PROMOTER SEQUENCES FROM 2 DIFFERENT BRASSICA-NAPUS TAPETAL OLEOSIN-LIKE GENES DIRECT TAPETAL EXPRESSION OF BETA-GLUCURONIDASE IN TRANSGENICBRASSICA PLANTS

To investigate the sequences responsible for the regulated expression of tapetal-specific oleosin-like genes, ca. 2 kb of the 5'-upstream re gions from two divergent genes, OlnB;4 and OlnB:13, were isolated, seq uenced and fused to the reporter gene beta-glucuronidase for study in transgenic Brassica napus plants. Although the proteins encoded by the se two genes are highly divergent, except for the conserved oleosin-li ke domain, the first 250 bp of their 5'-upstream regions was 86% ident ical, including a region of 150 bp upstream from the TATA box. Analysi s of 42 independent transformants by histochemical and fluorometric me thods showed that both promoters directed tapetal-specific expression that peaked at the 4 mm flower bud stage.