Promoter structure and activity of type 1 rice metallothionein-like gene

A novel stress-inducible metallothionein-like gene from rice, designated as rgMT-1 (rice genomic metallothionein-like gene-1), was isolated and sequen ced. From the sequence analysis of its 5'-flanking region, two putative TAT A boxes, one CAAT box, and several short sequences homologous to regulatory cis-elements previously reported were identified. Two direct repeats, one 10 bp in length (CAAATCAAA) and the other 11 bp (GTGAAAATACT), respectively , were also found. By transient GUS (beta-glucuronidase) assay, the express ion of GUS, in vitro, was enhanced by the presence of the rgMT-1 intron. Th e critical region which controls the basal transcription was shown to lie b etween -73 and -36 upstream of rgMT-1, in which one of the two putative TAT A boxes was located. The promoter activity was lost completely when both pu tative TATA boxes were deleted. This is the first report describing the gen omic structure and regulation of a monocotyledonous metallothionein-like ge ne critical to the response of stress.