Seed-specific regulation of the napin promoter in Brassica napus.

摘要

The expression of the 2S storage protein napin in Brassica napus (rape) is dependent upon ABI3. Mutation analyses identified a promoter segment between -152 to -120, denoted the B-box, to be critical for the activity of the promoter in transgenic tobacco (Nicotiana tabacum) seeds. The B-box, which is highly conserved in all 2S promoters and which displays similarity to abscisic acid response elements, binds at least two different nuclear protein complexes. Mutation of either of the two B-box elements binding nuclear protein complexes abolished the activity of the promoter in transgenic tobacco seeds. The concatemerised B-box in front of the minimal 35S promoter from cauliflower mosaic caulimovirus directed seed-specific transcription in transgenictobacco and was able to induce transcription in young tobacco seedlings ectopically expressing ABI3. It is concluded that the B-box is one region through which ABI3 controls the napin promoter.