollo de la Expresión Génica , Técnicas de Inactivación de Genes , Ratones , Células-Madre Neurales/citología , Neurogénesis/genética , Receptores del Factor Natriurético Atrial/genéticaRESUMEN
Cerebellar granule neurons are the most numerous neuronal subtype in the central nervous system. Within the developing cerebellum, these neurons are derived from a population of progenitor cells found within the external granule layer of the cerebellar anlage, namely the cerebellar granule neuron precursors (GNPs). The timely proliferation and differentiation of these precursor cells, which, in rodents occurs predominantly in the postnatal period, is tightly controlled to ensure the normal morphogenesis of the cerebellum. Despite this, our understanding of the factors mediating how GNP differentiation is controlled remains limited. Here, we reveal that the transcription factor nuclear factor I X (NFIX) plays an important role in this process. Mice lacking Nfix exhibit reduced numbers of GNPs during early postnatal development, but elevated numbers of these cells at postnatal day 15. Moreover, Nfix-/- GNPs exhibit increased proliferation when cultured in vitro, suggestive of a role for NFIX in promoting GNP differentiation. At a mechanistic level, profiling analyses using both ChIP-seq and RNA-seq identified the actin-associated factor intersectin 1 as a downstream target of NFIX during cerebellar development. In support of this, mice lacking intersectin 1 also displayed delayed GNP differentiation. Collectively, these findings highlight a key role for NFIX and intersectin 1 in the regulation of cerebellar development.
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Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Proliferación Celular/fisiología , Cerebelo/citología , Factores de Transcripción NFI/metabolismo , Células-Madre Neurales/citología , Neuronas/citología , Proteínas Adaptadoras del Transporte Vesicular/genética , Animales , Cerebelo/crecimiento & desarrollo , Cerebelo/metabolismo , Regulación del Desarrollo de la Expresión Génica , Ratones Noqueados , Factores de Transcripción NFI/genética , Células-Madre Neurales/metabolismo , Neurogénesis/fisiología , Neuronas/metabolismoRESUMEN
The nuclear factor I (NFI) family of transcription factors play an important role in normal development of multiple organs. Three NFI family members are highly expressed in the brain, and deletions or sequence variants in two of these, NFIA and NFIX, have been associated with intellectual disability (ID) and brain malformations. NFIB, however, has not previously been implicated in human disease. Here, we present a cohort of 18 individuals with mild ID and behavioral issues who are haploinsufficient for NFIB. Ten individuals harbored overlapping microdeletions of the chromosomal 9p23-p22.2 region, ranging in size from 225 kb to 4.3 Mb. Five additional subjects had point sequence variations creating a premature termination codon, and three subjects harbored single-nucleotide variations resulting in an inactive protein as determined using an in vitro reporter assay. All individuals presented with additional variable neurodevelopmental phenotypes, including muscular hypotonia, motor and speech delay, attention deficit disorder, autism spectrum disorder, and behavioral abnormalities. While structural brain anomalies, including dysgenesis of corpus callosum, were variable, individuals most frequently presented with macrocephaly. To determine whether macrocephaly could be a functional consequence of NFIB disruption, we analyzed a cortex-specific Nfib conditional knockout mouse model, which is postnatally viable. Utilizing magnetic resonance imaging and histology, we demonstrate that Nfib conditional knockout mice have enlargement of the cerebral cortex but preservation of overall brain structure and interhemispheric connectivity. Based on our findings, we propose that haploinsufficiency of NFIB causes ID with macrocephaly.
Asunto(s)
Haploinsuficiencia/genética , Discapacidad Intelectual/genética , Megalencefalia/genética , Factores de Transcripción NFI/genética , Adolescente , Adulto , Animales , Corteza Cerebral/patología , Niño , Preescolar , Codón sin Sentido/genética , Estudios de Cohortes , Cuerpo Calloso/patología , Femenino , Humanos , Masculino , Ratones , Ratones Noqueados , Polimorfismo de Nucleótido Simple/genética , Adulto JovenRESUMEN
OBJECTIVE: The active place avoidance task (APA) is a behavioural task used to assess learning and memory in rodents. This task relies on the hippocampus, a region of the cerebral cortex capable of generating new neurons from neural stem cells. In this study, to gain further insight into the behavioural phenotype of mice deficient in the transcription factor Nfix, a gene expressed by adult neural stem cells, we examined learning and memory parameters from the APA task that were not published in our original investigation. We analysed time to first and second shock, maximum path and time of shock avoidance, number of entries into the shock zone and time spent in the shock zone. We also assessed performance in the APA task based on sex. RESULTS: We found mice deficient in Nfix displayed decreased latency to second shock compared to the control mice. Nfix deficient mice entered the shock zone more frequently and also spent more time in the shock zone. Our data provides further insights into the memory deficits evident in Nfix mutant mice, indicating these mice have a memory retrieval problem and may employ a different navigation strategy in the APA task.
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Hipocampo/fisiología , Aprendizaje , Memoria , Factores de Transcripción NFI/genética , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Células-Madre NeuralesRESUMEN
BACKGROUND: Radial glial stem cells within the developing nervous system generate a variety of post-mitotic cells, including neurons and glial cells, as well as the specialised multi-ciliated cells that line the walls of the ventricular system, the ependymal cells. Ependymal cells separate the brain parenchyma from the cerebrospinal fluid and mediate osmotic regulation, the flow of cerebrospinal fluid, and the subsequent dispersion of signalling molecules via the co-ordinated beating of their cilia. Deficits to ependymal cell development and function have been implicated in the formation of hydrocephalus, but the transcriptional mechanisms underpinning ependymal development remain poorly characterised. FINDINGS: Here, we demonstrate that the transcription factor nuclear factor IX (NFIX) plays a central role in the development of the ependymal cell layer of the lateral ventricles. Expression of ependymal cell-specific markers is delayed in the absence of Nfix. Moreover, Nfix-deficient mice exhibit aberrant ependymal cell morphology at postnatal day 15, culminating in abnormal thickening and intermittent loss of this cell layer. Finally, we reveal Foxj1, a key factor promoting ependymal cell maturation, as a target for NFIX-mediated transcriptional activation. CONCLUSIONS: Collectively, our data indicate that ependymal cell development is reliant, at least in part, on NFIX expression, further implicating this transcription factor as a mediator of multiple aspects of radial glial biology during corticogenesis.
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Encéfalo/anatomía & histología , Encéfalo/crecimiento & desarrollo , Epéndimo/citología , Neuroglía/metabolismo , Factores de Transcripción/metabolismo , Factores de Edad , Análisis de Varianza , Animales , Animales Recién Nacidos , Cadherinas/metabolismo , Inmunoprecipitación de Cromatina , Factores de Transcripción Forkhead/metabolismo , Regulación del Desarrollo de la Expresión Génica/genética , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microscopía Confocal , Factores de Transcripción NFI/genética , Factores de Transcripción NFI/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Factores de Transcripción/genéticaRESUMEN
We show that BDNF regulates the timing of neurodevelopment via a novel mechanism of extranuclear sequestration of NFATc4 in Golgi. This leads to accelerated derepression of an NFI temporal occupancy gene program in cerebellar granule cells that includes Bdnf itself, revealing an autoregulatory loop within the program driven by BDNF and NFATc4.