Cloning, expression analysis and enzyme activity verification of dihydroflavonol 4-reductase from Cistanche tubulosa (Schenk) Wight flower / 药学学报

Dihydroflavonol 4-reductase (DFR) plays an essential role in the biosynthesis of anthocyanin and regulation of plant flower color. Based on the transcriptome data of Cistanche tubulosa (Schenk) Wight, a full-length cDNA sequence of CtDFR gene was cloned by reverse transcription-polymerase chain reaction (RT-PCR). CtDFR contains an open reading frame (ORF) of 1 263 bp which encodes 420 amino acids with a predicted molecular weight of 47.5 kDa. The sequence analysis showed that CtDFR contains a nicotinamide adenine dinucleotide phosphate (NADPH) binding domain and a specific substrate binding domain. The expression analysis indicated that CtDFR was highly expressed in red and purple flowers, and the relative expression levels were 4.04 and 19.37 times higher than those of white flowers, respectively. The recombinant CtDFR protein was expressed in E.coli BL21 (DE3) using vector pET-28a-CtDFR and was purified. In vitro enzyme activity analysis, CtDFR could reduce three types of dihydroflavonols including dihydrokaempferol, dihydroquercetin, and dihydromyricetin to leucopelargonidin, leucocyanidin and leucodelphinidin. Subcellular localization analysis showed that CtDFR was mainly localized in the cytoplasm. These results demonstrate that CtDFR plays an important role in regulation of flower color in C. tubulosa and make a valuable contribution for the further investigation on the regulation mechanism of C. tubulosa (Schenk) Wight flower color.

Prokaryotic expression, subcellular localization and enzymatic activity analysis of DXS gene from Platycodon grandiflorum / 药学学报

1-Deoxy-D-xylulose-5-phosphate synthase (DXS), the first key enzyme in 2-methyl-D-erythritol-4-phosphate (MEP) pathway, catalyzes the condensation of glyceraldehyde-3-phosphate with pyruvate to 1-deoxy-xylose-5-phosphate (DXP). In this study, PgDXS1, PgDXS2, and PgDXS3 genes were cloned from the root of Platycodon grandiflorum (P. grandiflorum). The open reading frame (ORF) of PgDXS1, PgDXS2, and PgDXS3 were 2 160, 2 208, and 2 151 bp in full length, encoding 719, 735, and 716 amino acids, respectively. Homologous alignment results showed a high identity of PgDXSs with DXS in Hevea brasiliensis, Datura stramonium and Stevia rebaudiana. The recombinant expression plasmids of pET-28a-PgDXSs were constructed and transformed into Escherichia coli (E. coli) BL21 (DE3) cells, and the induced proteins were successfully expressed. Subcellular localization results showed that PgDXS1 and PgDXS2 were mainly located in chloroplasts, and PgDXS3 was located in chloroplasts, nucleus and cytoplasm. The expression of three DXS genes in different tissues of two producing areas of P. grandiflorum were assayed via real-time fluorescence quantitative PCR, and the results showed that all of them were highly expressed in leaves of P. grandiflorum from Taihe. Under methyl jasmonate (MeJA) treatment, the expression levels of three PgDXS genes showed a trend of first decreasing and then increasing at different time points (3 - 48 h), and the activity of DXS showed a trend of first increasing and then decreasing in three tissues of P. grandiflorum. This study provides a reference for further elucidating the biological function of PgDXS in terpenoid synthesis pathway in P. grandiflorum.

