CYCLOPHILIN-A AND FKBP12 INTERACT WITH YY1 AND ALTER ITS TRANSCRIPTIONAL ACTIVITY

YY1 is a zinc finger transcription factor with unusual structural and functional features. In a yeast two-hybrid screen, two cellular protei ns, cyclophilin A (CyPA) and FK506-binding protein 12 (FKBP12), intera cted with YY1. These interactions are specific and also occur in mamma lian cells. Cyclosporin A and FK506 efficiently disrupt the YY1-CyPA a nd YY1-FKBP12 interactions. Overexpression of human CyPA and FKBP12 ha ve different effects on YY1-regulated transcription with these effects being promoter-dependent. These results suggest that immunophilins ma y be mediators in the functional role of YY1.