High-Throughput Sample Preparation from Whole Blood for Gene Expression Analysis

Whole blood is an attractive sample source for nucleic acid-based assays because it is readily available, easily accessible, and rich in genetic information. However, globin mRNA accounts for up to 70% of the mRNA (by mass) in whole blood total RNA, resulting in distortion of the RNA amplification and subsequently causing decreased Present calls, decreased call concordance, and increased signal variation in microarray analysis. Therefore, for gene expression analysis, whole blood is typically fractionated before total RNA isolation to reduce globin mRNA content. We have developed a high-throughput sample preparation technology that streamlines workflows for (1) total RNA isolation from whole blood (MagMAX-96 Blood RNA Isolation Kit), (2) globin mRNA removal using a novel, nonenzymatic technology (GLOBINclear—Human Kit), and (3) mRNA amplification and labeling for expression analysis (MessageAmp II-96 aRNA Amplification Kit). Globin mRNA removal eliminates the need for prefractionation of whole blood, minimizing the potential for expression profile changes during sample handling. Quantitative RT-PCR showed that this method effectively removed up to 95% of the globin mRNA from the isolated RNA while retaining normal levels of other mRNAs. The streamlined sample preparation enables quick and accurate expression analysis of relatively high numbers of blood samples.