اثر Codon Usageبر بيان ژن فاكتور رشد بازي فيبروبلاست (hbFGF) در Escherichia coli

Effect of codon usage on the expression of human basic fibroblast growth factor gene in Escherichia coli

However, the 61 amino acids genetic code has been found to be almost universal, each organism carries its own bias in the usage of available amino acid codons. This will cause problem in the expression of the recombinant proteins in heterologous hosts. Because most amino acids are encoded by more than one codon, we can change codons according to their usage in a special host such as E. coli, without changing in amino acids sequence. Silent mutation in hbfgf cDNA was carried out by Site Directed Mutagenesis method. The expression level was measured by SDS-PAGE technique and compared to the level of expression in the native gene. Expression level in mutant and native genes indicated a very serious difference. In contrast with the remarkable bands of native gene there were no significant mutant gene bands in SDS-PAGE analysis. Because of the same conditions of mutant and native genes up to the transcription, this serious difference might relate to the mRNA efficiency for translation. Our results indicate that increased stability of 5ʹ mRNA secondary structures in the E. coli prevents efficient translation initiation.