The assembly of the developmentally arrested primordial follicle and subsequent transition to the primary follicle are poorly understood processes critical to ovarian biology. Abnormal primordial follicle development can lead to pathologies such as premature ovarian failure. The current study used a genome-wide expression profile to investigate primordial follicle assembly and development. Rat ovaries with predominantly unassembled, primordial, or primary follicles were obtained. RNA from these ovaries was hybridized to rat microarray gene chips, and the gene expression (i.e., ovarian transcriptome) was compared between the developmental stages. Analysis of the ovarian transcriptome demonstrated 148 genes up-regulated and 50 genes down-regulated between the unassembled and primordial follicle stages. Observations demonstrate 80 genes up-regulated and 44 genes down-regulated between the primordial and primary follicle stages. The analysis demonstrated 2332 genes common among the three developmental stages, 146 genes specific for the unassembled follicles, 94 genes specific for the primordial follicles, and 151 genes specific for the primary follicles. Steroidogenic genes are up-regulated between unassembled and primordial follicles, and then many are again down-regulated between primordial and primary follicles. The hormones inhibin and Mullerian inhibitory substance (MIS) display a similar pattern of expression with the highest levels of mRNA in the primordial follicles. Several novel unknown genes that had dramatic changes in expression during primordial follicle development were also identified. Gene families/clusters identified that were up-regulated from unassembled to primordial follicles include growth factors and signal transduction gene clusters, whereas a down-regulated gene family was the synaptonemal complex genes associated with meiosis. Gene families/clusters that were up-regulated between primordial and primary follicles included immune response genes, metabolic enzymes, and proteases, whereas down-regulated gene families include the globulin genes and some steroidogenic genes. The expression of several growth factors changed during primordial follicle development, including vascular endothelial growth factor and insulin-like growth factor II. Elucidation of how these changes in gene expression coordinate primordial follicle assembly and the primordial to primary follicle transition provides a better understanding of these critical biological processes and allows selection of candidate regulatory factors for further investigation.
Alterations in the ovarian transcriptome during primordial follicle assembly and development.
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View SamplesAnalysis of gene-expression profiles by microarrays can be very useful to characterize new potential candidate genes, key regulatory networks, and to define phenotypes or molecular signatures to improve the diagnosis or classification of the disease. We have used this approach in the study of one of the major causes of allergic diseases in Mediterranean countries, the olive pollen response, in order to find differential molecular markers among five clinical groups, Non-allergic, Asymptomatic, Allergic but not to olive pollen, Non-treated, olive pollen allergic patients and Olive pollen allergic patients (under specific-immunotherapy). The results of gene-expression by principal components analysis (PCA) clearly showed five clusters of samples that correlated with the five clinical groups. Analysis of differential gene-expression by multiple testing, and functional analysis by KEGG and Gene-Ontology revealed differential genes and pathways among the 5 clinical groups.
Differential gene-expression analysis defines a molecular pattern related to olive pollen allergy.
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View SamplesAnalysis of gene-expression profiles with microarrays can be very useful to dissect specific responses and to characterize with a global view, new elements for improving the diagnosis, treatment and understanding of allergic diseases. We have used this approach for studying the olive pollen response, taking advantage our previous results of T-cell epitope mapping on Ole e 1 molecule (the major allergen from olive pollen) in order to analyze the stimuli influence on the gene-expression of olive pollen allergic patients. Peripheral blood mononuclear cells (PBMCs) from 6 healthy controls and 6 allergic subjects were stimulated 24 hours with olive pollen stimuli: Ole e 1 molecule and two Ole e 1 peptides previously defined as P2+3 (aa10-31), mainly recognized by non-allergic subjects (possible immunoregulatory epitope) and P10+12+13 (aa90-130), immunodominant T-cell epitope. RNA extracted from basal and stimulated PBMCs was analyzed by HuGeU133 plus 2.0 GeneChip, Affymetrix (38.500genes). After assessment of data quality by standard quality checks and principal components analysis (PCA), differential gene-expression by experimental conditions was performed by multiple testing, using microarrays specific software. Differences in functional analysis were performed by KEGG, for pathways and Gene-Ontology for biological process. The results of gene-expression by PCA showed differential clusters that correlated with the experimental conditions from samples of allergic patients. Analysis of differential gene-expression by multiple testing, and functional analysis by KEGG and Gene-Ontology revealed differential genes and pathways among the 4 experimental conditions.
Therapeutic targets for olive pollen allergy defined by gene markers modulated by Ole e 1-derived peptides.
Specimen part, Disease
View SamplesExpression of the SS18/SYT-SSX fusion protein is believed to underlie the pathogenesis of synovial sarcoma (SS). Recent evidence suggests that deregulation of the Wnt pathway may play an important role in SS but the mechanisms whereby SS18-SSX might affect Wnt signaling remain to be elucidated. Here, we show that SS18/SSX tightly regulates the elevated expression of the key Wnt target AXIN2 in primary SS. SS18-SSX is shown to interact with TCF/LEF, TLE and HDAC but not -catenin in vivo and to induce Wnt target gene expression by forming a complex containing promoter-bound TCF/LEF and HDAC but lacking -catenin. Our observations provide a tumor-specific mechanistic basis for Wnt target gene induction in SS that can occur in the absence of Wnt ligand stimulation.
The fusion protein SS18-SSX1 employs core Wnt pathway transcription factors to induce a partial Wnt signature in synovial sarcoma.
