Genome wide mapping of the haematopoietic system transcriptome

Recent advances in high density oligonucleotides microarray technology have brought solutions for molecular profiling of human samples at an unprecedented resolution. We mapped whole blood RNA from healthy volunteers and CD34+ from cytapheresis to Human Exon ST 1.0 microarrays. We compared mature blood cells samples with immature CD34+ samples and each of these compartiement with a broad panel of solid tissues. By scanning the expression of over one million known or predicted exons, transcripts such as INPP4B, NEDD9 CD74 and VAV3 were identified as alternatively transcribed between haematopoietic system and solid tissues. The very large combinatorial complexity conveyed by alternative splicing contributes to the specific functional properties of blood cells and haematopoietic stem cells. The gene expression profiles are freely accessible through a dynamic web atlas, providing to the medical and scientific community a simple mean to interrogate and visualize this reference dataset. Finally, the relevance and the precision provided by this exon expression map suggest that exon arrays may be a powerful tool to link specific peripheral whole blood exon signatures modifications to many diseases such as cancer or auto-immune disorders. We analyzed 4 whole blood samples from healthy subjects and 3 CD34+ cells samples from cytapheresis using the Affymetrix Human Exon 1.0 ST microarray