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. 2015 May 17;13(5):338–345. doi: 10.1016/S1875-5364(15)30024-8

Enhancing ergosterol production in Pichia pastoris GS115 by overexpressing squalene synthase gene from Glycyrrhiza uralensis

Ying LIU a, Xiao-Qing ZHU a, Wen-Dong LI b, Hao WEN a, Chun-Sheng LIU a,*
PMCID: PMC7128851  PMID: 25986282

Abstract

The present study was designed to determine the effects of copy number variations (CNVs) of squalene synthase 1(SQS1) gene on the mevalonate (MVA) pathway. SQS1 gene from G. uralensis (GuSQS1) was cloned and over-expressed in Pichia pastoris GS115. Six recombinant P. pastoris strains containing different copy number of GuSQS1 were constructed. HPLC was used to assay the level of ergosterol in all transgenic P. pastoris strains containing GuSQS1. HPLC analysis showed that the contents of ergosterol in all of the transgenic P. pastoris containing GuSQS1 were higher than that in the negative control. And with the increase of copy number of GuSQS1, the content of ergosterol showed an increasing-decreasing-increasing pattern. The contents of ergosterol in 10-copy-GuSQS1 P. pastoris and 47-copy-GuSQS1 P. pastoris were significantly higher than that in the rest recombinant P. pastoris strains. In conclusion, the CNVs of GuSQS1 influence the content of secondary metabolites in the MVA pathway. The present study provides a basis for over-expressing GuSQS1 and increasing the content of glycyrrhizin in G. uralensis cultivars.

Key Words: Glycyrrhiza uralensis, GuSQS1, Over-expression, Pichia pastoris, Copy number variations

Six recombinant P. pastoris strains containing different copy number of GuSQS1 gene were obtained in this paper. HPLC analysis showed that the content of ergosterol in all recombinant P. pastoris containing GuSQS1 gene were higher than that in negative control. And with the increase of copy number of GuSQS1 gene, the content of ergosterol was presented in an increasing-decreasing-increasing pattern.

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Footnotes

Available online 20 May 2015

Research funding This work was supported by National Natural Science Fundation of China (No. 81373909).

These authors have no conflict of interest to declare.

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