High-throughput systems for gene expression profiling have been developed and matured rapidly through the past decade. Broadly, these can be divided into two categories: hybridization-based and sequencing-based approaches. With data from different technologies being accumulated, concerns and challenges are raised regarding data comparability and agreement across technologies. Within an ongoing large-scale cross-platform data comparison framework, we report here a comparison based on identical samples between one-dye DNA microarray platforms and MPSS (Massively Parallel Signature Sequencing). The DNA microarray platforms generally provided highly correlated data, while moderate correlations between microarrays and MPSS were obtained. Disagreements between the two types of technologies can be attributed to limitations inherent to both technologies. The variation found between pooled biological replicates underlines the importance of exercising caution in identification of differential expression, especially for the purposes of biomarker discovery. Based on different principles, hybridization-based and sequencing-based technologies should be considered complementary to each other, rather than competitive, and currently, both provide indispensable tools for transcriptome profiling.
Comparison of hybridization-based and sequencing-based gene expression technologies on biological replicates.
No sample metadata fields
View SamplesBackground: Friedreich ataxia, an autosomal recessive neurodegenerative and cardiac disease, is caused by abnormally low levels of frataxin, an essential mitochondrial protein. All Friedreich ataxia patients carry a GAA/TTC repeat expansion in the first intron of the frataxin gene, either in the homozygous state or in compound heterozygosity with other loss-of-function mutations. The GAA expansion inhibits frataxin expression through a heterochromatin-mediated repression mechanism. Histone modifications that are characteristic of silenced genes in heterochromatic regions occur at expanded alleles in cells from Friedreich ataxia patients, including increased trimethylation of histone H3 at lysine 9 and hypoacetylation of histones H3 and H4.
HDAC inhibitors correct frataxin deficiency in a Friedreich ataxia mouse model.
No sample metadata fields
View SamplesCaesarean-delivered preterm pigs were fed 3 d of parenteral nutrition followed by 2 d of enteral formula feeding. Antibiotics (n=11) or control saline (n=13) were given twice daily from birth to tissue collection at d 5. NEC-lesions and intestinal structure, function, microbiology and immunity markers were recorded.
Antibiotics modulate intestinal immunity and prevent necrotizing enterocolitis in preterm neonatal piglets.
Specimen part, Treatment
View SamplesBACKGROUND
Emmprin and survivin predict response and survival following cisplatin-containing chemotherapy in patients with advanced bladder cancer.
No sample metadata fields
View SamplesGene expression microarrays have made a profound impact in biomedical research. The diversity of platforms and analytical methods has made comparison of data from multiple platforms very challenging. In this study, we describe a framework for comparisons across platforms and laboratories. We have attempted to include nearly all the available commercial and in house platforms. Using probe sequences matched at the exon level improved consistency of measurements across the different microarray platforms compared to annotation-based matches. Generally, consistency was good for highly expressed genes, and variable for genes with lower expression values as confirmed by QRT-PCR. Concordance of measurements was higher between laboratories on the same platform than across platforms. We demonstrate that, after stringent pre-processing, commercial arrays were more consistent than in-house arrays, and by most measures, one-dye platforms were more consistent than two-dye platforms.
A sequence-oriented comparison of gene expression measurements across different hybridization-based technologies.
No sample metadata fields
View SamplesGene expression microarrays have made a profound impact in biomedical research. The diversity of platforms and analytical methods has made comparison of data from multiple platforms very challenging. In this study, we describe a framework for comparisons across platforms and laboratories. We have attempted to include nearly all the available commercial and in-house platforms. Using probe sequences matched at the exon level improved consistency of measurements across the different microarray platforms compared to annotation-based matches. Generally, consistency was good for highly expressed genes, and variable for genes with lower expression values as confirmed by QRT-PCR. Concordance of measurements was higher between laboratories on the same platform than across platforms. We demonstrate that, after stringent pre-processing, commercial arrays were more consistent than in-house arrays, and by most measures, one-dye platforms were more consistent than two-dye platforms.
A sequence-oriented comparison of gene expression measurements across different hybridization-based technologies.
No sample metadata fields
View SamplesProjection-dependent ribosome profling from mouse mPFC.
Molecular and Circuit-Dynamical Identification of Top-Down Neural Mechanisms for Restraint of Reward Seeking.
Specimen part
View SamplesUsing anti-Argonaute (anti-AGO) antibody co-immunoprecipitation, followed by microarray analyses and downstream bioinformatics, RIP-Chip experiments enable direct analyses of miRNA targets. The analyses support four major findings: (i) RIP-Chip studies correlated with total input mRNA profiling provides more comprehensive information than using either RIP-Chip or total mRNA profiling alone after miRNA transfections; (ii) new data confirm that miR-107 paralogs target coding sequence (CDS) of mRNA; (iii) biochemical and computational studies indicate that the 3 portion of miRNAs plays a role in guiding miR-103/7 to the CDS of targets; and (iv) there are major sequence-specific targeting differences between miRNAs in terms of CDS versus 3-untranslated region targeting, and stable AGO association versus mRNA knockdown. For detailed protocol and for full discussion of the results please see Nelson PT et al, Nucleic Acids Res. 2011 Oct;39(18):8163-72.
Specific sequence determinants of miR-15/107 microRNA gene group targets.
Specimen part, Disease, Cell line
View SamplesThe goal of this study is to identify downstream pathways, diagnostic markers, and potential therapeutic targets for IFS/CMN.
Mediators of receptor tyrosine kinase activation in infantile fibrosarcoma: a Children's Oncology Group study.
Specimen part
View SamplesCellular RNA levels are determined by transcription and decay rates, which are fundamental in understanding gene expression regulation. Measurement of these two parameters is usually performed independently, complicating analysis and introducing methodological biases that hamper direct comparison. Here, we present a simple approach of concurrent sequencing of S. cerevisiae polyA+ and polyA- RNA 3' ends to simultaneously estimate total RNA levels, transcription and decay rates from the same RNA sample. The transcription data generated correlate well with reported estimates and also reveal local RNA polymerase stalling and termination sites with high precision. Although the method by design uses brief metabolic labeling of newly synthesized RNA with 4-thiouridine, the results demonstrate that transcription estimates can also be gained from unlabeled RNA samples. These findings underscore the potential of the approach, which should be generally applicable to study a range of biological questions in diverse organisms. Overall design: RNA 3' end seq of total and 2min 4-thiouracil (4tU) labelled RNA from S. cerevisiae cells. Aliquots of RNA were directly subjected to pA+ RNA 3' end sequencing (noPap samples). A second aliquot was in vitro polyadenylated using E. coli poly(A) polymerase and ribodepleted before library preparation (xPap samples).
Simultaneous Measurement of Transcriptional and Post-transcriptional Parameters by 3' End RNA-Seq.
Cell line, Subject
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