MFα Signal Peptide Enhances the Expression of Cellulase eg1 Gene in Yeast
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Ethanol production from lignocellulose by recombinant yeast with high level expression of heterologous cellulase genes has been a major anticipation. The native secretion signal sequence of the cellulase endoglucanase I (eg1) gene was replaced by Saccharomyces cerevisiae mating factor α prepro-leader sequence (MFα). The transformants containing native secretion signal (Y 1) and MFα secretion signal (Y 2) were characterized with respect to gene expression and growth on cellulose substrate. Increased enzyme activity and cellulose utilization were observed. The enzyme activity of Y 2 was 0.084 U/ml, 61.5% higher than Y 1 (0.052 U/ml). The sufficiency parameter (S value) was raised from 0.6 to 0.84. MFα signal peptide was more efficient than the native signal peptide of eg1 gene, suggesting that signal peptide replacement is an efficient way to enhance the cellulase expression level in yeast, for cellulose-derived ethanol production.
KeywordsGene expression Signal peptide Endoglucanase I Yeast
This work was supported by the National Natural Science Foundation of China (No. 50673078), the “863” Project of the Ministry of Science and Technology (No. 2007AA022004), the Innovation Program of Shanghai Municipal Education Commission (No. 08ZZ21), and the Yong faculty grant of Anhui Agricultural university (No. yj2008-25).
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