Involvement of c-Jun in transactivation of MMCP-7 promoter.

(A) The reporter plasmid containing the intact, mutated, or deleted AP-1 motif (pP7-185, pP7-185-AP-1-mut, or pP7-84, respectively) was cotransfected with effector plasmids to FMA/3 cells. The value of luciferase activity was divided by that obtained with the cotransfection of pP7-84 and pEF-BOS and was shown as relative luciferase activity. (B) Reduced expression of MMCP-7 gene by the overexpression of dominant negative form of c-Jun, TAM-67. Total RNA was extracted from MST cells (indicated as Original), MST cells overexpressing TAM-67, or MST cells overexpressing empty expression vector (indicated as Mock). The expression of MMCP-7 gene was examined with Northern blot analysis. (C) Binding of c-Jun to the AP-1 motif in the MMCP-7 promoter. The 5′-AGCTGTCCCTGGAGTCTGAGTCACCCATTTAGCT, designated as AP-1, was used as a probe (the AP-1 motif is underlined). The oligonucleotide mutated in the AP-1 motif (TGAGTCA to TGAGTTG) was designated as AP-1-mut (the mutated nucleotides are underlined). The excess amount of nonlabeled AP-1 or AP-1-mut was added as a competitor.