Gene clone and functional identification of sterol glycosyltransferases from Paris polyphylla var. yunnanensis / 中国中药杂志

In this study, the authors cloned a glycosyltransferase gene PpUGT2 from Paris polyphylla var. yunnanensis with the ORF length of 1 773 bp and encoding 590 amino acids. The phylogenetic tree revealed that PpUGT2 belonged to the UGT80A subfamily and was named as UGT80A49 by the UDP-glycosyltransferase(UGT) Nomenclature Committee. The expression vector pET28a-PpUGT2 was constructed, and enzyme catalytic reaction in vitro was conducted via inducing protein expression and extraction. With UDP-glucose as sugar donor and diosgenin and pennogenin as substrates, the protein was found with the ability to catalyze the C-3 hydroxyl β-glycosylation of diosgenin and pennogenin. To further explore its catalytic characteristic, 15 substrates including steroids and triterpenes were selected and PpUGT2 showed its activity towards the C-17 position of sterol testosterone with UDP-glucose as sugar donor. Homology modelling and molecule docking of PpUGT2 with substrates predicted the key residues interacting with ligands. The re-levant residues of PpUGT2-ligand binding model were scanned to calculate the corresponding mutants, and the optimized mutants were obtained according to the changes in binding affinity of the ligand with protein and the surrounding residues within 5.0 Å of ligands, which had reference value for design of the mutants. This study laid a foundation for further exploring the biosynthetic pathway of polyphyllin as well as the structure of sterol glycosyltransferases.

Cloning and Prokaryotic Expression of Glycosyltransferase Genes from Paris polyphylla var. yunnanensis / 中国实验方剂学杂志

Objective:To clone the full-length glycosyltransferase genes （<italic>PpUGT</italic>1，<italic>PpUGT</italic>7） related to saponins biosynthesis in <italic>Paris polyphylla</italic> var. <italic>yunnanensis</italic>，and perform bioinformatics analysis，relative expression analysis and prokaryotic expression analysis. Method:Total RNA was isolated from <italic>P. polyphylla </italic>var. <italic>yunnanensis </italic>with use of the Eastep^® Super Total RNA Extraction Kit and converted to cDNA. Specific primers were designed according to the transcriptome data to clone the full-length gene. Relevant software was then used for bioinformatic analysis of the protein sequences. The relative gene expression levels were detected by real-time fluorescent quantitative polymerase chain reaction （Real-time PCR） and the prokaryotic expression vectors were built to heterologously express recombinant protein in <italic>Escherichia coli.</italic> Result:The open reading frame （ORF） of <italic>PpUGT</italic>1 was 1 827 bp，encoding 608 amino acids，and was predicted as a steroid glycosyltransferase；the ORF of <italic>PpUGT</italic>7 was 1 380 bp，encoding 459 amino acids，and was predicted as a triterpenoid glycosyltransferase. The calculated relative molecular mass of two proteins were 67.6 kDa and 51.3 kDa respectively，and both of them were hydrophilic proteins，no transmembrane domain，no signal peptides，both showing high similarity and conservativeness with homologous sequences. The results of Real-time PCR showed that the expression level of <italic>PpUGT</italic>1 was root>leaf>flower>stem；the expression level of <italic>PpUGT</italic>7 was stem>leaf>flower>root. In addition，PpUGTs proteins were expressed in <italic>E. coli</italic>. in a soluble form. Conclusion:The genes of <italic>PpUGT</italic>1 and <italic>PpUGT</italic>7 were cloned successfully. Real-time PCR showed the genes were expressed differently in different plant organs， and their recombinant proteins were successfully expressed in <italic>Escherichia coli</italic>. This study lays a foundation for functional characterization of PpUGTs and analysis of the biosynthesis pathway of saponins in <italic>Paris polyphylla </italic>var. <italic>yunnanensis</italic>.

Cloning and characterization of a monoterpene synthase gene from Tripterygium wilfordii / 中国中药杂志

