摘要
叶绿体中的psbA是一个编码QB蛋白的光调节基因。我们用带有豌豆psbA基因和lacZ基因融合体的质粒,研究了无光诱导下在E.coli中的表达。结果表明:含有psbA及其上游166碱基的DNA片段能在黑暗中表达。同时还表明,在植物中,psbA基因启动子是潜在的有较高活性的启动子,在黑暗中不能表达可能是由于受到特定的调节机制制约。叶绿体的psbA基因与E.coli的基因上游“pribnow”盒与“-35”盒有较高的同源性。这为叶绿体与光合原核生物有共同的起源提供了证据。
The expression of light-regulated psbA gene in prokaryote-E, coli. was investigated. A DNA sequence for β-galactosidase coding region was fused to a uncompleted psbA gene from P. sativum as a gene reporter. The results of assaying β-galactosidase activity showed that the psbA gene with 166 bp up stream from open reading frame could constitutively express in darkgrown E. coli. The β-galactosidase activity. driven by psbA promoter is 3-fold higher than that done by kanamycin promoter. These mean the light-regulation mechanisms do not deal with the DNA sequences themselves of both 166 up stream including promoter region and coding region. The strong expression of psbA gene in E. coli indicates the promoter is a potential strong one in dark-grown higher plants but needs some specific conditions for its expression. DNA sequences 10 and 35 bp up stream from psbA transcript showed homology to-10 and-35 consensus promoter sequences in E. coli. This fact as well as the strong expression of chloroplast psbA gene in E. coli provide new evidence for the view that chloroplast and some photosynthetic prokaryote have the common ancestry.
出处
《实验生物学报》
CSCD
1990年第4期399-404,共6页
Acta Biologiae Experimentalis Sinica
