Exposure to environmental contaminants can disrupt normal development of the early vertebrate skeleton. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) impairs craniofacial skeletal development across many vertebrate species and its effects are especially prominent in early life stages of fish. TCDD activates the aryl hydrocarbon receptor (AHR), a transcription factor that mediates most if not all TCDD responses. We investigated the transcriptional response in the developing zebrafish jaw following TCDD exposure using DNA microarrays. Zebrafish larvae were exposed to TCDD at 96 h postfertilization (hpf) and jaw cartilage tissue was harvested for microarray analysis at 1, 2, 4 and 12 h postexposure (hpe). Numerous chondrogenic transcripts were misregulated by TCDD in the jaw. Comparison of transcripts altered by TCDD in jaw with transcripts altered in embryonic heart showed that the transcriptional responses in the jaw and the heart were strikingly different. Sox9b, a critical chondrogenic transcription factor, was the most significantly reduced transcript in the jaw. We hypothesized that the TCDD reduction of sox9b expression plays an integral role in affecting formation of the embryonic jaw. Morpholino knock down of sox9b expression demonstrated that partial reduction of sox9b expression alone was sufficient to produce a TCDD-like jaw phenotype. Heterozygous sox9b deletion mutant embryos were sensitized to TCDD. Lastly, embryos injected with sox9b mRNA and then exposed to TCDD blocked TCDD-induced jaw toxicity in approximately 14% of sox9b-injected embryos. These results suggest that reduced sox9b expression in TCDD-exposed zebrafish embryos contributes to jaw malformation.
Aryl hydrocarbon receptor-mediated down-regulation of sox9b causes jaw malformation in zebrafish embryos.
No sample metadata fields
View SamplesMicroarray anlaysis was performed to investigate gene expression patterns of other transcription factors involved in early retinal and/or forebrain development using human embryonic stem cell-derived retinal and forebrain progenitor cells. After 20 days of differentiation, vesicular neurospheres selectively expressed multiple retinal transcription factor genes appropriate for the OV stage of retinogenesis, whereas nonvesicular neurospheres expressed transcription factors indicative of the embryonic forebrain. Many transcription factor genes associated with retinal development were present at higher levels in vesicular vs. nonvesicular neurospheres. Nonvesicular neurospheres, on the other hand, expressed higher levels of transcription factors implicated in early forebrain development. Taken together, results indicated that the vesicular and nonvesicular neurospheres harbored retinal progenitor cells and early forebrain populations, respectively.
Optic vesicle-like structures derived from human pluripotent stem cells facilitate a customized approach to retinal disease treatment.
Specimen part
View SamplesTranscriptomic studies revealed that hundreds of mRNAs show differential expression in the brains of sleeping versus awake rats, mice, flies, and sparrows. Although these results have offered clues regarding the molecular consequences of sleep and sleep loss, their functional significance thus far has been limited. This is because the previous studies pooled transcripts from all brain cells, including neurons and glia.
Effects of sleep and wake on oligodendrocytes and their precursors.
Specimen part
View SamplesTranscriptomic studies revealed that hundreds of mRNAs show differential expression in the brains of sleeping versus awake rats, mice, flies, and sparrows. Although these results have offered clues regarding the molecular consequences of sleep and sleep loss, their functional significance thus far has been limited. This is because the previous studies pooled transcripts from all brain cells, including neurons and glia.
Transcriptome profiling of sleeping, waking, and sleep deprived adult heterozygous Aldh1L1 - eGFP-L10a mice.
Disease
View SamplesCoordinated regulation of gene expression levels across a series of experimental conditions provides valuable information about the functions of correlated transcripts. To map gene regulatory pathways, we used microarray-derived gene expression measurements in 60 individuals of an F2 sample segregating for diabetes. We performed correlation analysis among ~40,000 expression traits. By combining correlation among expression traits and linkage mapping information, we were able to identify regulatory networks, make functional predictions to uncharacterized genes, and characterize novel members of known pathways. Using 36 seed traits, we found evidence of coordinate regulation of 160 G-protein coupled receptor (GPCR) pathway expression traits. Of the 160 traits, 50 had their major LOD peak within 8 cM of a locus on chromosome 2, and 81 others had a secondary peak in this region. A previously uncharacterized Riken cDNA clone, which showed strong correlation with stearoyl CoA desaturase 1 expression, was experimentally validated to be responsive to conditions that regulate lipid metabolism. Using linkage mapping, we identified multiple genes whose expression is under the control of transcription regulatory loci. Trait-correlation combined with linkage mapping can reveal regulatory networks that would otherwise be missed if we only studied mRNA traits with statistically significant linkages in this small cross. The combined analysis is more sensitive compared with linkage mapping only.
Combined expression trait correlations and expression quantitative trait locus mapping.
