Isolation of 5' flanking region of the fruit-specific gene wml1 from watermelon by Uneven PCR

The 5' flanking region of ADP-Glucose Pyrophosphorylase large subunit gene wml1, which covers 1864 bp, was isolated from watermelon genomic DNA by Uneven PCR. Sequence analysis indicated that there were putative TATA box and CAAT box at position 1237bp and 1284bp of the cloned fragment, respectively. Two transcriptional fusions between 5' regulational sequence of wml1 and beta-glucuronidase gene were constructed. Constructs containing 180bp-1752bp fragment could drive GUS gene transient express specifically in watermelon fruit, while 958bp-1752bp had no promoter activity. Putative fruit-specific cis-acting elements may locate between 180bp and 958bp.