In order to assess the physiological role of Cop1 in vivo we generated mice that do no longer express the protein. Cop1KO mice die at around E10.5 of embryonic development. In order to gain insights into the molecular mechanisms that cause the embryonic death we compared the genome-wide gene expression profile of E9.5 wild-tytpe and Cop1-null embryos. The data do not support a role for Cop1 in the regulation of the p53 pathway in vivo and highlight a role for Cop1 in cardiovascular development and/or angiogenesis. The abstract of the associated publication is as follows:Biochemical data have suggested conflicting roles for the E3 ubiquitin ligase Cop1 in tumourigenesis. Here we present the first in vivo investigation of the role of Cop1 in cancer aetiology. We used an innovative genetic approach to generate an allelic series of Cop1 and show that Cop1 hypomorphic mice spontaneously develop malignancy at a high frequency in their first year of life and are highly susceptible to radiation-induced lymphomagenesis. Biochemically, we show that Cop1 regulates c-Jun oncoprotein stability and modulates c-Jun/AP1 transcriptional activity in vivo. Cop1-deficiency stimulates cell proliferation in a c-Jun-dependent manner. We conclude that Cop1 is a tumour suppressor that antagonizes c-Jun oncogenic activity in vivo.
Cop1 constitutively regulates c-Jun protein stability and functions as a tumor suppressor in mice.
Specimen part
View SamplesTGF-beta/Smads signaling plays important roles in vascular integrity. To identify potential Smad4 target genes in brain endothelial cells that control cerebrovascular integrity, the microarray assay was performed to compare the gene expression profiles of bEnd3 transfected with Smad4-siRNA and control-siRNA.
Endothelial Smad4 maintains cerebrovascular integrity by activating N-cadherin through cooperation with Notch.
Specimen part, Cell line
View SamplesThe -amyloid precursor protein APP and the related APLPs, undergo complex proteolytic processing giving rise to several fragments. Whereas it is well established that A accumulation is a central trigger for Alzheimer disease (AD), the physiological role of APP family members and their diverse proteolytic products is still largely unknown. The secreted APPs ectodomain has been shown to be involved in neuroprotection and synaptic plasticity. The -secretase generated APP intracellular domain AICD, functions as a transciptional regulator in heterologous reporter assays, although its role for endogenous gene regulation has remained controversial. To gain further insight into the molecular changes associated with knockout phenotypes and to elucidate the physiological functions of APP family members including their proposed role as transcriptional regulators we performed a DNA microarray transcriptome profiling of the frontal cortex of adult wild type, APP-/-, APLP2-/- and APPs knockin (KI) mice, APP/, expressing solely the secreted APPs ectodomain. Biological pathways affected by the lack of APP family members included regulation of neurogenesis, regulation of transcription and regulation of neuron projection development. Comparative analysis of transcriptome changes and qPCR validation identified co-regulated gene sets. Interestingly, these included heat shock proteins and plasticity related genes that were down-regulated in knock-out cortices. In contrast, we failed to detect significant differences in expression of previously proposed AICD target genes including Bace1, Kai1, Gsk3b, p53, Tip60 and Vglut2. Only Egfr was slightly up-regulated in APLP2-/- mice. Comparison of APP-/- and APP/ with wild-type mice revealed a high proportion of co-regulated genes indicating an important role of the C-terminus for cellular signaling. Finally, comparison of APLP2-/- on different genetic backgrounds revealed that background related transcriptome changes may dominate over changes due to the knockout of a single gene. Shared transcriptome profiles corroborated closely related physiological functions of APP family members in the adult central nervous system. As expression of proposed AICD target genes was not altered in adult cortex, this may indicate that these genes are not affected by lack of APP under resting conditions or only in a small subset of cells.
Comparative transcriptome profiling of amyloid precursor protein family members in the adult cortex.
Sex, Specimen part
View SamplesDespite its key role in Alzheimer pathogenesis, the physiological function(s) of the amyloid precursor protein (APP) and of its proteolytic fragments are still poorly understood. The secreted APPs ectodomain has been shown to be involved in neuroprotection and synaptic plasticity. The -secretase generated APP intracellular domain, AICD, functions as a transcriptional regulator in heterologous reporter assays although its role for endogenous gene regulation has remained controversial. Previously, we have generated APPs knockin (KI) mice expressing solely the secreted ectodomain APPs. Here, we generated double mutants (APPs-DM) by crossing APPs-KI mice onto an APLP2-deficient background and show that APPs rescues the postnatal lethality of the majority of APP/APLP2 double knockout mice. Despite normal CNS morphology and unaltered basal synaptic transmission, young APPs-DM mice already showed pronounced hippocampal dysfunction, impaired spatial learning and a deficit in LTP. To gain further mechanistic insight into which domains/proteolytic fragments are crucial for hippocampal APP/APLP2 mediated functions, we performed a DNA microarray transcriptome profiling of prefrontal cortex and hippocampus of adult APLP2-KO (APLP2-/-) and APPs-DM mice (APP/APLP2-/- mice).Interestingly, this analysis failed to reveal major genotype-related transcriptional differences. Expression differences between cortex and hippocampus were, however, readily detectable.
