ABSTRACT: intermediate region of the posterior neural plate from HH stage 9+ embryos were cultured for 0hours or for 12 hours with the control or FGF containing medium
Project description:The neural crest (NC) is a transient dynamic structure of ectodermal origin, found in early vertebrate embryos. The multipotential NC cells migrate along well defined routes, differentiate to various cells types including melanocytes and participate in the formation of various permanent tissues. Abnormal development of NC cells causes several human diseases M-bM-^@M-^S neurocristopathies. As there is only limited information about the molecular mechanisms controlling early events in melanocyte specification and development, we exploited the AMV v-Myb transcriptional regulator, which directs differentiation of in vitro chicken NC cells to the melanocyte lineage. This activity is strictly dependent on v-Myb specifically binding to the Myb recognition DNA element (MRE). The two tamoxifen-inducible v-myb alleles were constructed, one which recognizes the MRE and one which does not. These were activated in ex-ovo NC cells, and the expression profiles of resulting cells were analyzed using Affymetrix microarrays and RT-PCR. These approaches revealed up-regulation of the BMP antagonist gremlin 2 mRNA, and down-regulation of mRNAs encoding several epithelial genes including KRT19 as very early events following the activation of melanocyte differentiation by v-Myb. Comparison of gene expression profiles of chicken neural crest cells constitutively expressing 4-OH-tamoxifen inducible v-myb with mutated leucine zipper region or a version with an additional point mutation (N118D) in the DNA-binding domain. Three biological replicates were analyzed for each group.
Project description:The proneural NEUROG2 is essential for neuronal commitment, cell cycle exit and neuronal differentiation. Characterizing genes networks regulated downstream of NEUROG2 is therefore of prime importance. To identify NEUROG2 early response genes, we combined gain of function in the neural tube with a global detection of modified transcripts using microarrays. We included in our study a mutant form of NEUROG2 (NEUROG2AQ) that cannot bind DNA and cannot trigger neurogenesis. Using this approach, we identified 942 genes modified at the onset of NEUROG2 activation. The global analysis of functions regulated by NEUROG2 allowed unmasking its rapid impact on cell cycle control. We found that NEUROG2 specifically represses a subset of cyclins acting at the G1 and S phases of the cell cycle, thereby impeding S phase re-entry. This repression occurs before modification of p27kip1, indicating that the decision to leave the cell cycle precedes the activation of this Cyclin-dependant Kinase Inhibitor. Moreover, NEUROG2 down-regulates only one of the D-type cyclins, cyclinD1, and maintaining cyclinD1 blocks the ability of the proneural to trigger cell cycle exit, without altering its capacity to trigger neuronal differentiation. The fact that NEUROG2 represses a subset but not all cell cycle regulators indicates that cell cycle exit is not an indirect consequence of neuronal differentiation but is precisely controlled by NEUROG2. Altogether our findings indicate that NEUROG2, by specifically repressing G1 and S cyclins, allows committed neuronal precursors to perform their last mitosis but blocks their re-entry in the cell cycle, thus favouring cell cycle exit. Stage HH10-11 embryos (11 to 15 somites) were electroporated with a control vector (pGIG-GFP), a NEUROG2-expressing vector (pCIGNEUROG2-GFP), or a NEUROG2AQ-expressing vector (pCIGNEUROG2AQ-GFP). For each biological replicate, neural tubes from 20 embryos were pooled for GFP+ cells collection. GFP+ cells were collected 6h later using FACS sorting (Epics Altra HSS cell sorter, Toulouse Rio platform) and processed for RNA probe preparation and hybridization on Affymetrix microarrays. For each experimental condition, four biological replicates were processed.
Project description:Combining an in vitro hNCC differentiation protocol with epigenomic profiling, we provide the first whole-genome characterization of cis-regulatory elements in this highly relevant cell type. With this data at hand, we have characterized the chromatin state and dynamics of all human gene promoters during the course of NCC in vitro differentiation. Most importantly, we have identified a large cohort of active and NCC-specific enhancers, which we showed to be functionally relevant in vivo, in the context of embryonic development. Finally, through sequence analysis of the identified NCC enhancers, we uncovered the orphan nuclear receptors NR2F1 and NR2F2 as novel hNCC transcriptional regulators both in vitro and in vivo. Genome-wide analysis of H3K27ac in chicken neural crest cells (NCC) obtained from stage 11-14 or stage 20 embryos
Project description:Purified hair bundles and utricular epithelium from E19-E20 chick inner ears were analyzed by LC-MS/MS to determine the abundant and enriched proteins of the hair bundle. This dataset used a Thermo LTQ mass spectrometer for protein detection.
Project description:Purified hair bundles and utricular epithelium from E19-E20 chick inner ears were analyzed by LC-MS/MS to determine the abundant and enriched proteins of the hair bundle. This dataset used a Thermo LTQ Velos mass spectrometer for protein detection.
Project description:This is a reanalysis of PXD000104. Purified hair bundles and utricular epithelium from E19-E20 chick inner ears were analyzed by LC-MS/MS to determine the abundant and enriched proteins of the hair bundle. This dataset used a Thermo Orbitrap Elite mass spectrometer for protein detection.
Project description:Microarray analysis of chick embryo tissues: Hamburger Hamilton (HH) stage 3+/4 and HH6 Hensenâs node, HH 3+/4 posterior primitive streak, notochord with ventral neural tube at HH10-11, dorsal neural tube at HH10-11 and anterior and posterior thirds of the wing bud at stages HH20-21 and HH24.
Project description:The spinal cord is generated progressively as cells leave the caudal region of the elongating body axis such that the temporal steps of neural differentiation become spatially separated along the head to tail axis. At key stages, it is therefore possible to isolate near-adjacent cell populations from the same embryo in distinct differentiation states. Cells in the caudal lateral epiblast adjacent to the primitive streak (also known as the stem zone, SZ, in the chick) express both early neural and mesodermal genes. Other cells in the stem zone will gastrulate to form the paraxial mesoderm or remain in the epiblast cell sheet and become neural progenitors. These latter cells form a new region called the preneural tube (PNT), which is flanked by unsegmented presomitic mesoderm and represents an early neural progenitor state that can be induced by FGF signalling to revert back to a multi-potent SZ state. Rostral to this, the closed caudal neural tube (CNT) is flanked by somites and is an early site of co-expression of genes characteristic of neural progenitors, and of ventral patterning genes (Diez del Corral et al., 2003). The CNT contains the first few neurons and exposure to FGF cannot revert this tissue to a multi-potent SZ state (Diez del Corral et al., 2002). The transition from the PNT to the CNT thus involves commitment to a neural fate that this is regulated by a switch from FGF to retinoid signalling. More advanced neuroepithelium is then located in more rostral neural tube (RNT), in which neuronal differentiation is ongoing and dorsoventral pattern is refined. This experiment uses the Affymetrix GeneChip chicken genome microarray to compare the transcriptomes of microdissections of these spatially distinct cell populations from the elongating neural axis of HH stage 10 chick embryos. Dissections were carried out in L15 medium at 4°C and explants pooled in TRIzol reagent (Gibco) for RNA extraction. Notochord was removed by controlled trypsin digestion that aimed to keep the neural ventral midline. For the microarrays, at least five tissue samples for each region were pooled to make each of three biological replicates for each (n>15 for each region).