转甲状腺素蛋白基因在酵母中的表达及产物的功能研究

Transthyretin(TTR) is possibly involved in the transport of thyroxine and Vitamin A. Since 1991, it was first reported by Shanghai Cancer Institute that TTR gene could be the candidate of the anti-oncogene related to human hepatoma, which means that TTR could be useful in future clinical therpy. The current project is proposed to study the expression of TTR gene in yeast and search for new approaches to mass production of TTR by genetic engineering. The majority of our proposed targets have been achieved. The engineered yeast strains of Pichia pastoris have been successfully constructed, and proved to express rTTR at high levels (100mg/L). The flask fermentation techniques and methods for rTTR purification have also been established. Several bathes of purified rTTR have been obtained with more than 95% purity. The results obtained through experiments such as SDS-PAGE, western blotting and Mr and PI determination indicated that purified rTTR protein expressed by Pichia pastoris have very similar characteristics to the natural TTR protein purified from human serum. The work we carried out provided a basis for the production of TTR by genetic engineering and could promote the study on the biological effect of TTR. However, the vitro test did not show an evident inhibition of the growth of hepatoma cells either by rTTR obtained from our experiments or by standard TTR. The reason remains to be found out.

将转甲状腺素蛋白（TTR）基因的部分氨基酸密码子改为酵母偏爱密码子，并使该基因多拷创显诒铣嗍辖湍傅娜旧迳希ü骺谹OX1启动子使宿主菌高水平转录TTR基因，从而了解TTR基因在毕赤氏酵母中的表达规律。为基因工程生产TTR积累经验，为肝癌治疗的临床实验创造条件。本相研究设计肿瘤分子生物学和基因工程学的学科交叉，有医学应用价值。