Project description:The specification of the different neuronal subtypes is associated with a profound morphological transformation, involving processes common to most neurons and others characteristic of each neuronal subtype. To study the Tcf-dependent genes that were active during commissural neuron differentiation, we compared the genes in differentiating neurons (Tubb3+ cells) after the repression of Tcf-dependet transcription in chichen neural tube from E3 to E4, period when mostly commissural neurons are differentiating. We used Affymetrix GeneChip arrays to study TCF regulated genes during this process.
Project description:At an incidence of approximately 1/1000 births, neural tube defects (NTDs) comprise one of the most common and devastating congenital disorders. In an attempt to enhance and expand our understanding of neural tube closure, we undertook a high-throughput gene expression analysis of the neural tube as it was forming in the mouse embryo. Open and closed sections of the developing neural tube were micro-dissected from mouse embryos, and hybridized to Affymetrix mouse expression arrays. Clustering of genes differentially regulated in open and closed sections of the developing neural tube highlighted molecular processes previously recognized to be involved in neural tube closure and neurogenesis. Analysis of the genes in these categories identified potential candidates underlying neural tube closure. In addition, we identified approximately 25 novel genes, of unknown function, that were significantly up-regulated in the closed neural tube. Based on their expression patterns in the developing neural tube, five novel genes are proposed as interesting candidates for involvement in neurogenesis. The high-throughput expression analysis of the neural tube as it forms allows for better characterization of pathways involved in neural tube closure and neurogenesis, and hopefully will strengthen the foundation for further research along the pathways dictating neural tube development.
Project description:At an incidence of approximately 1/1000 births, neural tube defects (NTDs) comprise one of the most common and devastating congenital disorders. In an attempt to enhance and expand our understanding of neural tube closure, we undertook a high-throughput gene expression analysis of the neural tube as it was forming in the mouse embryo. Open and closed sections of the developing neural tube were micro-dissected from mouse embryos, and hybridized to Affymetrix mouse expression arrays. Clustering of genes differentially regulated in open and closed sections of the developing neural tube highlighted molecular processes previously recognized to be involved in neural tube closure and neurogenesis. Analysis of the genes in these categories identified potential candidates underlying neural tube closure. In addition, we identified approximately 25 novel genes, of unknown function, that were significantly up-regulated in the closed neural tube. Based on their expression patterns in the developing neural tube, five novel genes are proposed as interesting candidates for involvement in neurogenesis. The high-throughput expression analysis of the neural tube as it forms allows for better characterization of pathways involved in neural tube closure and neurogenesis, and hopefully will strengthen the foundation for further research along the pathways dictating neural tube development. Embryos were dissected at days E8.5 and E9.5, and the neuroepithelium/ neural tube were mechanically detached from underlying tissues, and then separated into two regions: 1) M-bM-^@M-^\open neuroepitheliumM-bM-^@M-^]: neuroepithelial tissue caudal to the open/closed junction, and 2) M-bM-^@M-^\closed neural tubeM-bM-^@M-^], extending from a somiteM-bM-^@M-^Ys breadth rostral to the open/closed junction, up to the level of the fifth- or sixth-to-last somite. Samples consisted of biological triplicates of RNA extract from the above tissues (pooled by litter, and representing a total of 111 embryos): E8.5 open neuroepithelium, E8.5 closed neural tube, E9.5 open neuroepithelium, and E9.5 closed neural tube. Thus, a total of 12 samples (representing 111 embryos) were hybridized to the GeneChip Mouse Genome 430 2.0 Array (Affymetrix Inc., Santa Clara, CA, USA). One of the samples (06, closed E8.5) deviated significantly from the others in quality assessment and was therefore removed from subsequent analysis and not submitted to GEO.
