Transcriptional activation in mammalian embryos occurs in a stepwise manner. In mice, it begins at the late one-cell stage, followed by a minor wave of activation at the early two-cell stage, and then the major genome activation (MGA) at the late two-cell stage. Cellular homeostasis, metabolism, cell cycle, and developmental events are orchestrated before MGA by time-dependent changes in the array of maternal transcripts being translated (i.e., the translatome). Despite the importance of maternal mRNA and its correct recruitment for development, neither the array of recruited mRNA nor the regulatory mechanisms operating have been well cheracterized. We present the first comprehensive analysis of changes in the maternal component of the zygotic translatome during the transition from oocyte to late one-cell stage embryo, revealing global transitions in the functional classes of translated maternal mRNAs, and apparent changes in the underlying cis-regulatory mechanisms.
Analysis of polysomal mRNA populations of mouse oocytes and zygotes: dynamic changes in maternal mRNA utilization and function.
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View SamplesHuntingtons disease (HD) is an incurable hereditary neurodegenerative disorder, which manifests itself as a loss of GABAergic medium spiny (GABA MS) neurons in the striatum and caused by an expansion of the CAG repeat in exon 1 of the huntingtin gene. There is no cure for HD, existing pharmaceutical can only relieve its symptoms. Here, induced pluripotent stem cells were established from patients with low CAG repeat expansion in the huntingtin gene, and were then efficiently differentiated into GABA MS-like neurons under defined culture conditions. Analysis of differentially expressed genes between Huntingtons disease and wild type iPSCs derived GABA MS-like neurons has been performed.
Manifestation of Huntington's disease pathology in human induced pluripotent stem cell-derived neurons.
Age, Specimen part
View SamplesThe aim of this study was to establish an in vitro model to investigate the initial stages of human implantation based on co-culture of a) immortalized cells representing the receptive (Ishikawa) or non-receptive (HEC-1-A) endometrial epithelium with b) spheroids of a trophoblastic cell line (JEG-3) modified to express green fluorescent protein. After co-culturing Ishikawa cells with trophoblast spheroids, 310 and 298 genes increased or decreased their expression compared to non-co-cultured Ishikawa control cells, respectively; only 9 genes (5 increased and 4 decreased) were differentially expressed in HEC-1-A upon co-culture with trophoblast spheroids. Compared to HEC-1-A, the trophoblast challenge to Ishikawa cells differentially regulated the expression of 495 genes. In summary, upon co-culture with the trophoblast spheroids, non-receptive epithelium is characterized by a muted transcriptional response which in turn fails to activate the full transcriptional response that trophoblast spheroids undergo when co-cultured with receptive epithelium. Overall design: GFP expressing JEG-3 spheroids were co-cultured with confluent monolayers of receptive Ishikawa or non-receptive HEC-1-A epithelia. After 48 hours of co-culture, GFP+ (trophoblast JEG-3 spheroid cells) and GFP- cell fractions (receptive Ishikawa or non-receptive HEC-1-A epithelial cells) were isolated by fluorescence-activated flow cytometry (FACS). The specific transcriptional changes of the isolated cell populations were analyzed by RNA-seq profiling. Statistical significance of gene expression differences was set at an absolute log2 fold change (log2FC) =1 and an adjusted p-value <0.05.
Transcriptomic analysis of the interaction of choriocarcinoma spheroids with receptive vs. non-receptive endometrial epithelium cell lines: an in vitro model for human implantation.
Specimen part, Subject
View SamplesUsing bone marrow cells of GFP:Gfi1 knock in mice, we separated Gfi1-high and Gfi1-low expressing cells in the classical CD11b+, GR1-low monocytic cell fraction. We sorted CD11b+, GR1-low GFP:Gfi1-high and low cells as well as CD11b+, GR1-high granulocytes and CD11b-high, GR1-intermediate cells from Gfi1-knock-out mice for further analysis.
Growth factor independence 1 (Gfi1) regulates cell-fate decision of a bipotential granulocytic-monocytic precursor defined by expression of Gfi1 and CD48.
