Project description:To assess the transcriptomic response of the LUAD cell line A549 to hypoxia, cells were exposed to 1% (Hx) or 21% O2 (Nx) during 24 hours. Two independent experiments were carried out.
Project description:To assess the transcriptomic response of the LUAD cell line A549 to hypoxia, cells were exposed to 1% (Hx) or 21% O2 (Nx) during 24 hours. Two µg of total RNAs were depleted from ribosomal RNA with the Ribozero kit (epicenter), libraries were generated with the NEBNext Small RNA Library Prep Set for SOLiD and sequenced on SOLiD 5500XL (Life Technologies) with single-end 50bp reads. Reads were aligned to the human genome release hg19 with the LifeScope software v2.5.1 (Life Technologies) using whole transcriptome pipeline for RNA‐seq libraries with default parameters.
Project description:BackgroundAs part of its broad and ambitious mission, the MicroArray Quality Control (MAQC) project reported the results of experiments using External RNA Controls (ERCs) on five microarray platforms. For most platforms, several different methods of data processing were considered. However, there was no similar consideration of different methods for processing the data from the Agilent two-color platform. While this omission is understandable given the scale of the project, it can create the false impression that there is consensus about the best way to process Agilent two-color data. It is also important to consider whether ERCs are representative of all the probes on a microarray.ResultsA comparison of different methods of processing Agilent two-color data shows substantial differences among methods for low-intensity genes. The sensitivity and specificity for detecting differentially expressed genes varies substantially for different methods. Analysis also reveals that the ERCs in the MAQC data only span the upper half of the intensity range, and therefore cannot be representative of all genes on the microarray.ConclusionAlthough ERCs demonstrate good agreement between observed and expected log-ratios on the Agilent two-color platform, such an analysis is incomplete. Simple loess normalization outperformed data processing with Agilent's Feature Extraction software for accurate identification of differentially expressed genes. Results from studies using ERCs should not be over-generalized when ERCs are not representative of all probes on a microarray.
Project description:SurePrint G3 Human Gene Expression 8x60k oligonucleotide microarrays (Design ID: 028004,Agilent) were used to characterize gene expression profiles of A549 cells exposed to different concentrations of HBCD (hexabromocyclododecane) for 24 hours.