APRIL stimulates NF-κB-mediated HoxC4 induction for AID expression in mouse B cells

► APRIL induces HoxC4 and AID mRNA expression in mouse B cells. ► APRIL increases HoxC4 promoter activity in mouse B cells. ► Second NF-κB-binding element (NBE2) is essential for the HoxC4 promoter activation. ► APRIL enhances binding of NF-κB to the HoxC4 promoter NBE2 region. ► Overexpression of NF-κB increases APRIL-induced HoxC4 promoter activity.