Tripterygium wilfordii is a medicinal plant commonly used in the treatment of rheumatoid arthritis,and with pharmacological activities in anti-tumor and obesity treatment. The known active ingredients in T. wilfordii are mainly terpenoids,but with very low content. Therefore,the analysis of the biosynthesis pathway of terpenoids in T. wilfordii has become a research hotspot to solve the problem of its resources. Terpenoid synthase( TPS) is a key enzyme that catalyzes the formation of a wide variety of terpenoid skeletons. In this study,a gene fragment with an ORF of 1 785 bp was cloned from T. wilfordii. Bioinformatics analysis was performed using NCBI's BLASTP,ProtParam and Interpro online tools and MEGA 6.0 software. The response of this gene to methyl jasmonate was also detected by real-time fluorescent quantitative PCR,and its catalytic function was verified by prokaryotic expression and in vitro enzymatic assay. Bioinformatics analysis indicated that the amino acid sequence encoded by this gene had both N-terminal domain and C-terminal domain of TPS,as well as the DDxx D conserved domain of the class I of TPS family. And Tw MTS gathered together with TPS-b subfamily in the Neighbor-Joining Tree constructed with known homologous TPSs. The results of RT-PCR showed that 50 μmol·L-1 MeJA 12 h could increase the expression of Tw MTS to 735 times in the control group at 12 h,and 1 644 times at 24 h. In addition,in vitro enzymatic reaction results showed that Tw MTS can catalyze the production of β-citronellol with GPP as substrate,indicating that Tw MTS was a monoterpene synthase. The above results provided a new element for the synthetic biology database of T. wilfordii terpenoids,and laid the foundation for future biosynthesis research.

DNA molecular identification of Manis pentadactyla / 中国中药杂志

The study was aimed to establish a stable, accurate site specific PCR identification system to identify Manis pentadactyla and its adulterants using DNA molecular identification. The genomic DNA was extracted from experimental samples using the DNA extraction kit. The Cytb and CO Ⅰ genes were amplified using PCR and sequenced bi-directionally. Obtained sequences were assembled using the BioEdit software. The neighbor-joining tree was constructed by MEGA 6.0. Specific identification primers were designed according to the specific allelets, and PCR reaction system was optimized. The results indicated that the Cytb and CO Ⅰ sequence both were able to be used to identify M. pentadactyla and its adulterants. With the specific primers CO Ⅰ-S10/A5, the M. pentadactyla could be amplified a 400 bp DNA band when the annealing temperature ranged from 55 to 60 ℃ and the amount of DNA template ranged from 3 to 100 ng within 35 PCR cycles. However, other adulterants displayed no relevant bands. So that primers CO Ⅰ- S10 / A5 can be used to identify the M. pentadactyla with the adulterants.

Cloning and protein expression analysis of geranyl diphosphate synthase genes in Tripterygium wilfordii / 中国中药杂志

Based on the transcriptome data, the study cloned full-length cDNA of TwGPPS1 and TwGPPS2 genes from Tripterygium wilfordii suspension cells and then analyzed the bioinformation of the sequence and protein expression. The cloned TwGPPS1 has a 1 278 bp open reading frame (ORF) encoding a polypeptide of 425 amino acids. The deduced isoelectric point (pI) was 6.68, a calculated molecular weight was about 47.189 kDa. The full-length cDNA of the TwGPPS2 contains a 1 269 bp open reading frame (ORF) encoding a polypeptide of 422 amino acids. The deduced isoelectric point (pI) was 6.71, a calculated molecular weight was about 46.774 kDa.The entire reading frame of TwGPPS1,2 was cloned into the pET-32a(+) vector and expressed in E. coli BL21 (DE3) cells to obtain the TwGPPS protein, which laid a basis for further study on the regulation of terpenoid secondary metabolism and biological synthesis.

Cloning and protein expression of sterol-C-24-methyl transferase 2 in Tripterygium wilfordii / 药学学报

24-Alkyl sterols are the major players in the control of membrane component and plant growth. In this paper, we cloned an important rate-limiting enzyme:sterol-C-24-methyl transferase (SMT) in the sterol biosynthetic pathway according to the transcriptome data of Tripterygium wilfordii. suspension cells, whose full-length cDNA was 1 631 bp with an open reading frame of 1 080 bp, encoding a protein of 359 amino acids. It was estimated that theoretical isoelectric point (pI) was 6.43 and the molecular mass was 40.0 kDa. Bioinformatics analysis attributed the SMT gene to SMT2 family. The expression vector was constructed as the pMAL-c2x-TwSMT2 plasmid and the recombinant protein was expressed in E. coil BL21 (DE3) competent cells. After methyl jasmonate treatment, the relative expression level of TwSMT2 has improved significantly in 24 h. SDS-PAGE electrophoresis and Western Blot showed that protein of TwSMT2 in BL21 (DE3) strain was expressed after induction by IPTG. In this study, TwSMT2 was cloned for the first time and the recombinant protein was expressed, which lay the foundation for elucidation of the sterol biosynthetic pathway of Tripterygium wilfordii in the future.

