Unexpected presence of mycoplasma probes on human microarrays

Mycoplasma and Microarray Mycoplasma contamination of cultured cells alters gene expression by adversely affecting cellular physiology. Because the presence of mycoplasma in cultures can be difficult to detect, contaminated cell lines may unintentionally be used in microarray evaluation, leading to confounded data analysis and erroneous conclusions regarding the patterns of gene expression. In a letter to the editor, M. Arno and colleagues at King's College London describe their identification of a probeset on the Affymetrix HG-U133 Plus 2.0 human microarray (1570561_at) that unexpectedly mapped to the 16S–23S intergenic transcribed spacer (ITS) region of multiple mycoplasma species. This sequence was originally submitted as an unknown Homo sapiens expressed sequence tag acquired during a full-length cDNA sequencing project, which the authors suspect might explain its inclusion on the human microarray. FASTA alignments of all other target sequences contained on the array showed that only this probeset map...