Gel retardation assay of CArG boxes in the ripening-induced gene promoters. Gel retardation assay of possible CArG boxes (A) and atypical CArG boxes (B) found in the promoters of the ripening-induced genes. DNA fragments of putative RIN-binding sites that contain a normal CArG-box sequence and flanking regions shown in Table 1 were reacted with the RIN-MIK protein in vitro and electrophoresed (lanes N). DNA fragments with mutations within the CArG box were also examined (lanes M). The normal CArG-box sequences (10 bp) and their mutant sequences are displayed below the gel images. Nucleotides substituted between the normal and mutated sequences are indicated by bold letters. The same amount of DNA fragments was applied to each lane in A and B. The image of B was adjusted to higher contrast than that of A due to the low intensities of the retarded signals for the sequences examined in B.