Terminal differentiation of epidermal cells in Drosophila embryos requires the activity of a transcription factor. Svb is necessary and sufficient to induce this process. pri is a regulator of Svb activity, converting it from a repressor into an activator. To characterize the downstream Svb and pri effectors in cell morphogenesis, we performed microarrays in wt, svb -/- (no gene) and pri -/- (svb repressor) mutant conditions.
Genome-wide analyses of Shavenbaby target genes reveals distinct features of enhancer organization.
Specimen part
View SamplesThe Wilms tumor 1 gene (WT1) encodes a transcription factor involved in cell growth and development. As we previously reported WT1 expression is hardly detectable in normal hepatic tissue but is induced in liver cirrhosis. Although WT1 has been found to be overexpressed in a number of malignancies, the role of WT1 in hepatocarcinogenesis has not been clarified. We found that WT1 is expressed in several human hepatocellular carcinoma (HCC) cell lines including PLC/PRF/5 and HepG2, and in HCC tumor tissue in 42% of patients. WT1 small interfering RNAs did not affect proliferation rate of HCC cells but abrogated their resistance to anoikis. Transcriptome analysis of PLC/PRF/5 cells after WT1 knockdown demonstrated upregulation of 251 genes and downregulation of 321. Ninety per cent of the former corresponded to metabolic genes mostly those characterizing the mature hepatocyte phenotype. On the contrary, genes that decreased upon WT1 inhibition were mainly related to defense against apoptosis, cell cycle and tumor progression. In agreement with these findings WT1 expression increased the resistance of liver tumor cells to doxorubicin, a compound used to treat HCC. Interestingly, doxorubicin strongly enhanced WT1 expression in both HCC cells and normal human hepatocytes. Among different chemotherapeutics, induction of WT1 transcription was restricted to topoisomerase 2 inhibitors. When WT1 expression was prohibited doxorubicin caused a marked increase in caspase-3 activation. In conclusion, WT1 is expressed in a substantial proportion of HCC contributing to tumor progression and resistance to chemotherapy, suggesting that WT1 may be an important target for HCC treatment.
Wilms' tumor 1 gene expression in hepatocellular carcinoma promotes cell dedifferentiation and resistance to chemotherapy.
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View SamplesThe equilibrium between cellular differentiation and proliferation is fundamental for tissue homeostasis. This is particularly important for the liver, a highly differentiated organ with systemic metabolic functions still endowed with unparalleled regenerative potential. Hepatocellular de-differentiation and uncontrolled proliferation are at the basis of liver carcinogenesis. We have identified SLU7, a pre-mRNA splicing regulator inhibited in hepatocarcinoma as a pivotal gene for hepatocellular homeostasis. SLU7 knockdown in human liver cells and mouse liver resulted in profound changes in pre-mRNA splicing and gene expression, leading to impaired glucose and lipid metabolism, refractoriness to key metabolic hormones, and reversion to a fetal-like gene expression pattern. Hepatocellular proliferation and a switch to a tumor-like glycolytic phenotype were also observed. Mechanistically, SLU7 governed the splicing and/or expression of essential genes for hepatocellular differentiation like SRSF3 and HNF4a, and was identified as a critical factor in cAMP-regulated gene transcription. SLU7 is therefore central for hepatocyte identity and quiescence.
Splicing regulator SLU7 is essential for maintaining liver homeostasis.
Cell line
View SamplesIn vitro oocyte maturation (IVM) holds great promise as a tool for enhancing clinical treatment of infertility, enhancing availability of non human primates for development of disease models, and facilitating endangered species preservation. However, IVM outcomes have remained significantly below success rates obtained using in vivo matured (VVM) oocytes from humans and non human primates. A cDNA array based analysis is presented, comparing the transcriptomes of VVM oocytes with IVM oocytes. We observe a small set of just 59 mRNAs that are differentially expressed between the two cell types. These mRNAs are related to cellular homeostasis, cell-cell interactions including growth factor and hormone stimulation and cell adhesion, and other functions such as mRNA stability and translation. Additionally, we observe in IVM oocytes overexpression of PLAGL1 and MEST, two maternally imprinted genes, indicating a possible interruption or loss of correct epigenetic programming. These results indicate that, under certain IVM conditions, oocytes that are molecularly highly similar to VVM oocytes can be obtained, however the interruption of normal oocyte-somatic cell interactions during the final hours of oocyte maturation may preclude the establishment of full developmental competence.
Effects of in vitro maturation on gene expression in rhesus monkey oocytes.
