Transcription profiling of mouse presomitic mesoderm and somite-level tissue of 9.5 dpc Dll3 mutants
Ontology highlight
ABSTRACT: This SuperSeries is composed of the following subset Series:; GSE15152: MOE430A Analysis of Dll3 mutant vs. wild-type 9.5 dpc presomitic mesoderm; GSE15153: MOE430A Analysis of Dll3 mutant vs. wild-type 9.5 dpc somite-level tissue Experiment Overall Design: Refer to individual Series
Project description:Delta-like 3 (Dll3) is a divergent ligand and modulator of the Notch signaling pathway only identified so far in mammals. Null mutations of Dll3 disrupt cycling expression of Notch targets Hes1, Hes5, and Lfng, but not of Hes7. Compared with Dll1 or Notch1, the effects of Dll3 mutations are less severe for gene expression in the presomitic mesoderm, yet severe segmentation phenotypes and vertebral defects result in both human and mouse. Reasoning that Dll3 specifically disrupts key regulators of somite cycling, we carried out functional analysis to identify targets accounting for the segmental phenotype. Using microdissected embryonic tissue from somitic and presomitic mesodermal tissue, we identified new genes enriched in these tissues, including Limch1, Rphn2, and A130022J15Rik. Surprisingly, we only identified a small number of genes disrupted by the Dll3 mutation. These include Uncx, a somite gene required for rib and vertebral patterning, and Nrarp, a regulator of Notch/Wnt signaling in zebrafish and a cycling gene in mouse. To determine the effects of Dll3 mutation on Nrarp, we characterized the cycling expression of this gene from early (8.5 dpc) to late (10.5 dpc) somitogenesis. Nrarp displays a distinct pattern of cycling phases when compared to Lfng and Axin2 (a Wnt pathway gene) at 9.5 dpc but appears to be in phase with Lfng by 10.5 dpc. Nrarp cycling appears to require Dll3 but not Lfng modulation. In Dll3 null embryos, Nrarp displayed static patterns. However, in Lfng null embryos, Nrarp appeared static at 8.5 dpc but resumed cycling expression by 9.5 and dynamic expression at 10.5 dpc stages. By contrast, in Wnt3a null embryos, Nrarp expression was completely absent in the presomitic mesoderm. Towards identifying the role of Dll3 in regulating somitogenesis, Nrarp emerges as a potentially important regulator that requires Dll3 but not Lfng for normal function. Experiment Overall Design: To enrich for genes in the presomitic mesoderm that are specifically disrupted by Dll3 mutation, we compared microdissected tissues from wild-type and Dll3 mutant embryos. We generated biological replicate pools from Dll3+/+ (wild-type) or Dll3neo/neo embryos for a total of six pools. Microarray analysis using Affymetrix MOE430A arrays was carried out on the biological pool triplicates for both wild-type and mutant genotypes.
Project description:Delta-like 3 (Dll3) is a divergent ligand and modulator of the Notch signaling pathway only identified so far in mammals. Null mutations of Dll3 disrupt cycling expression of Notch targets Hes1, Hes5, and Lfng, but not of Hes7. Compared with Dll1 or Notch1, the effects of Dll3 mutations are less severe for gene expression in the presomitic mesoderm, yet severe segmentation phenotypes and vertebral defects result in both human and mouse. Reasoning that Dll3 specifically disrupts key regulators of somite cycling, we carried out functional analysis to identify targets accounting for the segmental phenotype. Using microdissected embryonic tissue from somitic and presomitic mesodermal tissue, we identified new genes enriched in these tissues, including Limch1, Rphn2, and A130022J15Rik. Surprisingly, we only identified a small number of genes disrupted by the Dll3 mutation. These include Uncx, a somite gene required for rib and vertebral patterning, and Nrarp, a; regulator of Notch/Wnt signaling in zebrafish and a cycling gene in mouse. To determine the effects of Dll3 mutation on Nrarp, we characterized the cycling expression of this gene from early (8.5 dpc) to late (10.5 dpc) somitogenesis. Nrarp displays a distinct pattern of cycling phases when compared to Lfng and Axin2 (a Wnt pathway gene) at 9.5 dpc but appears to be in phase with Lfng by 10.5 dpc. Nrarp cycling appears to require Dll3 but not Lfng modulation. In Dll3 null embryos, Nrarp displayed static patterns. However, in Lfng null embryos, Nrarp appeared static at 8.5 dpc but resumed cycling expression by 9.5 and dynamic expression at 10.5 dpc stages. By contrast, in Wnt3a null embryos, Nrarp expression was completely absent in the presomitic mesoderm. Towards identifying the role of Dll3 in regulating somitogenesis, Nrarp emerges as a potentially important regulator that requires Dll3 but not Lfng for normal function. Experiment Overall Design: To enrich for genes in the somite level tissues that are specifically disrupted by Dll3 mutation, we compared microdissected tissues from wild-type and Dll3 mutant embryos. We generated biological replicate pools from Dll3+/+ (wild-type) or Dll3neo/neo embryos for a total of six pools. Microarray analysis using Affymetrix MOE430A arrays was carried out on the biological pool triplicates for both wild-type and mutant genotypes.
