Identification of preferred binding sites of a light-inducible DNA-binding factor (MNF1) within 5′-upstream sequence of C4-type phosphoenolpyruvate carboxylase gene in maize

摘要: MNF1 is a factor which specifically binds to 318 bp fragment (-1012 -695) in the 5′-flanking region of C4-type phosphoenolpyruvate carboxylase gene Zea mays (Yanagisawa et al., Mol Gen Genet 224 (1990) 325–332). The most preferred binding site determined by 2 mutation-scanning assay was an octamer sequence, GTGCCCTT, located within repeated sequences (RS1; -886 -849, -846 -807). Furthermore, PCR-mediated selection-amplification identified both GTGCCC(A/T)(A/T), and additional CC(G/A)CCC, latter similar Sp1 sites vertebrates. Specific each supposed confirmed with double-stranded monomers as probes. Considering native molecular mass (ca. 500 kDa), protein complex expected. In addition, anticipated have two distinct DNA-binding proteins since CCGCCC element 1,10-phenanthroline-dependent whereas independent. Wide distribution 1 kb promoter accounts for broad interactions MNF1. Moreover, specific DNA due MNF1, not observed nuclear extract derived from germinated cultivated plants darkness, appeared after white-light pulse. This finding suggests involvement light-dependent transcriptional control expression.