Chromatin remodeling enzyme Brg1 is required for mouse lens fiber cell terminal differentiation and their denucleation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Jiri Zavadil
PROVIDER: E-GEOD-25169 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Genome-wide approach to identify the cell-autonomous role of Brg1 in lens fiber cell terminal differentiation. To examine roles of Brg1 in mouse lens development, a dnBrg1 transgenic construct was expressed using the lens-specific alphaA-crystallin promoter in postmitotic lens fiber cells. Morphological studies revealed abnormal lens fiber cell differentiation in transgenic lenses resulting in cataract. Electron microscopic studies showed abnormal lens suture formation and incomplete karyolysis (denucleation) of lens fiber cells. To identify genes regulated by Brg1, RNA expression profiling was performed in E15.5 embryonic wild type and dnBrg1 transgenic lenses. In addition, comparisons between differentially expressed genes in dnBrg1 transgenic, Pax6 heterozygous, and Hsf4 homozygous lenses identified multiple genes co-regulated by Brg1, Hsf4 and Pax6. Among them DNase IIbeta, a key enzyme required for lens fiber cell denucleation, was found downregulated in each of the Pax6, Brg1 and Hsf4 model systems. Lens-specific deletion of Brg1 using conditional gene targeting demonstrated that Brg1 was required for lens fiber cell differentiation and indirectly for retinal development but was not essential for lens lineage formation. Wild type and dnBrg1 transgenic lenses, 4 biological replicates each
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Project description:Differential expression of HSF4 in null newborn mouse and wildtype lenses was examined to identify putative downstream targets of HSF4. To examine roles of Brg1 in mouse lens development, a dnBrg1 transgenic construct was expressed using the lens-specific aA-crystallin promoter in postmitotic lens fiber cells. Morphological studies revealed abnormal lens fiber cell differentiation in transgenic lenses resulting in cataract. Electron microscopic studies showed abnormal lens suture formation and incomplete karyolysis (denucleation) of lens fiber cells. To identify genes regulated by Brg1, RNA expression profiling was performed in E15.5 embryonic wild type and dnBrg1 transgenic lenses. In addition, comparisons between differentially expressed genes in dnBrg1 transgenic, Pax6 heterozygous, and Hsf4 homozygous lenses identified multiple genes co-regulated by Brg1, Hsf4 and Pax6. Among them DNase IIb, a key enzyme required for lens fiber cell denucleation, was found downregulated in each of the Pax6, Brg1 and Hsf4 model systems. Lens-specific deletion of Brg1 using conditional gene targeting demonstrated that Brg1 was required for lens fiber cell differentiation and indirectly for retinal development but was not essential for lens lineage formation. Keywords: Differential mRNA Expression Three biological replicate experiments were performed with HSF null and wildtype lenses.
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Project description:Background: FGF signaling controls numerous processes during cell lineage specification, organogenesis and terminal differentiation. In lens, FGF signaling was implicated as the key pathway that controls lens fiber cell differentiation, but little is known about its full range and spectrum of regulated genes. Results: Herein, we employed rat lens epithelial explant system and performed RNA and microRNA expression profiling in cells induced to differentiate by FGF2. The primary data were collected at explants grown overnight in the presence of 5 ng/ml of FGF2, followed by a treatment with 100 ng/ml of FGF2 and collection of samples at 2, 4, 12 and 24 hours. Global analysis identified extensive FGF2-regulated cellular responses that were both independent and dependent on microRNAs (miRNAs). We identified a total number of 131 FGF2-regulated miRNAs. Forty-four of these microRNAs had at least two predicted and inversely regulated target RNA molecules. The genes regulated by the highest number of miRs include Nfib, Nfat5, c-Maf, Ets1 and N-Myc, all encoding DNA-binding transcription factors. Analysis of RNA data revealed that activated FGF signaling influenced other major signaling pathways known to regulate lens differentiation including BMP/TGF-M-NM-2, Notch, and Wnt signaling. In the M-bM-^@M-^\earlyM-bM-^@M-^] response phase (2-4 hours), miRNAs targeted expression of batteries of genes that control transcription, cell death, cell proliferation, cell junction, and protein serine/threonine kinase activity. In M-bM-^@M-^\lateM-bM-^@M-^] stages (12-24 hours), the main miRNA targets included regulators of cell cycle arrest and cellular differentiation. Specific miRNA:mRNA interaction networks were identified for c-Maf, N-Myc, and Nfib (DNA-binding transcription factors); Cnot6, Dicer1, Fbx33 and Wdr47 (RNA processing); Ash1l, Med1/PBP and Kdm5b (chromatin remodeling); and c-Maf, Ets1 and Stc1 (FGF signaling). MicroRNAs including miR-9, -143, -155, -455 and -543 downregulated expression of c-Maf in the 3M-bM-^@M-^Y-UTR luciferase reporter asssays. The functional requirement for miRNAs in lens was further demonstrated via disrupted lens fiber cell differentiation in lenses with inactivated Dicer1. Conclusions: These studies demonstrate for the first time global impact of activated FGF signaling in lens cell culture system and identified novel gene regulatory networks (GRNs) connected by multiple miRNAs. Differential gene expression of FGF2-treated lens cell cultures was analyzed at 0, 2, 4, 12 and 24 hours following the treatment. Two biological replicate experiments were performed.
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Project description:Human uterine leiomyomas (ULM) are characterized by dysregulation of a large number of genes and non-coding regulatory microRNAs. In order to identify microRNA::mRNA associations relevant to ULM pathogenesis, we examined global correlation patterns between the altered microRNA expression and the predicted target genes in leiomyomas and matched myometria. We found that some but not all of the predicted and inversely correlated target genes in ULMs can be directly regulated by microRNAs in vitro. Our findings provide a broad overview of molecular events underlying the tumorigenesis of uterine leiomyoma and identify select genetic and regulatory events that alter microRNA expression and may play important roles in ULM pathobiology by positively regulating tumor growth while maintaining the non-invasive character of ULMs Keywords: Differential gene expression Paired normal (myometrium) and tumor (ULM) samples derived from 5 patients were used
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Project description:Genome-wide approach to identify the cell-autonomous role of Brg1 in lens fiber cell terminal differentiation. To examine roles of Brg1 in mouse lens development, a dnBrg1 transgenic construct was expressed using the lens-specific alphaA-crystallin promoter in postmitotic lens fiber cells. Morphological studies revealed abnormal lens fiber cell differentiation in transgenic lenses resulting in cataract. Electron microscopic studies showed abnormal lens suture formation and incomplete karyolysis (denucleation) of lens fiber cells. To identify genes regulated by Brg1, RNA expression profiling was performed in E15.5 embryonic wild type and dnBrg1 transgenic lenses. In addition, comparisons between differentially expressed genes in dnBrg1 transgenic, Pax6 heterozygous, and Hsf4 homozygous lenses identified multiple genes co-regulated by Brg1, Hsf4 and Pax6. Among them DNase IIbeta, a key enzyme required for lens fiber cell denucleation, was found downregulated in each of the Pax6, Brg1 and Hsf4 model systems. Lens-specific deletion of Brg1 using conditional gene targeting demonstrated that Brg1 was required for lens fiber cell differentiation and indirectly for retinal development but was not essential for lens lineage formation.
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