Plant Protein Improvement by Synthetic Gene

합성유전자를 이용한 식물단백질의 향상

To improve the nutritional quality of plant proteins, a synthetic gene, called HEAAE (high essential amino acid encoding)-DNA, was introduced and expressed in tobacco plants. The synthetic gene, which is 292 basepair-long, codes for a protein composed of about 80% essential amino acids. To improve its expression level in plants, Cauliflower Mosaic Virus (CaMV) 355 and CaMV duplicate 35S promoters which are known as strong promoters were used with Nopaline Synthase promoter as a control. Transformed and regenerated tobacco plants were subject to analysis for introduction and expression of this gene. Integration of the gene into the plant genome and its expression into mRNAs and its proteins have been demonstrated using Southern, northern blot analysis and amino acid analysis. The differences of expression levels among CaMV duplicate 35S, CaMV 35S and Nopaline Synthase promoters are significant in term of mRNAs, but not in terms of proteins.

식량으로 쓰이는 식물 단백질은 공통적으로 Isoleucine, Lysine, Methionine, Threonine, Tryptoplan등 5가지 필수아미노산이 결핍되어있다. 본 연구에서는 이러한 필수아미노산을 다량 함유한 단백질을 발현시킬 수 있는 합성유전자를 fekaqo에서 높은 수준으로 발현시키고자 강한 식물 promoter로 알려진 CaMV 35S, CaMV duplicate 35S promoters를 사용하였다. 형질 전환 및 재분화된 식물을 분석한 결과 본 합성 유전자가 식물 nuclear genome 안으로 도입을 안정하여 잘되었고 mRNA수준까지는 유의적인 증가를 보였으나 단백질 수준에서는 유의적 수준의 증가를 관찰할 수 없었다.