Age, Specimen part
View SamplesLineage negative, CD44 negative, CD25 positive thymocytes were isolated from wt mice or Miz1 POZ-domain knockout mice to analyze the effect of loss of Miz1 in the DN3 population of T-cells
Miz-1 is required to coordinate the expression of TCRbeta and p53 effector genes at the pre-TCR "beta-selection" checkpoint.
Specimen part
View SamplesCloned embryos produced by somatic cell nuclear transfer (SCNT) display a plethora of phenotypic characteristics that make them different from fertilized embryos, indicating defects in the process of nuclear reprogramming by the recipient ooplasm. To elucidate the extent and timing of nuclear reprogramming, we used microarrays to analyze the transcriptome of mouse SCNT embryos during the first two cell cycles. We identified a large number of genes mis-expressed in SCNT embryos. We found that genes involved in transcription and regulation of transcription are prominent among affected genes, and thus may be particularly difficult to reprogram, and these likely cause a ripple effect that alters the transcriptome of many other functions, including oxidative phosphorylation, transport across membrane, and mRNA transport and processing. Interestingly, we also uncovered widespread alterations in the maternal (i.e. non transcribed) mRNA population of SCNT embryos. We conclude that gene expression in early SCNT embryos is grossly abnormal, and that this is at least in part the result of incomplete reprogramming of transcription factor genes.
Tough beginnings: alterations in the transcriptome of cloned embryos during the first two cell cycles.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Growth factor independence 1b (gfi1b) is important for the maturation of erythroid cells and the regulation of embryonic globin expression.
Specimen part
View SamplesGrowth factor independence 1b (Gfi1b) is a DNA binding repressor of transcription with vital functions in hematopoiesis. Gfi1b-null embryos die at midgestation very likely due to defects in erythro- and megakaryopoiesis. To analyze the full functionality of Gfi1b in embryonic erythropoiesis, we used conditionally deficient mice that harbor floxed Gfi1b alleles and one EpoR-Cre knock-in allele.
Growth factor independence 1b (gfi1b) is important for the maturation of erythroid cells and the regulation of embryonic globin expression.
Specimen part
View SamplesGrowth factor independence 1b (Gfi1b) is a DNA binding repressor of transcription with vital functions in hematopoiesis. Gfi1b-null embryos die at midgestation very likely due to defects in erythro- and megakaryopoiesis. To analyze the full functionality of Gfi1b in erythropoiesis, we used conditionally deficient mice that harbor floxed Gfi1b alleles and the Mx-Cre transgene inducible by pIpC treatment.
Growth factor independence 1b (gfi1b) is important for the maturation of erythroid cells and the regulation of embryonic globin expression.
Specimen part
View SamplesThe inner ear develops from a patch of thickened cranial ectoderm adjacent to the hindbrain called the otic placode. Studies in a number of vertebrate species suggest that the initial steps in induction of the otic placode are regulated by members of the Fibroblast Growth Factor (FGF) family, and that inhibition of FGF signaling can prevent otic placode formation. To better understand the genetic pathways activated by FGF signaling during otic placode induction, we performed microarray experiments to estimate the proportion of chicken otic placode genes that can be up-regulated by the FGF pathway in a simple culture model of otic placode induction. Surprisingly, we find that FGF is only sufficient to induce about 15% of chick otic placode-specific genes in our experimental system. However, pharmacological blockade of the FGF pathway in cultured chick embryos showed that although FGF signaling was not sufficient to induce the majority of otic placode-specific genes, it was still necessary for their expression in vivo. These inhibitor experiments further suggest that the early steps in otic placode induction regulated by FGF signaling occur through the MAP kinase pathway. Although our work suggests that FGF signaling is necessary for otic placode induction, it demonstrates that other unidentified signaling pathways are required to co-operate with FGF signaling to induce the full otic placode program.
Analysis of FGF-dependent and FGF-independent pathways in otic placode induction.
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