Different sets of cis-elements contribute to the expression of a catalase gene from castor bean during seed formation and postembryonic development in transgenic tobacco.

Deletion analysis of the promoter region of a gene for catalase, cat2, from castor bean (Ricinus communis) was performed to identify the cis-regulatory elements responsible for the expression of a beta-glucuronidase (GUS) fusion gene during seed formation and postembryonic development in transgenic tobacco. The analysis showed that multiple cis-elements contribute to the activity of the cat2 promoter during seed formation and postembryonic development. The 5'-upstream regions from -1,241 to -816 bp, from -720 to -682 bp, and from -632 to -535 bp, relative to the site of initiation of translation of cat2, contributed positively to the activity of the cat2 promoter during both stages. By contrast, the region from -816 to -720 bp had a negative effect at both stages. The region from -682 to -632 bp contributed positively to the activity during seed formation but negatively during postembyonic development. Histochemical analysis revealed that the multiple cis-elements determined not only the level of expression of the chimeric gene but also the tissue-specificity of such expression. For example, the region from -1,241 to -816 bp allowed expression of the chimeric gene in the axis of the embryo of the dry seed, as well as in the cortex of the middle part of the hypocotyl and at the base of epicotyl in the young seedling.