Comparative Gene expression analysis of 2fTGH cells expressing Wild type STAT2 vs S734A-STAT2 in response to IFN-α or TNF-α

STAT2 is an essential transcription factor in type I interferon (IFN) signaling. STAT2 is activated following exposure to IFN stimulation by phosphorylation at tyrosine-690. This post-translational modification permits the assembly and nuclear retention of the ISGF3 complex (consisting of STAT1/STAT2/IRF9) to drive gene transcription. We recently identified STAT2 to be serine phosphorylated in an IFN-dependent manner. The biological significance of these novel phosphorylation events in STAT2 remain to be elucidated. Thus far our data show that serine phosphorylation of STAT2 negatively regulates the biological effects of IFN. In an effort to understand the scope of STAT2 serine phosphorylation in IFN signaling, we conducted comparative microarray analysis to identify a collection of genes that are regulated by phosphorylated Ser734-STAT2 vs. unphosphorylated S734-STAT2 after IFN treatment. STAT2 null 2fTGH cells referred thereafter as U6A cells were used to stably restore expression of either mutant STAT2 with Serine 734 changed to Alanine (S734A, S7) or wild type (WT) STAT2. Cells were stimulated with medium, IFN-α or TNF-α for 4 hours. RNA was extracted and microarrray analysis performed.