Effects on Salvia miltiorrhiza hairy roots of tanshinones content accumulation after treated with fosmidomycin / 中国中药杂志

Fosmidomycin (100 micromol x L(-1)) which is the effective inhibitor of DXR, key enzyme in terpenoid MEP pathway, was used to treat with hairy roots of Salvia miltiorrhiza. The treated roots were harvested at 2, 4, 6, 8, 10, 16 and 21 d, mRNA level of SmDXR and tanshinone content in treated and negative control groups were detected. Results found that, after treated with fosmidomycin, color of S. miltiorrhiza hairy roots grew pale gradually comparing with controls; mRNA level of SmDXR in hairy roots varied as a shape of parabolic and the highest value achieved at the sixth day after treatment, then it decreased gradually; Content of four kinds of tanshinones were detected. Among of the four kinds of tanshinones, Tanshinone I content changed relatively little, while content of dihydrotanshinone I, cryptotanshinone and tanshinone II (A) decreased gradually in 21 days. The content of total tanshinones in NC groups was 5, 63 times more than FOS-treated roots in the 21th day. The previous results showed that SmDXR played an important role in the accumulation of tanshinone content in MEP pathway. Once the mRNA level of SmDXR was suppressed, the accumulation of secondary metabolites will be significantly affected.

Advances in studies on 3-hydroxy-3-metllylglutaryl coenzyme A reductase in terpenoids biosynthesis of medicinal plants / 中国中药杂志

There exists many kinds and a huge number of terpenoid in medicinal plants, which show a wide range of pharmacological activities. 3-Hydroxy-3-metllylglutaryl coenzyme A reductase(HMGR) is a key rate-limiting enzyme in terpenoid biosynthetic pathway . HMGR plays an important role in the regulation of secondary metabolism of the terpenoid. The paper summarized the biological function and the catalytic mechanism of HMGR, the cloning and the structure of the gene as well as its research progress in some medicinal plants.

Establishment and analysis of in vitro culture system for transgenic Salvia miltiorrhiza hairy roots / 中国中药杂志

<p><b>OBJECTIVE</b>To establish a culture system for transgenic Salvia miltiorrhiza hairy roots.</p><p><b>METHOD</b>Investigated the success rate of different explants, different infection time and different co-culture time to induce hairy roots of S. miltiorrhiza. Co-cultured explants were sterilizated with 400 g x L(-1) Cef water for 5 min, inoculated on MS solid medium supplied with 400 mg x mL(-1) cef and 2.5 g x L(-1) Hyg, and then transfered to the 67-V liquid medium with 2.5 g x L(-1) Hyg after complete sterilization. GFP fluorescence detection was performed to detect positive hairy root lines. PCR method to detect rolC gene which is the specific gene of hairy root. Biomass was determinated in different growth periods of root lines. HPLC was conducted to measure the content of dihydrotanshinone I of transgenic hairy roots.</p><p><b>RESULT</b>Leaf base of S. miltiorrhiza was used as a perfect explant to Induce hairy roots, the success rate can reach 93.3%. Inducing efficiency was up to 63.3% after Agrobacterium infection for 10 min. Co-culture for 2-3 d can reach the best induced effect. It is a high credibiliy to use PCR method combined with detection of GFP fluorescence to identified positive transformants. There is a close contact between biomass increases and secondary metabolite accumulation of transgenic hairy roots.</p><p><b>CONCLUSION</b>Successfully in vitro culture system has been established in transgenic S. miltiorrhiza, and this research can lay foundations for the further genetic engineering applications.</p>

Cloning and expression analysis of a new 3-hydroxy-3-methylglutaryl coenzyme A reductase gene from Salvia miltiorrhiza (SmHMGR3) / 中国中药杂志

<p><b>OBJECTIVE</b>To clone and analysis a new 3-hydroxy-3methylglutary CoA reductase cDNA from Salvia miltiorrhiza (SmHMGR3).</p><p><b>METHOD</b>Transcription database of S. miltiorrhiza was used and a new regulatory gene from terpene secondary metabolic pathway has been cloned. ORF Finder was used to find the open reading frame of SmHMGR3 cDNA and ClustalW has been performed to analysis the multiple amino acid sequence alignment. Phylogenetic tree has been constructed using MEGA5.0. RT-PCR has been applied to detect the transcription level of SmHMGR3 in roots, stems and leaves from flowering S. miltiorrhiza plant. The mRNA level of SmHMGR3 gene from hairy roots was detected after elicitor Ag+ supplied.</p><p><b>RESULT</b>The SmHMGR3 cDNA sequence was obtained. The total length of SmHMGR3 cDNA was 1,692 bp encoding 563 amino acids. The homology rate was 75.04% and 80.64% comparing with SmHMGR1 and SmHMGR2 respectively. QRT-PCR results showed that the highest mRNA level existed in leaves of S. miltiorrhiza. After induced by Ag for 24h, the transcription level reached the highest value.</p><p><b>CONCLUSION</b>A new SmHMGR3 gene has been obtained for the first time, and which can provide the new target for the further studies about tepenes metabolism.</p>