Promoter activity of the 5' flanking region of a tobacco glycolate oxidase gene in transgenic tobacco plants.

A clone harboring the 5' flanking region of a tobacco glycolate oxidase (GLO) gene was isolated from a lambda EMBL3-tobacco genomic DNA library. Primer extension analysis indicated two major transcripts with 76 and 81 bp 5' UTRs. An RT-PCR assay mapped the major mRNA transcription initiation site to thymine at position 81 upstream of the translation initiation codon. A putative TATA box spanning positions -56 to -50 upstream of the transcription initiation site was found. Promoter activity of the 5' flanking region (-3.0 kb to +82 bp) was demonstrated in tobacco plants transformed with a GLO-beta-glucuronidase (GUS) chimeric gene. Furthermore, in these transgenic plants, GUS expression patterns mimicked the expression patterns of the endogenous GLO.