Detection of Unfolded Protein Response by Polymerase Chain Reaction.

The unfolded protein response is a cellular adaptive mechanism localized in the endoplasmic reticulum. It involves three phases: the detection of increased presence of unfolded proteins as a result of cellular stressors; the execution of an adaptive cascade of events aimed at the enhancement of proper protein folding and degradation of improperly folded proteins; and finally, when stress is not alleviated, the execution of programmed cell death. The main effectors of the UPR are transcription factors involved in the upregulation of either chaperone proteins or proapoptotic proteins. Two of these transcription factors are CHOP and the spliced variant of XBP-1 (XBP1s). In this chapter, we describe a quantitative PCR method to detect the upregulation of CHOP and XBP1s mRNA during Tunicamycin-induced UPR.