In the present study, we examined the hepatic transcriptome of chickens during the peri-hatch periodor the metabolic jump from chorioallantoic (embryo) to pulmonary (hatchling) respiration. Although our major interest was comparison of differentially-expressed genes between embryos and hatchlings, we made pairwise contrasts across six developmental ages. We collected the liver from four embryos at three ages (e16, e18 and e20) and four hatchling chicks at three ages (1, 3 and 9 days) post hatching. Liver samples (N=24) were used for extraction of total RNA which was then used for hybridization to 24 Affymetrix Chicken Genome Arrays. Ingenuity Pathways Analysis was used for functional annotation and mapping of differentially expressed (FDR0.05) genes to canonical pathways and gene interaction networks. We identified 1274 hepatic genes that were differentially expressed between embryos and hatchling chicks and of these, 284 genes are involved in lipid metabolism. The three most abundant found in liver of embryos were (MOGAT1, DIO3 and PDK4), whereas THRSP, FASN and DIO2 were greatly expressed in liver of hatchlings. Two functionally-distinct clusters of hepatic genes have emerged from our time-course transcriptional scans in the peri-hatch chicken. Cluster A genes are largely lipolytic with higher expression in the embryo, while Cluster B genes are mainly lipogenic and thermogenic with greater expression in liver of hatchlings. The present study describes the innate chorography of transcriptional responses of liver to the abrupt metabolic switch from aquatic ectothermy (embryos) to free-living endothermy (hatchling chicks).
Transcriptional profiling of liver during the critical embryo-to-hatchling transition period in the chicken (Gallus gallus).
Sex, Specimen part
View SamplesWe performed microarray analysis on ISCU myopathy patient muscle biopsies to identify transcriptional modulation of pathways involved in the cellular response to Fe-S cluster deficiency.
Elevated FGF21 secretion, PGC-1α and ketogenic enzyme expression are hallmarks of iron-sulfur cluster depletion in human skeletal muscle.
Sex, Specimen part
View SamplesThe most important approach to the development of platform organisms for recombinant protein production relies on random mutagenesis and phenotypic selection. Complex phenotypes, including those associated with significant elevated expression and secretion of heterologous proteins, are the result of multiple genomic mutations. Using next generation sequencing, a parent and derivative hypersecreter strain (B41) of Escherichia coli were sequenced with an average coverage of 52.8X and 55X, respectively. A new base-pair calling program, revealed a single nucleotide polymorphism in the B41 genome at position 1,074,787, resulting in translation termination near the N-terminus of a transcriptional regulator protein, RutR, coded by the ycdC gene. We verified the hypersecretion phenotype in a ycdC::Tn5 mutant and observed a 3.4-fold increase in active hemolysin secretion, consistent with the increase observed in B41. mRNA expression profiling showed decreased expression of tRNA-synthetases and some amino acid transporters in the ycdC::Tn5 mutant. This study demonstrates that power of next generation sequencing to characterize mutants leading to successful metabolic engineering strategies for strain improvement.
A single nucleotide polymorphism in ycdC alters tRNA synthetase expression and results in hypersecretion in Escherichia coli.
No sample metadata fields
View SamplesOne of the major players controlling RNA decay is the cytoplasmic 5'-to-3' exoribonuclease, which is conserved among eukaryotic organisms. In Arabidopsis, the 5'-to-3' exoribonuclease XRN4 is involved in disease resistance, the response to ethylene, RNAi, and miRNA-mediated RNA decay. Curiously, XRN4 appears to display selectivity among its substrates because certain 3' cleavage products formed by miRNA-mediated decay, such as from ARF10 mRNA, accumulate in the xrn4 mutant, whereas others, such as from AGO1, do not. To examine the nature of this selectivity, transcripts that differentially accumulate in xrn4 were identified by combining PARE and Affymetrix arrays. Certain functional categories, such as stamen-associated proteins and hydrolases, were over-represented among transcripts decreased in xrn4, whereas transcripts encoding nuclear-encoded chloroplast-targeted proteins and nucleic acid-binding proteins were over-represented in transcripts increased in xrn4. To ascertain if RNA sequence influences the apparent XRN4 selectivity, a series of chimeric constructs was generated in which the miRNA-complementary sites and different portions of the surrounding sequences from AGO1 and ARF10 were interchanged. Analysis of the resulting transgenic plants revealed that the presence of a 150 nucleotide sequence downstream from the ARF10 miRNA-complementary site conferred strong accumulation of the 3' cleavage products in xrn4. In addition, sequence analysis of differentially accumulating transcripts led to the identification of 27 hexamer motifs that were over-represented in transcripts or miRNA-cleavage products accumulating in xrn4. Taken together, the data indicate that specific mRNA sequences, like those in ARF10, and mRNAs from select functional categories are attractive targets for XRN4-mediated decay.