Cell line
View SamplesTo investigate the impact of ablating Bcl9/Bcl9l on tumorigenesis, 6-8- week-old mice were exposed first to a single dose dimethylhydrazine (DMH, 44 mg/kg body weight), which is metabolized in the liver to carcinogenic azoxymethane (AOM), followed by 7 days oral administration of 2 % dextrane sulfate sodium (DSS) in the drinking water. This regimen results in the emergence of dysplastic adenomas, which progress to differentiated adenocarcinomas that are morphologically similar to human colorectal adenocarcinomas and typically harbor -catenin stabilizing mutations of GSK3 phosphorylation sites. Accordingly, these tumors present hallmarks of active Wnt signaling such as accumulation of nuclear -catenin and expression of Wnt target genes.
Bcl9/Bcl9l are critical for Wnt-mediated regulation of stem cell traits in colon epithelium and adenocarcinomas.
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View SamplesThe mammalian genome contains thousands of loci that transcribe long noncoding RNAs (lncRNAs), some of which are known to play critical roles in diverse cellular processes through a variety of mechanisms. While some lncRNA loci encode RNAs that act non-locally (in trans), emerging evidence indicates that many lncRNA loci act locally (in cis) to regulate expression of nearby genes—for example, through functions of the lncRNA promoter, transcription, or transcript itself. Despite their potentially important roles, it remains challenging to identify functional lncRNA loci and distinguish among these and other mechanisms. To address these challenges, we developed a genome-scale CRISPR-Cas9 activation screen targeting more than 10,000 lncRNA transcriptional start sites (TSSs) to identify noncoding loci that influence a phenotype of interest. We found 11 novel lncRNA loci that, upon recruitment of an activator, each mediate BRAF inhibitor resistance in melanoma. Most candidate loci appear to regulate nearby genes. Detailed analysis of one candidate, termed EMICERI, revealed that its transcriptional activation results in dosage-dependent activation of four neighboring protein-coding genes, one of which confers the resistance phenotype. Our screening and characterization approach provides a CRISPR toolkit to systematically discover functions of noncoding loci and elucidate their diverse roles in gene regulation and cellular function. Overall design: RNA-seq on A375 cells overexpressing candidate lncRNA or protein-coding gene.
Genome-scale activation screen identifies a lncRNA locus regulating a gene neighbourhood.
Specimen part, Cell line, Subject
View SamplesThe objective of this study was to make use of gene expression signatures and functional assays to delineate differences between various intestinal colon carcinoma cell lines and normal intestinal epithelium to assess their appropriateness as a tumor model or for drug absorption studies.
Defining new criteria for selection of cell-based intestinal models using publicly available databases.
Specimen part, Cell line
View SamplesCanonical Wnt signaling output is mediated by ß-catenin, which interacts with LEF/TCF transcription factors and recruits a general transcriptional activation complex to its C-terminus. Its N-terminus binds BCL9/9L proteins, which bind co-activators that in mammals contribute to fine-tuning the transcriptional output. We found that a BCL9/9L-dependent gene expression signature was strongly associated with patient outcome in colorectal cancer and that stem cell and mesenchymal genes determine its prognostic value. Abrogating BCL9/9L-ß-catenin signaling in independent mouse colorectal cancer models resulted in virtual loss of these traits, and oncogenic intestinal organoids lacking BCL9/9L proteins proved no longer tumorigenic. Our findings suggest that the BCL9/9L arm of Wnt-ß-catenin signaling sustains a stemness-to-differentiation equilibrium in colorectal cancer, which critically affects disease outcome. Mutational activation of the Wnt pathway is a key oncogenic event in colorectal cancer. Targeting the pathway downstream of activating mutations is challenging, and the therapeutic window is limited by intestinal toxicity. Contrasting with phenotypes caused by inactivating key Wnt pathway components, ablation of BCL9/9L proteins in adult mice indicated that they were dispensable for intestinal homeostasis, consistent with their role in tuning transcription. Cancer stem cells are increasingly recognized as responsible for tumor recurrence. The correlation between stemness traits in colorectal cancer models and BCL9/9L-ß-catenin signaling suggests that high Wnt signaling output is required for their maintenance. Our findings suggest that pruning Wnt-ß-catenin signaling might be well tolerated and prove sufficient for trimming stemness traits and improving disease outcome. Overall design: Examination of Bcl9/9l-knockout versus wild-type transcriptome in murine AOM-DSS tumors, APC-Kras tumors and healthy colocyte extracts.
BCL9/9L-β-catenin Signaling is Associated With Poor Outcome in Colorectal Cancer.
No sample metadata fields
View SamplesRNA-seq and ATAC-seq data to understand how gene regulation and chromatin accessibility correlates with function enrichment in CRISPR screen for melanoma drug resistance
Genome-scale activation screen identifies a lncRNA locus regulating a gene neighbourhood.
No sample metadata fields
View SamplesIn the yeast Saccharomyces cerevisiae, cleavage factor I (CFI) and cleavage and polyadenylation factor (CPF) build the core of the transcription termination machinery. CFI comprises the Rna14, Rna15, Pcf11, and Clp1 proteins, as well as the associated Hrp5 RNA-binding protein. We found that CFI participates in the DNA damage response and that rna14-1 shows synthetic growth defects with mutants of different repair pathways, including homologous recombination, non-homologous end joining, post replicative repair, mismatch repair, and nucleotide excision repair, implicating that impaired RNAPII termination and 3-end processing decreases the cellular tolerance for DNA damage. Beyond replication progression defects, we found that bypass of the G1/S checkpoint in rna14-1 cells leads to synthetic sickness, accumulation of phosphorylated H2A, as well as increase in Rad52-foci and in recombination. Our data provide evidence that CFI dysfunction impairs RNAPII turnover, leading to replication hindrance and lower tolerance to exogenous DNA damage. These findings underscore the importance of coordination between transcription termination, DNA repair and replication in the maintenance of genomic stability.
Cleavage factor I links transcription termination to DNA damage response and genome integrity maintenance in Saccharomyces cerevisiae.
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