Project description:We analyzed scRNA-seq data in human pluripotent stem cells derived neural tube models. This in vitro system recapitulates some key aspects of neural patterning in the entire neural tube, including both brain and SC regions, along both rostral-caudal and dorsal-ventral axes
Project description:Maternal diabetes is a teratogen that can lead to neural tube closure defects in the offspring. We therefore sought to compare gene expression profiles at the site of neural tube closure between stage-matched embryos from normal dams, and embryos from diabetic dams. Neurulation-stage mouse embryos at 8.5 days of gestation were used to prepare neural tissue at the anterior aspect of neural tube closure site 1. Tissue was procured from the open neural tube immediately anterior of the closure site, and from the closed neural tube immediately posterior to the closure site by laser microdissection. For each sample, 10 sections were pooled, total RNA was extracted, and 7 ng of total RNA were used for expression profiling by Tag sequencing using an Applied Biosystems SolidSAGE kit for library construction, and an AB SOLiD 5500 XL instrument for sequencing. Sequence reads were mapped to RefSeq RNA, and count data per gene were obtained using a modified version of the Applied Biosystems SOLiDâ?¢ SAGEâ?¢ Analysis Software. diabetic dam - closed neural tube // diabetic dam - open neural tube // normal dam - closed neural tube // normal dam - open neural tube
Project description:BACKGROUND: Development of the neural tube is a highly orchestrated process relying on precise, spatio-temporal expression of numerous genes as well as hierarchies of signal transduction and gene regulatory networks. Disruption of expression of a number of genes participating in these networks is believed to underlie developmental anomalies such as neural tube defects (NTDs) resulting from anomalous neural tube morphogenesis. MicroRNAs (miRNAs), a large family of noncoding RNAs, have been shown to function as gene silencers, and thus, are key modulators of cell and tissue differentiation. To elucidate potential roles of miRNAs in murine neural tube development, miRNA gene expression profiling has been utilized in the current study, to garner novel and in-depth knowledge on the expression and regulation of genes encoding miRNAs as well as their potential target genes governing maturation of the mammalian neural tube. METHODS: With the aim of identifying differentially expressed miRNAs during mammalian neural tube ontogenesis, miRNA expression profiles from gestation day (GD) -8.5, -9.0 and -9.5 murine neural tube tissue were compared utilizing miRXplore™ microarrays from Miltenyi Biotech GmbH. Gene expression changes observed in microarray analysis were verified by TaqManTM quantitative Real-Time PCR. clValid R package and the UPGMA (hierarchical) clustering method were utilized for cluster analysis of the microarray data. Functional associations among selected miRNAs were examined exploiting Ingenuity Pathway Analysis. RESULTS: Expression of approximately 12% of the 609 murine miRNA genes examined was detected in murine neural tube tissues from GD -8.5, -9.0 and -9.5. Clustering analysis revealed several developmentally regulated clusters among these expressed genes. MicroRNA target analysis enabled identification of a panoply of protein-coding target genes of the differentially expressed miRNAs within such clusters. Interestingly, many of these target genes have been shown to be associated with vital cellular processes such as cell proliferation, cell adhesion, cell migration, differentiation, apoptosis and epithelial-mesenchymal transformation, all of which are essential for normal neural tube development. Utilization of Ingenuity Pathway Analysis (IPA; Ingenuity Systems) allowed identification of interactive biological networks connecting differentially expressed miRNAs and their target genes highlighting functional relationships. CONCLUSIONS: In the present study, a unique gene expression signature of a range of miRNAs in embryonic neural tube tissue was delineated. Analysis of miRNA target genes and gene interaction pathways emphasized that expression of numerous protein-encoding genes, indispensable for normal neural tube morphogenesis, may be regulated by specific miRNAs.
