Selection of Reference Genes for Gene Expression Studies in Porcine Whole Blood and Peripheral Blood Mononuclear Cells under Polyinosinic:Polycytidylic Acid Stimulation

Wang, Jiying; Wang, Yanping; Wang, Huaizhong; Hao, Xiaojing; Wu, Ying; Guo, Jianfeng

real-time PCR (qRT-PCR) can simultaneously measure gene expression in many different samples for a limited number of genes, and is especially suitable when only a small number of cells are available. It has become the standard method for quantification of gene expression studies. In case of qRT-PCR, the use of reference genes as internal controls is the most common method for normalizing mRNA data (Huggett et al., 2005) . The reference gene is a stably expressed gene that is experimentally verified in given species and tissues under given experimental conditions. However, an increasing number of reports have shown that the expression of some frequently used internal reference genes may vary significantly under different experimental conditions (Vandesompele et al., 2002; Nygard et al., 2007; Facci et al., 2011) . If the chosen reference gene has a large expression fluctuation among samples tested, the normalization will lead to erroneous gene expression profiles of the target gene of interest. Therefore, the selection of the most stable gene or set of genes as internal controls is a critical step to control the variability among samples for quantitative gene expression studies with a sensitive qRT-PCR technique.