CDNA Cloning Of Squalene Synthase From Astragalus Membranaceus (fish.) Bunge

Astragalus membranaceus (Fish.) Bunge is the Leguminosae Astragalus plants. Chinese medicine membranaceus is refers to the Astragalus membranaceus (Fish.)Bunge or Astragalus membranaceus (Fish.) Bge. var. mongholicus (Bge.) Hsiao'dry roots ,it is a famous popular tonic medicine. According to Pharmacopoeia records, Astragalus has qi Sun,solid form antiperspirant, virus-free tissue regeneration benefits of water off the swellingand other effects, indications Qi weakness, weak digestion, spontaneous sweating,night sweats, hypertension, diabetes, edema, and sore eventually becoming heal sickness .The medicinal part of Astragalus roots contains saponins, polysaccharides, flavonoids, trace elements and amino acids and other active ingredients, including astragalus Astragalus saponin is the main one of the main active ingredient, with blood pressure, anti-inflammatory, analgesic and metabolic regulation and so on.Study at home and abroad for the astragalus, astragalus in recent years mainly in the chemical composition of the extraction and identification, and various aspects of the pharmacological effects of chemical composition, and biosynthesis of Astragalus medicinal ingredients of research has not been reported but its application basic research is still very weak, especially in the medicinal ingredients of Astragalus saponins biosynthesis pathway related genes. Therefore squalene synthase gene Astragalus Astragalus and squalene synthase genes have a certain value. Squalene synthase (squalene synthase), also known as squalene synthase, squalene able to catalyze the synthesis of the biological activity of squalene strong, is widely used in health care products and cosmetics, etc., and its downstream steroid product class and saponins have important physiological functions, the activity of squalene synthase in the isoprenoid pathway in other branches, but also to its competitive semi-terpene, diterpene and other substances, so co-squalene enzyme to become a research hotspot.According to other species' squalene synthase protein highly conserved sequence, and with reference to the gene sequence we sign a pair of middle primers and more on both ends of the primers to determine the appropriate detection of a pair of primers though multiple PCR, from the capsule Astragalus we Cloned cDNA sequences of squalene synthase gene (GenBank accession number HQ829974). Using software DNAMEN deduced astragalus squalene synthase protein ,it is sequence hinhest sinilarity to soybean(BAA22559.1),reaching 88%.Doing semi-quantitative PCR on squalene synthase gene mRNA of root leaves and stem ,the reasults showed that squalene synthase in the stems root and leaf expression is reduced in turn.For this experiment ,the hydrophobic squalene synthase gene fragment designed primers,PCR amplified fragments into the expression vextor pET-32a(+) Vectors, use the expression strain Rosetta was induced by IPTG, we success express protein. Cloning of astragalus squalene synthase gene can help improving astragaloside content and though binlogical engineering produce astragaloside.