Activation of lacZ reporter gene
transcription by AP-1 acting alone and in cooperation with NFAT.
(A) Structure of the AP-1 bZIP domain (22), with functional
domains denoted, bound to a consensus AP-1 site. (B) NFAT,
bound to a polypurine tract in ARRE2, cooperatively recruits AP-1 to
the adjacent nonconsensus AP-1 site, thereby activating reporter gene
expression. AD denotes the B42 activation domain, which is fused to the
basic region of Fos. (C) AP-1-driven reporter assay detects
the binding of AP-1 alone to a consensus site in yeast. (D)
ARRE2-linked reporter assay detects the reconstitution of the
cooperative AP-1/NFAT/ARRE2 complex in yeast. Transcriptional
activity refers to units of β-galactosidase activity.