string: Alternatively, ROS production may result from changes in gene expression that occur in the absence of eIF2a phosphorylation, such as reduced expression of genes encoding antioxidant functions (Sod2, Ucp2, and Pparg) (Brand and Esteves, 2005; Jo et al., 2006) or increased expression of genes that function in TNFa signaling (Tnfa, Tnfr1, A20, and p21) and contribute to ROS production (O’Reilly, 2005; Xue et al., 2005).