Random monoallelic expression in the mouse: SNP array data

Random monoallelic expression is defined by the allele-specific expression of genes, and by the fact that for an individual cell this monoallelic expression is neither obligate nor necessarily coordinated with the allelic expression in other cells. In order to find novel examples of random monoallelic expression in mouse, we did a transcriptome-wide survey of allele-specific gene expression in two different immortalized cell types. Lymphoblast cell lines and fibroblast cell lines were established (both clonal and nonclonal) and were used as a source of both nuclear RNA and genomic DNA. These samples were assessed for allele-specific gene expression using a custom-designed Mouse SNP Chip. A large number of genes (over 10% of those that were assessed in lymphoblast clones) displayed random monoallelic expression. For each cell line, two replicate samples of ds-cDNA were assessed for monoallelic expression, while genomic DNA was assessed as a control for possible LOH events. Nonclonal samples were used as controls for cis-acting allelic bias.