Identification and expression analysis of NHX gene family in Chinese cabbage / 生物工程学报

Na+/H+ antiporter (NHX) gene subfamily plays an important role in plant response to salt stress. In this study, we identified the NHX gene family members of Chinese cabbage and analyzed the expression patterns of BrNHXs gene in response to abiotic stresses such as high temperature, low temperature, drought and salt stress. The results showed that there were 9 members of the NHX gene family in Chinese cabbage, which were distributed on 6 chromosomes respectively. The number of amino acids was 513-1 154 aa, the relative molecular weight was 56 804.22-127 856.66 kDa, the isoelectric point was 5.35-7.68. Members of BrNHX gene family mainly existed in vacuoles, the gene structure is complete, and the number of exons is 11-22. The secondary structures of the proteins encoded by the NHX gene family in Chinese cabbage had alpha helix, beta turn and random coil, and the alpha helix occurred more frequently. Quantitative real-time PCR (qRT-PCR) analysis showed that the gene family members had different responses to high temperature, low temperature, drought and salt stress, and their expression levels differed significantly in different time periods. BrNHX02 and BrNHX09 had the most significant responses to these four stresses, and their expression levels were significantly up-regulated at 72 h after treatments, which could be used as candidate genes to further verify their functions.

Subcellular localization of macrophage migration inhibitory factor and its diverse biological functions in tumors / 药学学报

Macrophage migration inhibitory factor (MIF) is an enzyme-active pleiotropic cytokine that is expressed in various immune cells and tumor cells. MIF plays diverse roles in inflammation and tumor progression. It acts as a cytokine involved in immune response and inflammatory lesions. Additionally, MIF is closely associated with tumor proliferation, metastasis, and other tumor hallmarks, exerting a multifaceted influence on tumor occurrence and progression. MIF not only functions by being secreted into the extracellular space as a cytokine but can also be localized within the cytoplasm and nucleus, exhibiting diverse biological functions. As MIF in promoting tumor progression becomes increasingly recognized, MIF-based therapeutic strategies have become a hot research topic in oncology. Here, we provide a comprehensive review of MIF with different subcellular localization about their pro-tumoral functions. A better understanding of MIF in tumor biology will bring broader perspectives for the development of novel MIF targeting strategies and give promising direction for future tumor treatments.

Physicochemical properties, molecular structure, antioxidant activity, and biological function of extracellular melanin from Ascosphaera apis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Ascosphaera apis spores containing a dark-colored pigment infect honeybee larvae, resulting in a large-scale collapse of the bee colony due to chalkbrood disease. However, little is known about the pigment or whether it plays a role in bee infection caused by A. apis. In this study, the pigment was isolated by alkali extraction, acid hydrolysis, and repeated precipitation. Ultraviolet (UV) analysis revealed that the pigment had a color value of 273, a maximum absorption peak at 195 nm, and a high alkaline solubility (7.67%) and acid precipitability. Further chemical structure analysis of the pigment, including elemental composition, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, mass spectrometry, and nuclear magnetic resonance (NMR), proved that it was a eumelanin with a typical indole structure. The molecular formula of melanin is C10H6O4N2, and its molecular weight is 409 Da. Melanin has hydroxyl, carboxyl, amino, and phenolic groups that can potentially chelate to metal ions. Antioxidant function analyses showed that A. apis melanin had a high scavenging activity against superoxide, hydroxyl, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and a high reducing ability to Fe3+. Indirect immunofluorescence assay (IFA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses showed that A. apis melanin was located on the spore wall. The spore wall localization, antioxidant activity, and metal ion chelating properties of fungal melanin have been suggested to contribute to spore pathogenicity. However, further infection experiments showed that melanin-deficient spores did not reduce the mortality of bee larvae, indicating that melanin does not increase the virulence of A. apis spores. This study is the first report on melanin produced by A. apis, providing an important background reference for further study on its role in A. apis.

