FIG. 1.

Expression of UPR target genes in HEK293 and N2a cells treated with tunicamycin. HEK293 and N2a cells were treated with 2 μg of tunicamycin/ml for the indicated periods. Total RNA isolated from the cells was subjected to RT-PCR with specific primers, and products were analyzed on polyacrylamide gels. (A) The levels of established UPR target genes: BiP, CHOP, GADD45, and Mif 1. β-actin mRNA served as the control. For the negative control (lanes −), RT-PCR was performed in the absence of reverse transcriptase. (B) Upregulation of UPR genes that regulate Ca²⁺ homeostasis: ATP2A2, NUCB2, CGRP2, and STC2.