Several aspects common to a Western lifestyle, including obesity and decreased physical activity, are known risks for gastrointestinal cancers. There is an increasing amount of evidence suggesting that diet profoundly affects the composition of the intestinal microbiota. Moreover, there is now unequivocal evidence linking a dysbiotic gut to cancer development. Yet, the mechanisms through which high-fat diet (HFD)-mediated changes in the microbial community impact the severity of tumorigenesis in the gut, remain to be determined.
High-fat-diet-mediated dysbiosis promotes intestinal carcinogenesis independently of obesity.
Sex, Age, Specimen part, Treatment
View SamplesThese experiments are designed to discover genes that are expressed selectively by synaptic nuclei in skeletal muscle with the particular goal of identifying genes that regulate motor axon growth and differentiation.
CD24 is expressed by myofiber synaptic nuclei and regulates synaptic transmission.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Integrative genomics identifies molecular alterations that challenge the linear model of melanoma progression.
Cell line
View SamplesThe two most common melanoma histopathologic subtypes, superficial spreading (SSM) and nodular melanoma (NM), are believed to represent sequential phases of linear progression from radial to vertical growth. Studies suggest, however, that SSM and NM are biologically distinct. We utilized an integrative genomic approach to examine the possibility that SSM and NM are the result of independent pathways characterized by unique molecular alterations. Cell lines including SSM, NM, metastatic melanoma, and melanocyte controls were evaluated for copy number changes and differential mRNA expression using single nucleotide polymorphism array (SNP 6.0, Affymetrix) and gene array (U133A 2.0, Affymetrix). Data sets were integrated to identify copy number alterations that correlated with gene expression, and array results were validated using immunohistochemistry on human tissue microarrays (TMAs) and an external data set. The functional effect of genomic deletion was assessed by lentiviral overexpression. Integrative genomics revealed 8 genes in which NM/SSM-specific copy number alterations were correlated with NM/SSM differential gene expression (P<0.05, Spearmans rank). Pathways analysis of differentially expressed genes (N=114) showed enrichment for metabolic-related processes. SSM-specific genomic deletions (DIS3, MTAP, G3BP2, SEC23IP, USO1) were verified in an expanded panel of cell lines, and forced overexpression of MTAP in SSM resulted in reduced cell growth. Metabolism-related gene ALDH7A1 was verified as overexpressed in NM using human TMAs.The identification of recurrent genomic deletions in SSM not present in NM challenges the linear model of melanoma progression and supports the unique molecular classification of SSM and NM.
Integrative genomics identifies molecular alterations that challenge the linear model of melanoma progression.
Cell line
View SamplesAlternative mRNA splicing is an important mechanism for regulation of gene expression. Changes in gene expression contribute to the pathogenesis of heart failure. However, changes in mRNA splicing have not been systematically examined in heart disease. We hypothesized that mRNA splicing is changed in diseased hearts.
Heart failure-associated changes in RNA splicing of sarcomere genes.
No sample metadata fields
View SamplesThe scaffold attachment factors SAFB1 and SAFB2 are paralogs, which are involved in cell cycle regulation, apoptosis, differentiation, and stress response. They have been shown to function as estrogen receptor co-repressors, and there is evidence for a role in breast tumorigenesis. To identify their endogenous target genes in MCF-7 breast cancer cells, we utilized gene expression array analysis, which was set up in a two-by-four design, with vehicle and estrogen treatment, and control, SAFB1, SAFB2, and SAFB1/SAFB2 siRNA as variables. Using custom chips containing 1.5 kb upstream regulatory region, we identified 541 SAFB1/SAFB2 binding sites in promoters of known genes, with significant enrichment on chromosome 1 and 6. Gene expression analysis revealed that the majority of target genes were induced in the absence of SAFB1 or SAFB2, and less were repressed. In contrast to SAFB2, which shared most of its target genes with SAFB1, SAFB1 had many unique target genes, most of them involved in regulation of the immune system. A subsequent analysis of the estrogen treatment group revealed that twelve percent of estrogen-regulated genes were dependent on SAFB1, with the majority being estrogen-repressed genes. These were primarily genes involved in apoptosis, such as BBC3, NEDD9, and OPG. Thus, this study confirms SAFB1/SAFB2s primary role as co-repressors, and also uncovers a previously unknown role for SAFB1 in regulation of immune genes, and in estrogen-mediated repression of genes.