Cloning and prokaryotic expression analysis of AlCMK from Atractylodes lancea / 药学学报

4-(Cytidine 5′-diphospho)-2-C-methyl-D-erythritol kinase (CMK) was one of the key enzymes in the methylerythritol-4-phosphate (MEP) pathway to generate terpenoids. In this study, based on the transcriptome data of Atractylodes lancea, the sequence of the CMK gene was cloned, named AlCMK (GenBank accession number OM283293). The results showed that AlCMK contains a 1 230 bp open reading frame (ORF) encoding 409 amino acids. The deduced protein had a theoretical molecular weight of 44 752.53 and an isoelectric point of 6.67. Transmembrane structure analysis showed that there was no transmembrane structure, and the secondary structure of AlCMK was predicted to be mainly composed of random coil. Homologous alignment revealed that AlCMK shared high sequence identity with the CMK proteins of Tanacetum cinerariifolium, Osmanthus fragrans, Eucommia ulmoides, Lonicera japonica and Salvia miltiorrhiza. Phylogenetic analysis indicated that AlCMK protein had the higher homology with CMK protein of Compositae. The pET-32a-AlCMK prokaryotic expression vector was constructed and a fusion protein with molecular mass of about 65 kDa was expressed in the E. coli BL21 (DE3). The qRT-PCR was used to analyze the expression pattern of AlCMK gene in different tissues and after MeJA treatment. Meanwhile, the enzyme activity was determined by ELISA kit. The results showed that AlCMK gene was tissue-expressed in different origins and its expression was induced by MeJA, and the results of the enzyme activity assay showed that the AlCMK enzyme activity in different regions was higher in the leaves. The subcellular localization showed that AlCMK was located in the chloroplast. This study provides a reference for further elucidating the biological function of AlCMK gene in terpenoid synthesis pathway in Atractylodes lancea.

Cloning and analysis of STR gene and its promoter from Uncaria / 药学学报

On the basis of the Uncaria transcriptome, specific primers were designed for UrSTR. The full-length cDNA of UrSTR (GeneBank: OL310251) was 1 541 bp, encoding 345 amino acid residues, and the promoter region sequence of UrSTR (GeneBank: OL310252) was 1 179 bp. Phylogenetic tree is revealed that UrSTR had a closest relationship with STR from Ophiorrhiza pumila and Ophiorrhiza japonica. Localization of UrSTR protein is revealed located in the vacuole membrane. Plant-care analysis indicated that the promoter region sequence of UrSTR, covering multiple light, stress and hormone-response cis-regulatory elements, and verified transcriptional activity. The results of SDS-PAGE show that pET-28a-UrSTR recombinant protein was successfully expressed, and the size was anticipated. The UrSTR prokaryotic expression system needs to be optimized in the later stage. The research lays the foundation for further purification to study its structure and functional characterization of the UrSTR protein.

Cloning and subcellular location of the PnMYB1R1 gene from Panax notoginseng and expression analysis with different stresses / 药学学报

MYB transcription factors, one of the largest transcription factor families in plants, play an important role in signal transduction, plant growth and plant resistance. In this study a full-length cDNA of the PnMYB1R1 gene was cloned from Panax notoginseng. Sequence analysis, prokaryotic expression and purification, subcellular location, transcriptional activity analysis, tissue-specific analysis and expression analysis under different abiotic stresses was performed. The open reading frame (ORF) of PnMYB1R gene was 738 bp, encoding a protein of 245 amino acids with a predicted molecular mass (MW) of 27.0 kD. The sequence analysis and polygenetic analysis indicated that the PnMYB1R1 protein contains a conserved R3 domain, belonging to TRF-like protein in 1R-MYB-type transcription factors. The recombinant PnMYB1R1 protein was expressed in Escherichia coli BL21(DE3) cells using the prokaryotic expression vector pET28a-PnMYB1R1 and was purified. Subcellular localization analysis showed that PnMYB1R1 was localized in the nucleus. Transcriptional activity analysis indicated that the PnMYB1R1 transcription factor has transcriptional activation activity. Expression analysis indicated that PnMYB1R1 was primarily expressed in roots, followed by stems and leaves, and then rootlets. The expression level of PnMYB1R1 in root, stems, leaves and rootlets was influenced by salt, low temperature and drought treatment, while the abundance of PnMYB1R1 was significantly induced by salt stress in these tissues. These results provide valuable insights into the role of 1R-MYB transcription factors in plant defense.

