HSPA1B and infection: On the other hand, contrasting to the bulk RNA-seq analysis, where the intermediate NS1 level during IAV-NS1-T infection still permitted UPR activation (Figure 2B), infection by IAV-WT with an intermediate level of NS1 (NS1-mid) did not robustly activate UPR (e.g., the lack of upregulations of heat shock proteins HSPA1A, HSPA1B, or DNAJB1 in Figure 4E).