Evidence that XRN4, an Arabidopsis homolog of exoribonuclease XRN1, preferentially impacts transcripts with certain sequences or in particular functional categories.
Specimen part
View SamplesConsider the problem of designing a panel of complex biomarkers to predict a patient's health or disease state when one can pair his or her current test sample, called a target sample, with the patient's previously acquired healthy sample, called a reference sample. As contrasted to a population averaged reference, this reference sample is individualized. Automated predictor algorithms that compare and contrast the paired samples to each other could result in a new generation of test panels that compare to a person's healthy reference to enhance predictive accuracy. This study develops such an individualized predictor and illustrates the added value of including the healthy reference for design of predictive gene expression panels. The objective is to predict each subject's state of infection, e.g., neither exposed nor infected, exposed but not infected, pre-acute phase of infection, acute phase of infection, post-acute phase of infection. Using gene microarray data collected in a large-scale serially sampled respiratory virus challenge study, we quantify the diagnostic advantage of pairing a person's baseline reference with his or her target sample.
An individualized predictor of health and disease using paired reference and target samples.
Specimen part, Subject, Time
View SamplesAfrican-American individuals of the GENOA cohort
Genetic Architecture of Gene Expression in European and African Americans: An eQTL Mapping Study in GENOA.
Sex, Age, Specimen part
View SamplesThe NIH Roadmap Epigenomics Mapping Consortium aims to produce a public resource of epigenomic maps for stem cells and primary ex vivo tissues selected to represent the normal counterparts of tissues and organ systems frequently involved in human disease.
The NIH Roadmap Epigenomics Mapping Consortium.
Sex, Specimen part, Disease, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Innate immune activity is detected prior to seroconversion in children with HLA-conferred type 1 diabetes susceptibility.
Sex, Specimen part
View SamplesA cardinal symptom of Major Depressive Disorder (MDD) is the disruption of circadian patterns. Yet, to date, there is no direct evidence of circadian clock dysregulation in the brains of MDD patients. Circadian rhythmicity of gene expression has been observed in animals and peripheral human tissues, but its presence and variability in the human brain was difficult to characterize. Here we applied time-of-death analysis to gene expression data from high-quality postmortem brains, examining 24-hour cyclic patterns in six cortical and limbic regions of 55 subjects with no history of psychiatric or neurological illnesses ('Controls') and 34 MDD patients. Our dataset covered ~12,000 transcripts in the dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (AnCg), hippocampus (HC), amygdala (AMY), nucleus accumbens (NAcc) and cerebellum (CB). Several hundred transcripts in each region showed 24-hour cyclic patterns in Controls, and >100 transcripts exhibited consistent rhythmicity and phase-synchrony across regions. Among the top ranked rhythmic genes were the canonical clock genes BMAL1(ARNTL), PER1-2-3, NR1D1(REV-ERB), DBP, BHLHE40(DEC1), and BHLHE41(DEC2). The phasing of known circadian genes was consistent with data derived from other diurnal mammals. Cyclic patterns were much weaker in MDD brains, due to shifted peak timing and potentially disrupted phase relationships between individual circadian genes. This is the first transcriptome-wide analysis of cyclic patterns in the human brain and demonstrates a rhythmic rise and fall of gene expression in regions outside of the suprachiasmatic nucleus in control subjects. The description of its breakdown in MDD suggest novel molecular targets for treatment of mood disorders.
Circadian patterns of gene expression in the human brain and disruption in major depressive disorder.
Subject
View SamplesWith aging, significant changes in circadian rhythms occur, including a shift in phase toward a morning chronotype and a loss of rhythmicity in circulating hormones. However, the effects of aging on molecular rhythms in the human brain have remained elusive. Here we employed a previously-described time-of-death analyses to identify transcripts throughout the genome that have a significant circadian rhythm in expression in the human prefrontal cortex (Brodmanns areas (BA) 11 and 47). Expression levels were determined by microarray analysis in 146 individuals. Rhythmicity in expression was found in ~10% of detected transcripts (p<0.05). Using a meta-analysis across the two brain areas, we identified a core set of 235 genes (q<0.05) with significant circadian rhythms of expression. These 235 genes showed 92% concordance in the phase of expression between the two areas. In addition to the canonical core circadian genes, a number of other genes were found to exhibit rhythmic expression in the brain. Notably, we identified more than one thousand genes (1186 in BA11; 1591 in BA47) that exhibited age-dependent rhythmicity or alterations in rhythmicity patterns with aging. Interestingly, a set of transcripts gained rhythmicity in older individuals, which may represent a compensatory mechanism due to a loss of canonical clock function. Thus, we confirm that rhythmic gene expression can be reliably measured in human brain and identified for the first time significant changes in molecular rhythms with aging that may contribute to altered cognition, sleep and mood in later life.
Effects of aging on circadian patterns of gene expression in the human prefrontal cortex.
Sex, Age, Specimen part, Race
View Samples