Identificación de una triparedoxina peroxidasa citoplasmática en Leishmania braziliensis / Identification of a cytoplasmic tryparedoxin peroxidase from Leishmania braziliensis / Identificação de uma triparedoxina peroxidase citoplasmica de Leishmania braziliensis

Resumen Los sistemas de defensa anti-oxidante utilizados por el parásito intracelular Leishmania braziliensis durante el proceso de infección permiten eliminar especies reactivas de oxígeno y nitrógeno a expensas de equivalentes reductores derivados de la tripanotiona, evitando daños celulares del patógeno. Con el objetivo de identificar potenciales blancos moleculares para el desarrollo de fármacos contra este parásito, se realizó la detección de la enzima triparedoxina peroxidasa citoplasmática de L. braziliensis (LbTXNPxII), la cual es esencial para disminuir concentraciones tóxicas de peróxido de hidrógeno en el contexto de infección. Para esto se generaron anticuerpos policlonales en modelo aviar, partiendo de la clonación, expresión y purificación de la proteína recombinante 6xHis-SUMO-LbTXNPxII (37kDa) en el sistema heterólogo Escherichia coli. La proteína purificada se utilizó como antígeno para la producción de anticuerpos IgY, cuya implementación en estudios in situ permitió detectar y localizar la enzima LbTXNPxII endógena (22kDa) en el citoplasma de promastigotes fijados y verificar su interacción molecular con la nicotinamida/ nicotinato mononucleótido adenilil transferasa, enzima involucrada en la síntesis del NAD. De este modo, se reporta el desarrollo de una herramienta bioquímica para la identificación y estudio de la enzima LbTXNPxII y su participación en vías del metabolismo energético y de defensa anti-oxidante.

Abstract The antioxidant defense systems used by the intracellular parasite Leishmania braziliensis during the infection process make it possible to eliminate reactive oxygen and nitrogen species at the expense of reducing equivalents derived from trypanothione, avoiding cellular damage of the pathogen. In order to identify potential molecular targets for the development of drugs against this parasite, the cytoplasmic tryparedoxin peroxidase of L. braziliensis (LbTXNPxII), which is essential to reduce toxic concentrations of hydrogen peroxide in the context of infection, was carried out. In this regard, polyclonal antibodies were generated in an avian model, starting from the cloning, expression, and purification of the recombinant protein 6xHis-SUMO-LbTXNPxII (37kDa) in the heterologous system of Escherichia coli. The purified protein was used as an antigen for the production of IgY antibodies, whose implementation in in situ experiments allowed the detection and localization of the endogenous LbTXNPxII enzyme (22kDa) in the cytoplasm of fixed promastigotes, as well as the verification of its molecular interaction with nicotinamide/nicotinate mononucleotide adenylyltransferase, an enzyme involved in the synthesis of NAD. Thus, the development of a biochemical tool for the identification and study of the LbTXNPxII enzyme and its participation in energy metabolism and antioxidant defense pathways is reported.

Resumo Os sistemas de defesa antioxidante utilizados pelo parasita intracelular Leishmania braziliensis durante o processo de infecção, permitem a eliminação de espécies reativas de oxigênio e nitrogênio em detrimento de equivalentes redutores derivados de tripanotiona, evitando o dano celular do patógeno. Com o objetivo de identificar potenciais alvos moleculares para o desenvolvimento de drogas contra esse parasita, foi detectada a enzima citoplasmática triparedoxina peroxidase de L. braziliensis (LbTXNPxII), essencial para reduzir as concentrações tóxicas de peróxido de hidrogênio no contexto de infecção. Para isso, anticorpos policlonais foram gerados em modelo aviário, a partir da clonagem, expressão e purificação da proteína recombinante 6xHis-SUMO-LbTXNPxII (37kDa) no sistema heterólogo de Escherichia coli. A proteína purificada foi utilizada como antígeno para a produção de anticorpos IgY, cuja implementação em experimentos in situ permitiu a detecção e localização da enzima LbTXNPxII endógena (22kDa) no citoplasma de promastigotas fixos e verificar sua interação molecular com nicotinamida/nicotinato mononucleotídeo adenililtransferase, enzima envolvida na síntese de NAD. Assim, é relatado o desenvolvimento de uma ferramenta bioquímica para a identificação e estudo da enzima LbTXNPxII e sua participação no metabolismo energético e nas vias de defesa antioxidante.

