IL-1R–signaling components are expressed and functional in the midgestation AGM region and liver. (A) RT-PCR analysis performed to examine the expression of the IL-1Rs type I (Il1r1), the accessory receptor (Il1rap) and the receptor type II (Il1r2), and several downstream signaling components, including Map3k7ip2 (TAB2), Map3k7 (TAK1), Traf6, and Irak4, and the ligand IL-1β (Il1b) in the E10-E12 AGM region and E11-E12 FL. (B) Overview of the culture method used to study gene induction or IκB degradation in AGM tissues. Single-cell suspensions were made from E11 AGM tissues and cultured in 6-well plates overnight. The next day, cells were treated with IL-1β and harvested for RT-PCR analysis or IκB degradation studies. (C) Representative semiquantitative RT-PCR for the IL-1β target genes Junb and Sod2 (MnSOD) after stimulation of E11 AGM and liver single-cell suspensions with IL-1β (10 ng/mL) for 0, 30, 90, or 120 minutes. (D) Western blot showing rapid IκB degradation after IL-1β stimulation (10 ng/mL) of E12 liver cells (left panel) or 3T3 fibroblasts (right panel).