Functional identity of genes detectable in expression profiling assays following globin mRNA reduction of peripheral blood samples

Objectives: Whole-blood RNA for microarray analysis is easily accessible but contains a large proportion of globin mRNA that interferes with the accurate assessment of other genes. This study investigated the biological significance of genes whose expression was unmasked by globin mRNA reduction in peripheral blood. Design and methods: Samples were collected from healthy subjects using the PAXgene Blood RNA System, and globin mRNA was depleted using GLOBINclear. Genes exhibiting consistent changes in expression on Affymetrix HU133A 2.0 arrays were characterized in three main areas of gene ontology — molecular function, biological process, and cellular component. Results: Globin reduction permitted detection of 2652 ± 395 additional genes per assay. Genes unmasked by globin reduction include low abundance transcripts that function primarily as molecular binding proteins and catalytic enzymes in biological processes including transcription, replication, and intracellular transport and signalling. Protein products of these genes are preferentially associated with membranes and the nucleus. Conclusions: Additional genes detectable only after globin reduction in whole-blood RNA function in a variety of biological processes that may be important to diverse fields of study.