ABSTRACT: Identification of transcriptome of mouse non-neural ectoderm during nueral tube closure and gene enrichment compared to remaining neural tube tissue
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:During primary neurulation, the separation of a single-layered ectodermal sheet into the surface ectoderm (SE) and neural tube specifies SE and neural ectoderm (NE) cell fates. The mechanisms underlying fate specification in conjunction with neural tube closure are poorly understood. Here, by comparing expression profiles between SE and NE lineages, we observed that uncommitted progenitor cells, expressing stem cell markers, are present in the neural plate border/neural fold prior to neural tube closure.
Project description:During primary neurulation, the separation of a single-layered ectodermal sheet into the surface ectoderm (SE) and neural tube specifies SE and neural ectoderm (NE) cell fates. The mechanisms underlying fate specification in conjunction with neural tube closure are poorly understood. Here, by comparing expression profiles between SE and NE lineages, we observed that uncommitted progenitor cells, expressing stem cell markers, are present in the neural plate border/neural fold prior to neural tube closure. To identify what type of signaling pathways and transcriptional factors are involved in the fate specification between SE and NE cells during neurulation.
Project description:Neural tube closure in vertebrates is achieved through a highly dynamic and coordinated series of morphogenic events involving neural plate, surface ectoderm, and neural plate border. Failure of this process in the caudal region causes spina bifida. Grainyhead-like 3 (GRHL3) is an indispensable transcription factor for neural tube closure as constitutive inactivation of which leads to fully penetrant spina bifida. Here, through single-cell transcriptomics we show that at E8.5, the time-point preceding mouse neural tube closure, the co-expression of Grhl3, Tfap2a, and Tfap2c defines a previously unrecognised progenitor population of surface ectoderm. Specific deletion of Grhl3 expression using Tfap2a-Cre recapitulate the spina bifida observed in Grhl3-null animals. Moreover, conditional inactivation of Tfap2c expression in Grhl3-expressing neural plate border cells also causes mild spina bifida. These findings clearly indicate that Grhl3-expressing neural plate border cells cohort is required for the early-stage neurulation.
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:Maternal diabetes is a teratogen that can lead to neural tube closure defects in the offspring. In neurulation-stage embryos from diabetic dams, we detected abnormal tissue protruding from the open neural tube. To determine the origin of such protrusions, we compared gene expression profiles between open neural plate with normal morphology, and protrusion tissue. Neurulation-stage mouse embryos at 8.5 days of gestation were used to prepare open neural tube at the anterior aspect of neural tube closure site 1 by laser capture 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. Protrusion tissue was prepared from whole embryos by microdissection, and 12ng of total RNA per sample was used for Tag sequencing. Sequence reads were mapped to RefSeq RNA, and count data per gene were obtained using a modified version of the Applied Biosystems SOLiD⢠SAGE⢠Analysis Software. Neural plate protrusion compared to open neural plate anterior of closure site 1 with normal morphology
Project description:Purpose: Identify genes and pathways affected in tuft embryos with NTDs Results: Expression of genes associated with neural tube closure and components of non-canonical WNT signaling/PCP pathways were affected Conclusions: TET1 regulates genes associated with neural tube closure
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 SOLiD™ SAGE™ Analysis Software.
Project description:single-cell sequencing of the mouse cranial region at E8.25 (the start of neural tube closure, at E9.5 (the end of neural tube closure, and of a miR-302 knockout embryo at E9.5 (example of neural tube closure defrect).