Project description:The Affymetrix Human Exon 1.0 ST array was used to measure differential splicing patterns in archived RNA isolated from 26 of 80 children (11 Rejectors and 15 Non-Rejectors). The exon-level probe summaries reported in this series were computed using the Affymetrix Power Tools (APT) software and 'rma-sketch' normalization method. Keywords: Affymetrix 1.0 ST exon array; exon-level analysis
Project description:The Affymetrix Human Exon 1.0 ST array was used to measure differential splicing patterns in archived RNA isolated from 26 of 80 children (11 Rejectors and 15 Non-Rejectors). The gene-level probe summaries reported in this series were computed using the Affymetrix Power Tools (APT) software and 'rma-sketch' normalization method. Keywords: Affymetrix 1.0 ST exon array; gene-level analysis
Project description:The aim of the experiment was to evaluate the performance of the Affymetrix Brassica Exon 1.0 ST array. Root and leaf samples from Brassica rapa line R-O-18 were compared. The same RNA samples were hybridised to the Agilent Brassica array, to compare the performance of the two arrays.
Project description:This experiment accompanies the main analysis using a custom MHC array to define the first high-resolution, strand-specific transcriptional map of the MHC, defining differences in gene expression for three common haplotypes associated with autoimmune disease. Unstimulated samples for each haplotype were hybridised to Affymetrix Human Exon 1.0 ST arrays as well the custom MHC array. Exon array data were used to assess the concordance of signal obtained from the two platforms and to investigate the extent of alternative splicing in the MHC, and how it compares to the rest of the genome.
Project description:This experiment accompanies the main analysis using a custom MHC array to define the first high-resolution, strand-specific transcriptional map of the MHC, defining differences in gene expression for three common haplotypes associated with autoimmune disease. Unstimulated samples for each haplotype were hybridised to Affymetrix Human Exon 1.0 ST arrays as well the custom MHC array. Exon array data were used to assess the concordance of signal obtained from the two platforms and to investigate the extent of alternative splicing in the MHC, and how it compares to the rest of the genome. Lymphoblastoid cell lines carrying three common autoimmunity haplotypes (COX, PGF, QBL) were analysed in triplicate using the Affymetrix Human Exon 1.0 ST Array.
Project description:Background:Alternative splicing and isoform level expression profiling is an emerging field of interest within genomics. Splicing sensitive microarrays, with probes targeted to individual exons or exon-junctions, are becoming increasingly popular as a tool capable of both expression profiling and finer scale isoform detection. Despite their intuitive appeal, relatively little is known about the performance of such tools, particularly in comparison with more traditional 3’ targeted microarrays. Here, we use the well studied Microarray Quality Control (MAQC) dataset to benchmark the Affymetrix Exon Array, and compare it to two other popular platforms: Illumina, and Affymetrix U133. Results:We show that at the gene expression level, the Exon Array performs comparably with the two 3’ targeted platforms. However, the interplatform correlation of the results is slightly lower than between the two 3’ arrays. We show that some of the discrepancies stem from the RNA amplification protocols, e.g. the Exon Array is able to detect expression of non-polyadenylated transcripts. More importantly, we show that many other differences result from the ability of the Exon Array to monitor more detailed isoform-level changes; several examples illustrate that changes detected by the 3’ platforms are actually isoform variations, and that the nature of these variations can be resolved using Exon Array data. Finally, we show how the Exon Array can be used to detect alternative isoform differences, such as alternative splicing, transcript termination, and alternative promoter usage. We discuss the possible pitfalls and false positives resulting from isoform-level analysis. Conclusions:The Exon Array is a valuable tool that can be used to profile gene expression while providing important additional information regarding the types of gene isoforms that are expressed and variable. However, analysis of alternative splicing requires much more hands on effort and visualization of results in order to correctly interpret the data, and generally results in considerably higher false positive rates than expression analysis. One of the main sources of error in the MAQC dataset is variation in amplification efficiency across transcripts, which is not adequately corrected using existing statistical methods. We outline approaches to reduce such errors by filtering out potentially problematic data. This SuperSeries is composed of the SubSeries listed below.
Project description:Affymetrix exon array data were generated from total RNA that was isolated from localized Ewing sarcoma biopsy specimens. Expression of transcript summarized data was compared to data generated from normal stem cells and normal adult tissues.
Project description:Samples were taken from surgically resected tumor specimens/metastases from patients with colorectal cancer. The expression profiles were determined using the Affymetrix GeneChip Human Exon 1.0 ST Array version 2.