Project description:The process of neural tube closure is a highly complex morphogenetic event that results in the generation of the primordial central nervous system. During formation of the neural tube, the non-neural ectoderm separates from the neighboring neural ectoderm and forms a single layer epithelial sheet that overlies the closed neural tube. Previous work has shown that the non-neural ectoderm is necessary for proper cranial neural tube closure, however little is known about this cell population at the molecular level or how the non-neural ectoderm contributes to neural tube closure. In this study, we used a mouse genetic system to fluorescently label the non-neural ectoderm cells and FACS sorted these cells away from the other cell populations in the neural tube. We performed high throughput RNA-sequencing to identify the transcriptome of the non-neural ectoderm and compared the gene expression profile of non-neural ectoderm cells to the remaining population of cells within the neural tube in order to identify which genes are enriched within the non-neural ectoderm. This analysis provides a clue as to which underlying molecular processes may be important for non-neural ectoderm function during neural tube closure.
Project description:This data series was used for two separate studies. The initial study was aimed to idenify expression changes brought about by the Cecr2Gt45Bic mutation during neural closure. The study included two different strains, BALB/cCrl in which Cecr2GT45Bic shows a neural tube defect phenotype and FVB/N in which Cecr2Gt45Bic does not manifest neural closure defects. The second was to idenify strain specific expression differences present during neural closure of the mouse embryo between BALB/cCrl and FVB/N in order to identify candidate modifiers of the Cecr2Gt45Bic neural tube defect. Relevant abstracts are included below. The initial study ; BACKGROUND: Over 200 mouse genes are associated with neural tube defects (NTDs), including Cecr2, the bromodomain-containing subunit of the CERF chromatin remodeling complex. METHODS: Gene-trap mutation Cecr2Gt45Bic results in 74% exencephaly (equivalent of human anencephaly) on the BALB/c strain. Gene expression altered during cranial neural tube closure by the Cecr2 mutation was identified through microarray analysis of 11–14 somites stage Cecr2Gt45Bicembryos. RESULTS: Analysis of Affymetrix Mouse 430 2.0 chips detected 60 transcripts up-regulated and 54 transcripts down-regulated in the Cecr2Gt45Bic embryos (fold > 1.5, p < 0.05). The Cecr2 transcript was reduced only ∼7- to 14-fold from normal levels, suggesting the Cecr2Gt45Bic is a hypomorphic mutation. We therefore generated a novel Cecr2 null allele (Cecr2tm1.1Hemc). Resulting mutants displayed a stronger penetrance of exencephaly than Cecr2Gt45Bic in both BALB/c and FVB/N strains, in addition to midline facial clefts and forebrain encephalocele in the FVB/N strain. The Cecr2 transcript is reduced 260-fold in the Cecr2tm1.1Hemc line. Subsequent qRT-PCR using Cecr2tm1.1Hemc mutant heads confirmed downregulation of transcription factors Alx1/Cart1,Dlx5, Eya1, and Six1. CONCLUSIONS: As both Alx1/Cart1 and Dlx5 mouse mutations result in exencephaly, we hypothesize that changes in expression of these mesenchymal/ectodermal transcription factors may contribute to NTDs associated with Cecr2. Birth Defects Research (Part A), 2010. 010 Wiley-Liss, Inc. The second study: ABSTRACT:Although neural tube defects (NTDs) are common in humans, little is known about their multifactorial genetic causes. While most mouse models involve NTDs caused by a single mutated gene, we have previously described a multigenic system involving susceptibility to NTDs. In mice with a mutation in Cecr2, the cranial NTD exencephaly shows strain specific differences in penetrance, with 74% penetrance in BALB/cCrl and 0% penetrance in FVB/N. Whole genome linkage analysis showed that a region of chromosome 19 was partially responsible for this difference in penetrance. We now reveal by genetic analysis of three subinterval congenic lines that the chromosome 19 region contains more than one modifier gene. Analysis of embryos showed that although a Cecr2 mutation causes wider neural tubes in both strains, FVB/N embryos overcome this abnormality and close. A microarray analysis comparing neurulating female embryos from both strains identified differentially expressed genes within the chromosome 19 region, including Arhgap19, which is expressed at a lower level in BALB/cCrl due to a stop codon specific to that substrain. Modifier genes in this region are of particular interest because it is syntenic to human chromosome 10q25, the site of a human susceptibility locus. (MANUSCRIPT PENDING SUBMISSION)