Codon Optimization Increases Steady-State mRNA Levels in Aspergillus oryzae Heterologous Gene Expression

摘要: We investigated the effect of codon optimization on expression levels heterologous proteins in Aspergillus oryzae, using mite allergen Der f 7 as a model protein. A codon-optimized gene was synthesized according to frequency usage A. oryzae by recursive PCR. Both native and optimized genes were expressed under control high-level-expression promoter with their own signal peptides or fusion construct glucoamylase (GlaA). Codon markedly increased protein mRNA production both nonfused GlaA-fused constructs. For constructs codons, analysis 3' rapid amplification cDNA ends revealed that poly(A) tracts tended be added within coding region, producing aberrant mRNAs lack termination codon. Insertion between carrier GlaA resulted increases secreted-carrier-GlaA levels. These results suggested without result premature polyadenylation are degraded, possibly through nonstop decay pathway. suggest elimination cryptic signals 7, thereby circumventing truncated transcripts resulting an increase steady-state