Project description:Decrease in Cdx dosage in an allelic series of mouse Cdx mutants leads to progressively more severe posterior vertebral defects. These defects are corrected by posterior gain of function of the Wnt effector Lef1. Precocious expression of Hox paralogous 13 genes also induces vertebral axis truncation by antagonizing Cdx function. We report here that the phenotypic similarity also applies to patterning of the caudal neural tube and uro-rectal tracts in Cdx and Wnt3a mutants, and in embryos precociously expressing Hox13 genes. Cdx2 inactivation after placentation leads to posterior defects including incomplete uro-rectal septation. Compound mutants carrying one active Cdx2 allele in the Cdx4 null background (Cdx2/4), transgenic embryos precociously expressing Hox13 genes, and a novel Wnt3a hypomorph mutant all manifest a comparable phenotype with similar urorectal defects. Phenotype and transcriptome analysis in early Cdx mutants, genetic rescue experiments and gene expression studies lead us to propose that Cdx transcription factors act via Wnt signalling during the laying down of urorectal mesoderm, and that they are operative in an early phase of these events, at the site of tissue progenitors in the posterior growth zone of the embryo. Cdx and Wnt mutations and premature Hox13 expression also cause similar neural dysmorphology including ectopic neural structures sometimes leading to neural tube splitting at caudal axial levels. These findings involve the Cdx genes, canonical Wnt signalling, and the temporal control of posterior Hox gene expression in posterior morphogenesis in the different embryonic germ layers. They shed a new light on the etiology of the Caudal Dysplasia or Caudal Regression range of human congenital defects. We used dissected Cdx2 null mutant versus wild type embryos at the 4/5 somite and 7/8 somite stage. RNA was isolated from the posterior part of the embryos (20 embryos of each genotype and stage), dissected at the same axial levels by using the last somite boundary and the base of the allantois as landmarks. Differentially labelled cRNA from the Cdx2 and control embryos were hybridized on 4X44K Agilent Whole Mouse Genome dual colour Microarrays (G4122F) in two dye swap experiments and two technical replicates, resulting in eight individual arrays.
Project description:Using a combination of cell sorting and microarray analysis, we identified almost 200 genes as having a high level of expression in the notochord. After whole mount in situ hybridization screening, we confirmed approximately one third of these as having a novel notochord expression pattern. Keywords: cell type comparison - embryonic Noto-GFP+ notochord progenitors versus surrounding GFP- comparator cells 3 biological replicates - each replicate includes an experiment cell population (Noto-GFP positive cell sort) and a comparator population (GFP negative cell sort)
Project description:4 microarray time series was generated to identify cyclic genes of the segmentation clock in the mouse (2 time series), the chicken and the zebrafish. The right posterior half presomitic mesoderms (PSM) from 20 mouse embryos, 18 chicken embryos and 21 zebrafish embryos were dissected while the contralateral side of the embryo containing the left PSM was immediately fixed to be analyzed by in situ hybridization using a Lfng (fot mosue and chicken) or hes7 (zebrafish) probe to order the samples along the segmentation clock oscillation cycle. Probes were produced from RNA extracted from each of the dissected posterior half PSMs using a two-step amplification protocol and were hybridized to Affymetrix GeneChip MOE430A, MOE430 2.0, Affymetrix GeneChip chicken genome array, or Affymetrix GeneChip zebrafish array.
Project description:The effects of loss of the large neutral amino acid transporter Slc7a5 (aka Lat1) on mouse embryonic development were investigated. Slc7a5 fl/fl mice harbouring two copies of the Slc7a5 targeted allele (exon 1 of Slc7a5 flanked with two loxP sites), were crossed with a mouse line ubiquitously expressing cre recombinase under the Bal1 promoter (Bal1-cre) to obtain a global Slc7a5 knockout mouse (Poncet et al. 2014 PLoS One 9: e89547). Heterozygous Slc7a5+/- C57Bl/6 mice were viable and fertile and were bred free of Bal1-cre in subsequent generations. Slc7a5 -/- embryos were obtained by inter-crossing heterozygotes and a phenotype was apparent by E9.5. To identify the first cellular processes affected by Slc7a5 loss RNAseq was carried out to compare transcriptomes of null and wildtype E8.5 embryos.
Project description:DNA methylation is highly dynamic during mammalian embryogenesis. It is broadly accepted that the paternal genome is actively depleted of global cytosine methylation at fertilization, followed by passive depletion that reaches a minimum at the blastocyst stage. However, this model is based on limited data, and to date no base-resolution maps exist to support and refine it. Here, we generated genome-scale DNA methylation maps in mouse gametes and through post-implantation embryogenesis. We find that the oocyte already exhibits global hypomethylation, most prominently at specific subfamilies of LINE-1 and LTR-containing retro-elements, which are disparate between gametes and resolve to lower methylation values in zygote. Surprisingly, the oocyte contributes a unique set of Differentially Methylated Regions (DMRs), including many CpG Island promoter regions, that are maintained in the early embryo but are lost at the onset of embryonic specification and absent in somatic cells. In contrast, sperm contributed methylation includes retrotransposons that become completely methylated after the blastocyst stage. Our data provide a complete genome-scale, base-resolution timeline of DNA methylation in the pre-specified embryo, when this epigenetic modification is most dynamic and before returning to the canonical somatic pattern. Comparison of DNA methylation patterns in mouse gametes and through embryogenesis using Reduced Representation Bisulfite Sequencing (RRBS)
Project description:Somites are transient embryonic structures consisting of hundreds of cells that bud off from the anterior tip of the presomitic mesoderm on each side of the neural tube. They give rise to the vertebrae and associated skeletal muscles, nerves, and blood vessels. To characterise the transcriptional changes that orchestrate mouse somitogenesis, we have generated coupled RNA-seq and ATAC-seq profiles of individual somites, across embryonic development. We collected the three most posterior pairs of somites, which correspond to those most recently segmented, from embryos containing 8, 18, 21, 25, 27 and 35 pairs of somites. The three somites are labelled I, II and III from the most posterior to the most anterior. From each pair, one somite was used for RNA-seq and the other one for ATAC-seq.