Cloning and functional analysis of AaHSFB1 and its promoter in Amorphophallus / 生物工程学报

To explore the function of a heat shock transcription factor gene (HSFB1) and its promoter in Amorphophallus, a 1 365 bp DNA sequence was obtained by homologous cloning from Amorphophallus albus. The gene expression level of AaHSFB1 determined by qRT-PCR indicated that AaHSFB1 gene is more sensitive to heat stress. The expression level of AaHSFB1 in roots increased followed by a decrease upon heat treatment, and the highest expression level was observed after heat treatment for 1 h. The expression level of AaHSFB1 in leaves reached the highest after heat treatment for 12 h. The expression level in bulbs did not change greatly during the heat treatment. Subcellular localization analysis showed that AaHSFB1 protein was localized in the nucleus. A 1 509 bp DNA sequence which contains the AaHSFB1 promoter was obtained by FPNI-PCR method. Bioinformatics analysis showed that the promoter contained heat stress response elements HSE and a plurality of cis-acting elements related to plant development and stress response. A prAaHSFB1::GUS fusion expression vector was constructed to further analyze the function of AaHSFB1 promoter. The expression vector was transformed into Arabidopsis thaliana by Agrobacterium tumefaciens-mediated method, and GUS staining analysis on transgenic plants after heat treatment was performed. The results showed that AaHSFB1 promoter had very high activity in the leaves. Therefore, we speculate that AaHSFB1 may play an important role in the stress resistance of A. albus, especially when encountering heat stress.

VacPred: Sequence-based prediction of plant vacuole proteins using machine-learning techniques

Subcellular localization prediction of the proteome is one of major goals of large-scale genome or proteomesequencing projects to define the gene functions that could be possible with the help of computationalmodeling techniques. Previously, different methods have been developed for this purpose using multi-labelclassification system and achieved a high level of accuracy. However, during the validation of our blind datasetof plant vacuole proteins, we observed that they have poor performance with accuracy value range from*1.3% to 48.5%. The results showed that the previously developed methods are not very accurate for the plantvacuole protein prediction and thus emphasize the need to develop a more accurate and reliable algorithm. Inthis study, we have developed various compositions as well as PSSM-based models and achieved a highaccuracy than previously developed methods. We have shown that our best model achieved *63% accuracyon blind dataset, which is far better than currently available tools. Furthermore, we have implemented our bestmodels in the form of GUI-based free software called ‘VacPred’ which is compatible with both Linux andWindow platform. This software is freely available for download at www.deepaklab.com/vacpred.

Cloning, subcellular location and expression analysis of an acteoside synthase gene from Rehmannia glutinosa / 中草药

