Biological networks are inherently modular, yet little is known about how modules are assembled to enable coordinated and complex functions. We used RNAi and time-series, whole-genome microarray analyses to systematically perturb and characterize components of a C. elegans lineage-specific transcriptional regulatory network. These data are supported by select reporter gene analyses and comprehensive yeast-one-hybrid and promoter sequence analyses. Based on these results we define and characterize two modules composed of muscle- and epidermal-specifying transcription factors that function together within a single cell lineage to robustly specify multiple cell types. The expression of these two modules, although positively regulated by a common factor, is reliably segregated among daughter cells. Our analyses indicate that these modules repress each other, and we propose that this cross-inhibition coupled with their relative time of induction function to enhance the initial asymmetry in their expression patterns, thus leading to the observed invariant gene expression patterns and cell lineage. The coupling of asynchronous and topologically distinct modules may be a general principle of module assembly that functions to potentiate genetic switches.
Pairing of competitive and topologically distinct regulatory modules enhances patterned gene expression.
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No associated publication
Sex, Age, Specimen part, Subject
View SamplesDNA methylation has an impact on regulation of gene expression, however the relation between the two is complex. By performing an integrative analysis of the methylome and transcriptome of the four main circulating immune cell-subsets from healthy females, namely B cells, monocytes, CD4 and CD8 T cells, the relation between the two was characterized. In addition, in light of the known sex bias in the prevalence of several immune-mediated diseases, the female datasets were compared with similar public available male datasets. Immune subset-specific differentially methylated regions (DMRs) were found to be highly similar between males and females; however numerous sex-specific DMRs shared by the four leukocytes subsets were identified, most located on autosomal chromosomes. This provides a list of highly interesting candidate genes to be studied in diseases with sexual dimorphism like autoimmunity. Immune cell-specific DMRs were mainly located in the gene body and intergenic region, distant from CpG islands but overlapping with enhancer elements, thus indicating the importance of distal regulatory elements in leukocyte subsets. In contrast; sex-specific DMRs were over-represented in CpG islands, suggesting some difference in regulation between sex and immune-cell specificity. Both positive and negative correlations between cell-specific expression and methylation were observed, with negative correlation being more frequent. Our acquired immune cell- and sex- specific methylome and transcriptome profiles provide novel insight on their complex regulatory interactions, and may particularly contribute to research of immune-mediated diseases.
No associated publication
Sex, Age, Specimen part, Subject
View SamplesExploring the expression profile of ovarian clear cell carcinoma cancer cell subpopulations- derived tumors grown within a murine and a human cellular tissues.
Niche-dependent gene expression profile of intratumoral heterogeneous ovarian cancer stem cell populations.
Specimen part
View SamplesL-3,4-dihydroxyphenylalanine (levodopa) treatment is the major pharmacotherapy for Parkinson's disease. However, almost all patients receiving levodopa eventually develop debilitating involuntary movements (dyskinesia). While it is known that striatal spiny projection neurons (SPNs) are involved in the genesis of this movement disorder, the molecular basis of dyskinesia is not understood. In this study, we identify distinct cell-type-specific gene expression changes that occur in sub-classes of SPNs upon induction of a parkinsonian lesion followed by chronic levodopa treatment. We identify several hundred genes whose expression is correlated with levodopa dose, many of which are under the control of AP-1 and ERK signaling. In spite of homeostatic adaptations involving several signaling modulators, AP-1-dependent gene expression remains highly dysregulated in direct pathway SPNs (dSPNs) upon chronic levodopa treatment. We also discuss which molecular pathways are most likely to dampen abnormal dopaminoceptive signaling in spiny projection neurons, hence providing potential targets for antidyskinetic treatments in Parkinson's disease.
Molecular adaptations of striatal spiny projection neurons during levodopa-induced dyskinesia.
Specimen part, Treatment
View SamplesThis study explores the impact of lifestyle and environment on gene expression through whole transcriptome profiling of peripheral blood samples in Fijian population (native Melanesians and Indians) living in the rural and urban areas.
Using blood informative transcripts in geographical genomics: impact of lifestyle on gene expression in fijians.
Sex, Age, Specimen part, Subject
View SamplesThe fungal pathogen Ustilago maydis establishes a biotrophic relationship with its host plant maize. Hallmarks of the disease are large plant tumors in which fungal proliferation occurs. Plants have developed various defense pathways to cope with pathogens. We used microarrays to detail the global programme of gene expression during the infection process of Ustilago maydis in its host plant to get insights into the defense programs and the metabolic reprogramming needed to supply the fungus with nutrients.
Ustilago maydis infection strongly alters organic nitrogen allocation in maize and stimulates productivity of systemic source leaves.
Specimen part
View SamplesEbf1 is a transcription factor with documented, and dose dependent, functions in both normal and malignant B-lymphocyte development. In order to understand more about the role of Ebf1 in malignant transformation, we have investigated the impact of reduced functional Ebf1 dose on early B-cell progenitors. Gene expression analysis in loss and gain of function analysis suggested that Ebf1 was involved in the regulation of genes of importance for DNA repair as well as cell survival. Investigation of the level of DNA damage in steady state as well as after induction of DNA damage by UV light supported that pro-B cells lacking one functional allele of Ebf1 display a reduced ability to repair DNA damage. This was correlated to a reduction in expression of Rad51 and combined analysis of published 4C and chromatin Immuno precipitation data suggested that this gene is a direct target for Ebf1. Even though the lack of one allele of Ebf1 did not result in any dramatic increase of tumor formation, we noted a dramatic increase in the formation of pro-B cell leukemia in mice carrying a combined heterozygote mutation in the Ebf1 and Pax5 genes. Even though the tumors were phenotypically similar and stable, we noted a large degree of molecular heterogeneity well in line with a mechanism involving impaired DNA repair. Our data support the idea that Ebf1 controls homologous DNA repair in a dose dependent manner and that this may explain the frequent involvement of Ebf1 in human leukemia
Ebf1 heterozygosity results in increased DNA damage in pro-B cells and their synergistic transformation by Pax5 haploinsufficiency.
Specimen part, Cell line, Time
View SamplesSamples of primary tumors collected from 23 ovarian cancer patients
Machine learning predicts individual cancer patient responses to therapeutic drugs with high accuracy.
Sex, Specimen part, Disease
View SamplesMicroRNAs (miRNAs) are short (~22 nucleotides) regulatory RNAs that can modulate gene expression and are aberrantly expressed in many diseases including cancer. Previous studies have shown that miRNAs inhibit the translation and facilitate the degradation of their targeted mRNAs making them attractive candidates for use in cancer therapy. However, the potential clinical utility of miRNAs in cancer therapy rests heavily upon our ability to understand and accurately predict the consequences of fluctuations in levels of miRNAs within the context of complex tumor cells. To evaluate the predictive power of current models, levels of miRNAs and their targeted messenger RNAs (mRNAs) were measured in laser captured micro-dissected (LCM) ovarian cancer epithelial cells (CEPI) and compared with levels present in ovarian surface epithelial cells (OSE). We found that the predicted inverse correlation between changes in levels of miRNAs and levels of their mRNA targets held for only ~6-11% of predicted target mRNAs. Our results underscore the complexities of miRNA-mediated regulation in vivo and caution against the widespread clinical application of miRNAs and miRNA inhibitors until the basis of these complexities is more fully understood.
Evidence for the complexity of microRNA-mediated regulation in ovarian cancer: a systems approach.
Cell line
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