Metastasis is the leading cause of death for cancer patients. Consequently it is imperative that we improve our understanding of the molecular mechanisms that underlie progression of tumour growth towards malignancy. Advances in genome characterisation technologies have been very successful in identifying commonly mutated or misregulated genes in a variety of human cancers. However the difficulty in evaluating whether these candidate genes drive tumour progression remains a major challenge. Using the genetic amenability of Drosophila melanogaster we generated tumours with specific genotypes in the living animal and carried out a detailed systematic loss-of-function analysis to identify conserved genes that enhance or suppress epithelial tumour progression. This enabled the discovery of functional cooperative regulators of invasion and the establishment of a network of conserved invasion suppressors. This includes constituents of the cohesin complex, which can either promote individual or collective invasion, depending on the severity of effect on cohesin function.
A Genetic Analysis of Tumor Progression in Drosophila Identifies the Cohesin Complex as a Suppressor of Individual and Collective Cell Invasion.
Cell line
View SamplesThe aim of this study was to assess the impact of oocyte competence on subsequent fertility. Based on knowledge already accessible in mammals and on bioinformatics tools including the chicken genome sequence, we focused on the expression of genes involved in the processes of fertilization and of early embryo development. The study was performed using two complementary approaches: a descriptive study of standard laying hens and then a differential study performed with hens from experimental lines expressing broad variations of achieved fertility (approximately 20 per cent). A differential kinetic study is performed on INRA lines selected on the basis of their fertility potential in purpose of hopefully access gene markers of fertility performance.
Identification of germinal disk region derived genes potentially involved in hen fertility.
No sample metadata fields
View SamplesThe aim of this study was to assess the impact of oocyte competence on subsequent fertility. Based on knowledge already accessible in mammals and on bioinformatics tools including the chicken genome sequence, we focused on the expression of genes involved in the processes of fertilization and of early embryo development.
Search for the genes involved in oocyte maturation and early embryo development in the hen.
No sample metadata fields
View SamplesSR proteins are well-characterized RNA binding proteins that promote exon inclusion by binding to exonic splicing enhancers (ESEs). However, it has been unclear whether regulatory rules deduced on model genes apply generally to activities of SR proteins in the cell. Here, we report global analyses of two prototypical SR proteins SRSF1 (SF2/ASF) and SRSF2 (SC35) using splicing-sensitive arrays and CLIP-seq on mouse embryo fibroblasts (MEFs). Unexpectedly, we find that these SR proteins promote both inclusion and skipping of exons in vivo, but their binding patterns do not explain such opposite responses. Further analyses reveal that loss of one SR protein is accompanied by coordinated loss or compensatory gain in the interaction of other SR proteins at the affected exons. Therefore, specific effects on regulated splicing by one SR protein actually depend on a complex set of relationships with multiple other SR proteins in mammalian genomes. Overall design: SRSF1 and SRSF2 CLIP-seq
Genome-wide analysis reveals SR protein cooperation and competition in regulated splicing.
Specimen part, Subject
View SamplesIn the clinical setting, mutations in the CFTR gene enhance the inflammatory response to P. aeruginosa (PA01) infection, but measurements of the inflammatory response to pathogen stimulation by isolated airway epithelia can yield variable results. In this series, we exposed CFBE41o- cells over-expressing F508/F508 CFTR and CFBE41o- cells rescued with wt-CFTR to P. aeruginosa biofilms. P. aeruginosa elicited a more robust increase in cytokine and chemokine expression (e.g., IL-8, CXCL2, CXCL3, CXCR4 and TNF-) in CFBE-wt-CFTR cells compared to CFBE-F508-CFTR cells. These results demonstrate that CFBE41o- cells complemented with wt-CFTR mount a more robust inflammatory response to P. aeruginosa than CFBE41o- F508/F508-CFTR cells.
Does the F508-CFTR mutation induce a proinflammatory response in human airway epithelial cells?
