Abstract
In a variety of organisms including Arabidopsis, it is known that highly expressed genes preferentially use one of synonymous codons. This phenomenon is interpreted as a evolutional result to facilitate the efficiency of translation of highly required genes which mRNAs are estimated to be abundant. However we hypothesized the opposite possibility that efficient translation dependent on the optimized codons stabilized mRNA.
To analyze the effect of codon choice on the gene expression, we compared the synthesized luciferase gene which contained only one of synonymous codons preferentially used in highly expressed gene, named opLuc, to generally used luciferase, referred as 40Luc in this study. Both genes were introduced into Arabidopsis cultured cell line T87 by Agrobacterium. The transformats having opLuc gene expressed higher level of mRNA, protein and activity for luciferase than those having 40Luc. This higher expression was independent of the copy number of the introduced gene and both opLuc and 40Luc was transcribed at almost same rate. These results suggested that codons used in opLuc stabilized mRNA and increased the gene expression.