SAFB1 mediates repression of immune regulators and apoptotic genes in breast cancer cells.
Cell line, Treatment
View SamplesObstructive sleep apnea (OSA) leads to increased cardiovascular morbidity and mortality, which have been attributed to intermittent hypoxia (IH). The effects of IH on lung structure and function are unknown. We used a mouse model of chronic IH, which mimics the O2 profile in patients with OSA. We exposed adult C57BL/6J mice to 3 months of IH with an FIO2 nadir of 5%, 60 times/hr during the 12hr light phase. Control mice were exposed to room air.
Chronic intermittent hypoxia induces lung growth in adult mice.
Sex, Specimen part
View SamplesThe undifferentiated spermatogonial population of mouse testis is known to be functionally heterogeneous and contain both stem cells and committed progenitor cells. However, gene expression patterns marking these distinct cell fractions are poorly defined. We found that a subset of undifferentiated spermatogonia were marked by expression of a PDX1-GFP transgene but properties of these cells were unclear. Undifferentiated cells were therefore isolated from adult testes and separated according to expression of PDX1-GFP+ for gene expression analysis by RNA-seq. Our goal was to identify differentially expressed genes from PDX1-GFP+ vs PDX1-GFP- with that of known markers of stem and committed progenitor cells. Overall design: 4 independent sets of PDX1-GFP-positive and PDX1-GFP-negative undifferentiated spermatogonia were isolated by flow sorting from adult mouse testes.
Identification of dynamic undifferentiated cell states within the male germline.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Zebrafish Pou5f1-dependent transcriptional networks in temporal control of early development.
No sample metadata fields
View SamplesSynthetic DNA-binding proteins have found broad application in gene therapies and as tools for interrogating biology. Engineered proteins based on the CRISPR/Cas9 and TALE systems have been used to alter genomic DNA sequences, control transcription of endogenous genes, and modify epigenetic states. Although the activity of these proteins at their intended genomic target sites have been assessed, the genome-wide effects of their action have not been extensively characterized. Additionally, the role of chromatin structure in determining the binding of CRISPR/Cas9 and TALE proteins to their target sites and the regulation of nearby genes is poorly understood. Characterization of the activity these proteins using modern high-throughput genomic methods would provide valuable insight into the specificity and off-target effects of CRISPR- and TALE-based genome engineering tools. We have analyzed the genome-wide effects of TALE- and CRISPR-based transcriptional activators targeted to the promoters of two different endogenous human genes in HEK293T cells using a variety of high-throughput DNA sequencing methods. In particular, we assayed the DNA-binding specificity of these proteins and their effects on the epigenome. DNA-binding specificity was evaluated by ChIP-seq and RNA-seq was used to measure the specificity of these activators in perturbing the transcriptome. Additionally, DNase-seq was used to identify the chromatin state at target sites of the synthetic transcriptional activators and the genome-wide chromatin remodeling that occurs as a result of their action. Our results show that these genome engineering technologies are highly specific in both binding to their promoter target sites and inducing expression of downstream genes when multiple activators bind to a single promoter. Moreover, we show that these synthetic activators are able to induce the expression of silent genes in heterochromatic regions of the genome by opening regions of closed chromatin and decreasing DNA methylation. Interestingly, the transcriptional activation domain was not necessary for DNA-binding or chromatin remodeling in these regions, but was critical to inducing gene expression. This study shows that these CRISPR- and TALE-based transcriptional activators are exceptionally specific. Although we detected limited binding of off-target sites in the genome and changes to genome structure, these off-target event did not lead to any detectable changes in gene regulation. Collectively, these results underscore the potential for these technologies to make precise changes to gene expression for gene and cell therapies or fundamental studies of gene function. Overall design: HEK293T cells were transfected in triplicate with plasmids expressing synthetic transcription factors. The synthetic TFs were either (a) dCas9-VP64 fusion protein and a targeting guide RNA (gRNA), or (b) a TALE-VP64 fusion protein engineered to bind to a specific target site in the genome. As a control, cells were transfected with plasmids expressing GFP. After transfection, RNA-seq was used to identify both on-target and off-target binding sites for the synthetic TFs. The data in this submission were generated using the TALE transfection experiments.
Genome-wide specificity of DNA binding, gene regulation, and chromatin remodeling by TALE- and CRISPR/Cas9-based transcriptional activators.
No sample metadata fields
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