目的 对参与桑黄三萜合成途径的关键酶鲨烯环氧酶(squalene epoxidase,SE)进行基因全长克隆和生物信息学分析。方法 以桑黄总RNA为模板,采用RT-PCR和RACE技术克隆桑黄SE基因的全长cDNA和DNA序列,并通过ExPASy在线分析等方法对其进行生物信息学分析。结果 序列分析表明,SE基因全长2145 bp,包含6个外显子和5个内含子;所克隆的cDNA全长为1856 bp,包含1个1452 bp的开放阅读框,编码483个氨基酸的蛋白,命名为IbSE1,预测该蛋白的相对分子质量为5.3×10⁴,等电点(pI)为8.41,无信号肽。结论 首次克隆并获得桑黄鲨烯环氧酶基因全长序列,为进一步阐明桑黄三萜代谢途径和改善中药材品质奠定基础。

Objective To clone the full-length cDNA encoding squalene epoxidase (SE), which is the key enzyme involved in the triterpenoid biosynthesis pathway in Inonotus baumii, and analyze its bioinformates. Methods Taking total RNA as template, the full length cDNA and DNA of SE in I. baumii was cloned through RT-PCR and the rapid amplification of cDNA ends (RACE) technique. The bioinformatics of SE gene were analyzed by ExPASy on line. Results Sequence analysis showed that it consisted of 2145 bp with an open reading frame (ORF) of 1 452 bp, encoding 483 amino acid polypeptides. SE gene contained six exons and five introns. The relative molecular mass of SE calculated was 5.3×10⁴, the isoelectric point (pI) was 8.41, and there was no signal peptide in SE. Conclusion It is the first report that the cDNA encoding SE from I. baumii is cloned. This work provides a scientific basis for exploring the triterpenoid biosynthesis pathway of the medicinal ingredient and improving its quality in I. baumii.

博士研究生自主创新基金项目(2572015AA07)