Specimen part
View SamplesWhile the hypothalamo-pituitary-adrenal axis (HPA) activates a general stress response by increasing glucocorticoid (Gc) synthesis, biological stress resulting from infections triggers the inflammatory response through production of cytokines. The pituitary gland integrates some of these signals by responding to the pro-inflammatory cytokines IL6 and LIF and to a negative Gc feedback loop. The present work used whole-genome approaches to define the LIF/STAT3 regulatory network and to delineate cross-talk between this pathway and Gc action. Genome-wide ChIP-chip identified 3 449 STAT3 binding sites, whereas 2 396 genes regulated by LIF and/or Gc were found by expression profiling. Surprisingly, LIF on its own changed expression of only 85 genes but the joint action of LIF and Gc potentiated the expression of more than a thousand genes. Accordingly, activation of both LIF and Gc pathways also potentiated STAT3 and GR recruitment to many STAT3 targets. Our analyses revealed an unexpected gene cluster that requires both stimuli for delayed activation: 83% of the genes in this cluster are involved in different cell defense mechanisms. Thus, stressors that trigger both general stress and inflammatory responses lead to activation of a stereotypic innate cellular defense response.
Regulatory network analyses reveal genome-wide potentiation of LIF signaling by glucocorticoids and define an innate cell defense response.
Specimen part, Time
View SamplesFetal mice (16 days gestation) were administered feline immunodeficiency virus (FIV)-based lentiviral viral particles containing the gene encoding GFP. Six liver tumors developed in three mice between the ages of 273 and 484 days, each mouse developed 2 tumors. These tumors and non-tumorous liver tissue from the same animals and animals that did not develop tumors and untransduced controls were harvested and microarrays were performed on total RNA extracted from these samples. We were interested in investigating the link between lentiviral integration and gene expression.
Transduction of fetal mice with a feline lentiviral vector induces liver tumors which exhibit an E2F activation signature.
Sex, Age, Specimen part
View Samples[Hela cells]: We performed cdr2 knockdown with a pool of 4 cdr2-specific siRNAs to test whether cdr2 may regulate c-myc target genes as cells passage through mitosis.
The onconeural antigen cdr2 is a novel APC/C target that acts in mitosis to regulate c-myc target genes in mammalian tumor cells.
Cell line
View SamplesThe Mre11 complex (Mre11, Rad50, and Nbs1) and Chk2 have been implicated in the DNA damage response, an inducible process required for the suppression of malignancy. The Mre11 complex is predominantly required for repair and checkpoint activation in S phase, while Chk2 governs apoptosis. We examined the relationship between the Mre11 complex and Chk2 in the DNA damage response via the establishment of Nbs1B/B Chk2-/- and Mre11ATLD1/ATLD1 Chk2-/- mice. Chk2 deficiency did not modify the checkpoint defects or chromosomal instability of Mre11 complex mutants; however, the double mutant mice exhibited synergistic defects in DNA damage-induced p53 regulation and apoptosis. Nbs1B/B Chk2-/- and Mre11ATLD1/ATLD1 Chk2-/- mice were also predisposed to tumors. In contrast, DNA-PKcs deficient mice, in which G1-specific chromosome breaks are present, did not exhibit synergy with Chk2-/- mutants. These data suggest that Chk2 suppresses the oncogenic potential of DNA damage arising during S and G2 phases of the cell cycle.
Chk2 suppresses the oncogenic potential of DNA replication-associated DNA damage.
No sample metadata fields
View SamplesThe objective of the present investigation was to utilize the GeneChip Porcine Genome Array from Affymetrix possessing 20, 201 unique probe sets to identify differentially expressed genes during rapid trophoblastic elongation and attachment to the uterine surface in the pig. Identification and characterization of conceptus gene expression patterns during rapid trophoblastic elongation and attachment in the pig will provide a better understanding of the events required for successful implantation and embryonic survival.
Identification of differential gene expression during porcine conceptus rapid trophoblastic elongation and attachment to uterine luminal epithelium.
No sample metadata fields
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