APP and APLP2 are essential at PNS and CNS synapses for transmission, spatial learning and LTP.
Sex, Specimen part
View SamplesAffymetrix Mouse Genome 430 2.0 arrays were used to measure genome-wide gene expression levels. The results show that high-risk human papillomavirus oncogenes E6 and E7 reprogram the cervical cancer microenvironment independently of and synergistically with estrogen, a critical co-factor in cervical cancer development and maintenance.
Human papillomavirus oncogenes reprogram the cervical cancer microenvironment independently of and synergistically with estrogen.
Specimen part, Treatment
View SamplesThe innate immune system is a two-edged sword; it is absolutely required for host defense against infection, but if left uncontrolled can trigger a plethora of inflammatory diseases. Here we used systems biology approaches to predict and validate a gene regulatory network involving a dynamic interplay between the transcription factors NF-B, C/EBP, and ATF3 that controls inflammatory responses. We mathematically modeled transcriptional regulation of Il6 and Cebpd genes and experimentally validated the prediction that the combination of an initiator (NF-B), an amplifier (C/EBP) and an attenuator (ATF3) forms a regulatory circuit that discriminates between transient and persistent Toll-like receptor 4-induced signals. Our results suggest a mechanism that enables the innate immune system to detect the duration of infection and to respond appropriately.
Function of C/EBPdelta in a regulatory circuit that discriminates between transient and persistent TLR4-induced signals.
Sex, Specimen part
View SamplesMouse and human stem cells with features similar to those of embryonic stem cells have been derived from testicular cells. Although pluripotent stem cells have been obtained from defined germline stem cells (GSCs) of mouse neonatal testis, only multipotent stem cells have been obtained so far from defined cells of mouse adult testis. In this study we describe a robust and reproducible protocol for obtaining germline-derived pluripotent stem (gPS) cells from adult unipotent GSCs. Pluripotency of gPS cells was confirmed by in vitro and in vivo differentiation, including germ cell contribution and transmission. As determined by clonal analyses, gPS cells indeed originate from unipotent GSCs. We propose that the conversion process requires a GSC culture microenvironment that depends on the initial number of plated GSCs and the length of culture time.
Induction of pluripotency in adult unipotent germline stem cells.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Evolutionary etiology of high-grade astrocytomas.
Sex, Time
View SamplesReprogramming of somatic cells is a valuable tool to understand the mechanisms of regaining pluripotency and further opens up the possibility of generating patient-specific pluripotent stem cells. Reprogramming of mouse and human somatic cells into pluripotent stem cells, designated as induced pluripotent stem (iPS) cells, has been possible with the expression of the transcription factor quartet Oct4 (also known as Pou5f1), Sox2, c-Myc, and Klf4. Considering that ectopic expression of c-Myc causes tumourigenicity in offspring and retroviruses themselves can cause insertional mutagenesis, the generation of iPS cells with a minimal number of factors may hasten the clinical application of this approach. Here, we show that adult mouse neural stem cells express higher endogenous levels of Sox2 and c-Myc than embryonic stem cells, and that exogenous Oct4 together with either Klf4 or c-Myc are sufficient to generate iPS cells from neural stem cells. These two-factor (2F) iPS cells are similar to embryonic stem cells at the molecular level, contribute to development of the germ line, and form chimeras. We propose that, in inducing pluripotency, the number of reprogramming factors can be reduced when using somatic cells that endogenously express appropriate levels of complementing factors.
Pluripotent stem cells induced from adult neural stem cells by reprogramming with two factors.
No sample metadata fields
View SamplesThe four transcription factors Oct4, Sox2, Klf4, and c-Myc can induce pluripotency in mouse and human fibroblasts. We previously described direct reprogramming of adult mouse neural stem cells (NSCs) by Oct4 and either Klf4 or c-Myc. NSCs endogenously express Sox2, c-Myc, and Klf4 as well as several intermediate reprogramming markers. Here we report that exogenous expression of the germline-specific transcription factor Oct4 is sufficient to generate pluripotent stem cells from adult mouse NSCs. These one-factor induced pluripotent stem (1F iPS) cells are similar to embryonic stem cells in vitro and in vivo. Not only can these cells be efficiently differentiated into NSCs, cardiomyocytes and germ cells in vitro, but they are also capable of teratoma formation and germline transmission in vivo. Our results demonstrate that Oct4 is required and sufficient to directly reprogram NSCs to pluripotency.
Oct4-induced pluripotency in adult neural stem cells.
No sample metadata fields
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