No sample metadata fields
View SamplesHuman papillomaviruses (HPVs) are associated with nearly all cervical cancers (CCs), 20-30% of head and neck cancers (HNCs), and other cancers. Because HNCs also arise in HPV-negative patients, this type of cancer provides unique opportunities to define similarities and differences of HPV-positive versus HPV-negative cancers arising in the same tissue. Here, we describe genome-wide expression profiling of 84 HNCs, CCs and site-matched normal epithelial samples in which we used laser capture microdissection to enrich samples for tumor-derived versus normal epithelial cells. This analysis revealed that HPV+HNCs and CCs differed in their patterns of gene expression yet shared many changes compared to HPV-HNCs. Some of these shared changes were predicted, but many others were not. Notably, HPV+HNCs and CCs were found to be upregulated in their expression of a distinct and larger subset of cell cycle genes than observed in HPV-HNC. Moreover, HPV+ cancers over-expressed testis-specific genes that are normally expressed only in meiotic cells. Many, though not all, of the hallmark differences between HPV+HNC and HPV-HNC were a direct consequence of HPV and in particular the viral E6 and E7 oncogenes. This included a novel association of HPV oncogenes with testes specific gene expression. These findings in primary human tumors provide novel biomarkers for early detection of HPV+ and HPV- cancers, and emphasize the potential value of targeting E6 and E7 function, alone or combined with radiation and/or traditional chemotherapy, in the treatment of HPV+ cancers.
Fundamental differences in cell cycle deregulation in human papillomavirus-positive and human papillomavirus-negative head/neck and cervical cancers.
Sex, Age
View SamplesRetinoic acid (RA) and 2,3,7,8-tetrachlorodibenzo-p-dioxin activate distinct ligand-dependent transcription factors, and both cause cardiac malformation and heart failure in zebrafish embryos. We hypothesized that they cause this response by hyperactivating a common set of genes critical for heart development. To test this, we used microarrays to measure transcripts changes in hearts isolated from zebrafish embryos 1,2,4 and 12 h after exposure to 1M RA. We used hierarchical clustering to compare the transcriptional responses produced in the embryonic heart by RA and TCDD. We could identify no early responses in common between the two agents. However, at 12 h both treatments produced a dramatic downregulation of a common cluster of cell cycle progression genes, which we term the Cell Cycle Gene Cluster (CCGC). This was associated with a halt in heart growth. These results suggest that RA and TCDD ultimately trigger a common transcriptional response associated with heart failure, but not through the direct activation of a common set of genes. Among the genes rapidly induced by RA was Nr2F5, a member of the COUP-TF family of transcription repressors. We found that induction of Nr2F5 was both necessary and sufficient for the cardiotoxic response to RA.
Comparative genomics identifies genes mediating cardiotoxicity in the embryonic zebrafish heart.
No sample metadata fields
View SamplesNasopharyngeal carcinoma is an Epstein-Barr virus-associated epithelial cancer with high prevalence in Southeast Asia. mRNA expression levels were measured for essentially all human genes and all latent Epstein-Barr virus (EBV) genes in nasopharyngeal carcinoma tissue samples and normal nasopharyngeal tissues. Data were analyzed for differential gene expression between tumor and normal tissue and for correlations with levels of viral gene expression. Primary publications: Sengupta et al, 2006, Cancer Research 66(16): 7999-8006. Dodd et al, 2006, Cancer Epidemiology, Biomarkers & Prevention 15(11): 2216-2225.
Genes involved in DNA repair and nitrosamine metabolism and those located on chromosome 14q32 are dysregulated in nasopharyngeal carcinoma.
No sample metadata fields
View SamplesFOG-1/CPEB and FOG-3/Tob are the terminal regulators of the sex determination in C. elegans germ cells. CPEB and Tob proteins are both translational regulators. To investigate how FOG-1 and FOG-3 regulate germ cell sex determination we sought to identify the target mRNAs. We used transgenic epitope tagged animals (3xMyc::FOG-1 and FOG-3::3xFLAG). To identify the mRNA targets of FOG-1/CPEB and FOG-3/Tob on a genome wide scale we used RNA immunoprecipitation followed by microarray analysis. We found 81 putative mRNA targets of FOG-1 and 722 putative targets of FOG-3. 76 target mRNAs were common to both FOG-1 and FOG-3.
Genomic Analyses of Sperm Fate Regulator Targets Reveal a Common Set of Oogenic mRNAs in Caenorhabditis elegans.
Specimen part
View SamplesGene expression profiles of a single Arabidopsis genotype (Col-0) in response to isogenic Pseudomonas syringae strains expressing one of four different cloned avr genes was studied (avrRpt2, avrRpm1, avrPphB, avrRps4; responses mediated by the R genes RPS2, RPM1, RPS5 and RPS4 ).
Discovery of ADP-ribosylation and other plant defense pathway elements through expression profiling of four different Arabidopsis-Pseudomonas R-avr interactions.
Age, Specimen part, Disease, Disease stage
View Samples