ASPARTIC PROTEINASE GENES IN THE BRASSICACEAE ARABIDOPSIS-THALIANA AND BRASSICA-NAPUS

Active aspartic proteinase is isolated from Brassica napus seeds and t he peptide sequence is used to generate primers for PCR. We present he re cDNA and genomic clones for aspartic proteinases from the closely r elated Brassicaceae Arabidopsis thaliana and Brassica napus. The Arabi dopsis cDNA represents a single gene, while Brassica has at least 4 ge nes. Like other plant aspartic proteases, the two Brassicaceae enzymes contain an extra protein domain of about 100 amino acids relative to the mammalian forms. The intron/exon arrangement in the Brassica genom ic clone is significantly different from that in mammalian genes. As t he proteinase is isolated from seeds, the same tissue where 2S albumin s are processed, this implies expression of one of the aspartic protei nase genes there.