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View SamplesThe oocytes of many species, both invertebrate and vertebrate, contain a large collection of localized determinants in the form of proteins and translationally inactive maternal mRNAs. However, it is unknown whether mouse oocytes contain localized MmRNA determinants and what mechanisms might be responsible for their control. We collected intact MII oocytes, enucleated MII oocyte cytoplasts (with the spindle removed), and spindle-chromosome complexes which had been microsurgically removed. RNA was extracted, amplified, labeled, and applied to microarrays to determine if any MmRNA determinants were localized to the SCC.
Association of maternal mRNA and phosphorylated EIF4EBP1 variants with the spindle in mouse oocytes: localized translational control supporting female meiosis in mammals.
Sex, Specimen part, Disease
View SamplesTranscriptional 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 SamplesCumulus oophorus cells play an essential role in oocyte development. CBX4 is a member of the Polycomb complex, which plays a role in regulating cellular differentiation.
Contribution of CBX4 to cumulus oophorus cell phenotype in mice and attendant effects in cumulus cell cloned embryos.
Sex, Specimen part
View SamplesWhile the reprogramming factors OCT4, SOX2, KLF4, and MYC (OSKM) can reactivate the pluripotency network in terminally differentiated cells, they also regulate expression of non-pluripotency genes in other contexts, such as the mouse primitive endoderm. The primitive endoderm is an extraembryonic lineage established alongside the pluripotent epiblast in the blastocyst, and is the progenitor pool for extraembryonic endoderm stem (XEN) cells. Several studies have shown that endodermal genes are upregulated in fibroblasts undergoing reprogramming, although whether endodermal genes promote or inhibit acquisition of pluripotency is unclear. We show that, in fibroblasts undergoing conventional reprogramming, OSKM-induced expression of endodermal genes leads to formation of induced XEN (iXEN) cells, which possess key properties of blastocyst-derived XEN cells, including morphology, transcription profile, self-renewal, and multipotency. Our data show that iXEN cells arise in parallel to iPS cells, indicating that OSKM are sufficient to drive cells to two distinct fates during reprogramming. Overall design: Sequence-based mRNA transcriptional profiling of three different cell lines (MEF, XEN, iXEN) with multiple biological replicates, under two different growth medium conditions (ESC medium, XEN medium) for XEN and iXEN cells.
OSKM Induce Extraembryonic Endoderm Stem Cells in Parallel to Induced Pluripotent Stem Cells.
Specimen part, Treatment, Subject
View SamplesGlobal gene experssion study of the HAEC transcriptional response to artificial chlyomicron remnant-like particles (A-CRLPs) prepared with triglycerides extracted from four natural dietary oils: fish, DHASCO, corn and palm oils. We hypothesised that A-CRLPs could differentially regulate HAEC gene expression according to thier triglyceride content. These data provide an important starting point for investigations into the effects of A-CRLPs on endothelial cells, particulary genes involved in redox balance and inflammatory processes.
Endothelial HO-1 induction by model TG-rich lipoproteins is regulated through a NOX4-Nrf2 pathway.
Specimen part
View SamplesPurpose: Klf5 plays a critical role in the mouse ocular surface (Kenchegowda et al., 2011. Dev Biol. 356:5-18). Here, we compare wild-type (WT) and Klf5-conditional null (Klf5CN) corneal gene expression at postnatal day-11 (PN11) and PN56 to identify the Klf5-target genes. Methods: Gene expression was compared using Affymetrix microarrays with QPCR validation. Transient transfection assays examined the effect of Klf5 on selected target gene promoter activities. Whole-mount corneal immunofluorescent staining examined neovascularization and CD45+ macrophage influx. Results: Expression of 714 and 753 genes was increased, and 299 and 210 genes decreased in PN11 and PN56 Klf5CN corneas, respectively, with 366 concordant increases, 72 concordant decreases and 3 discordant changes. Canonical pathway analysis identified 35 and 34 significantly (p<0.001) enriched pathways at PN11 and PN56, respectively, with 24 common pathways. PN56 Klf5CN corneas shared 327 increases and 91 decreases with the previously described Klf4CN corneas (Swamynathan et al., 2008. IOVS 49:3360-70). Angiogenesis and immune response-related genes were affected consistent with lymphangiogenesis and macrophage influx in Klf5CN corneas, respectively. Expression of 1574 genes was increased and 1915 decreased, in the WT PN56 compared with PN11 corneas. Expression of many collagens, matrix metalloproteinases and other extracellular matrix associated genes decreased in WT corneas between PN11 and PN56, while that of solute carrier family members increased. Conclusions: Differences in PN11 and PN56 corneal Klf5-target genes reveal dynamic changes in Klf5 functions during corneal maturation. Klf4- and Klf5-target genes do not overlap, consistent with their non-redundant roles in the mouse cornea.
Critical role of Klf5 in regulating gene expression during post-eyelid opening maturation of mouse corneas.
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