Research paperIsolation and sequence analysis of napin seed specific promoter from Iranian Rapeseed (Brassica napus L.)

- We isolated Napin promoter from an Iranian variety of B. napus for the first time.
- We found some motifs that they had key roles in seed-specific activity.
- Isolated promoter had differences with other napin promoters in B. napus.
- The promoter had differences with napin promoter of B. juncea, oleracea and rapa.

Rapeseed (Brassica napus L.) has become an important crop during the last 30 years. In addition to a high lipid level, the seeds also have a significant protein content, which constitutes 20-25% of the dry seed weight. The synthesis of storage proteins is primarily controlled at transcriptional level and seed-specific expression has been shown to be conferred upon the promoter regions of many storage protein genes. Napin is one of the main storage proteins in rapeseed's embryo that is produced in seed developing stage. Its promoter region located at 5′ upstream of the napin gene has already been isolated (GenBank number, EU416279.1). In current research, seed-specific promoter (napin) of Iranian B. napus L. was isolated from the genomic DNA and cloned into pBI121 plant binary vector to use in future researches. For this purpose, the napin promoter was amplified by PCR method using specific primers, cloned in pSK+ vector and sequenced. Sequencing analysis showed that the cloned promoter contained all of conserved motifs such as TATA box (TATAAA), RY repeats (CATGCA), dist-B (TCAAACACC) and prox-B elements (GCCACTTGTC), G-box (CACGTG) and CAAT Motifs, which constituted the seed-specific promoter activity and according to this analysis, the seed-specific promoter activity of cloned sequence was predicted. Based on sequence distances of nucleotide sequences, our sequence had the highest similarity (99.8%) whit B. napus sequence (with EU416279.1 accession number). Finally the promoter obtained might be interesting not only as a useful tool for biotechnological application but also for fundamental research.