Objective: To clone the acteoside synthase gene (RgAcS1) from Rehmannia glutinosa, and analyze its subcellular localization and expression pattern. Methods: The cDNA sequence of RgAcS1 was identified based on the annotation of the transcriptome data of R. glutinosa, and the RgAcS1 gene was cloned by polymerase chain reaction (PCR). Constructing the GFP fusion expression vector and observing the subcellular localization of RgAcS1 mediated by Agrobacterium tumefaciens. The expression pattern of RgAcS1 in different parts of tuberous root of R. glutinosa was detected by real-time fluorescence quantitative PCR (qRT-PCR). Results: A full-length coding sequence of a shikimate-O-hydroxy cinnamoyl transferase from R. glutinosa was obtained and named RgAcS1. The length of the RgAcS1 cDNA was 1659 bp, including an open reading frame (ORF) of 1 296 bp, encoding 431 amino acid residues, the molecular weight of the protein was 475 900, and it has a typical domain of shikimic acid-O-hydroxy cinnamoyl transferase. The result of subcellular localization showed that RgAcS1 was mainly distributed in cytoplasm and also in nucleus. The qRT-PCR analysis showed that the expression levels of RgAcS1 were higher in the periderm and root hair of R. glutinosa tuberous root, but lower in the xylem and phloem. The expression levels of RgAcS1 were higher in non-radial striation than that in radial striation of BJ1, QH1 and 85-5. Conclusion: In this study, we obtained the cDNA sequence of RgAcS1, and analyzed the subcellular location and expression patterns of RgAcS1, which will lay foundations for further study on roles of RgAcS1 gene in the synthesis of acteoside in R. glutinosa.

Gene cloning, subcellular localization and expression analysis of the AsERF1 gene from Aquilaria sinensis / 药学学报

Ethylene-response factors, which are a subfamily of the AP2/ERF family, play an important role in ethylene signal transduction, plant growth and plant resistant. In this study, a full-length cDNA of the AsERF1 gene was cloned from Aquilaria sinensis. Sequence analysis, prokaryotic expression and purification, subcellular localization, tissue-specific analysis and expression analysis under different abiotic stresses was performed. The open reading frame (ORF) of the AsERF1 gene was 691 bp, encoding a protein of 229 amino acids with a predicted molecular mass of 25.36 kD. The AsERF1 protein contained the conserved AP2 sequence of ERF protein. A phylogenetic analysis indicated that the AsERF1 protein showed greatest sequence similarity with ERF2 from Populus trichocarpa. The recombinant AsERF1 protein was expressed in Escherichia coli BL21(DE3) cells using the prokaryotic expression vector pET28a-AsERF1 and the recombinant AsERF1 protein was purified. Agrobacterium-mediated protein expression experiments demonstrated that AsERF1 mainly localized to the nucleus. Expression analysis indicated that AsERF1 was primarily observed in leaves. The AsERF1 expression level was induced by salt, drought, low temperature and CdCl2 treatment, while the abundance of AsERF1 was most significantly induced by drought stress. These results provide valuable insights into the role of AsERF1 in plant defense and the mechanism of agarwood formation.

Experimental study of photodynamic therapy using a new photosensitizer BF01 for human liver cancer / 药学学报

We study here in vitro cytotoxicity, in vivo tumor inhibition and the mechanism on photodynamic therapy (PDT) of photosensitizer BF01 using human hepatocellular carcinoma cell line BEL-7402. CCK-8 method was used to detect the inhibition rate and IC50 in BEL-7402 cells on the same laser intensity with varying concentrations (0, 0.8, 1.6, 3.2, 6.4 μmol·L-1) of photosensitizer BF01. Cell death mode of BEL-7402 was detected by flow cytometry, with apoptotic characteristics observed by DAPI staining, and the subcellular localization of reactive oxygen was observed using photodynamic detection and confocal microscopy. The cell model of human liver cancer in nude mice was established, tumor growth curve was drawn, and the therapeutic effect of BF01 was determined. The animal experimentation was approved by East China University of Science and Technology Ethics Committee. The results indicated that BF01 PDT treatment can clearly inhibit BEL-7402 tumor cell proliferation, with the killing rate of 86% at the concentration of 6.4 μmol·L-1 of BF01, and half lethal concentration IC50 value of 2.46 μmol·L-1. DAPI stained nuclei shows the characteristics of advanced stage apoptosis, whereas reactive oxygen species level in the mitochondria increased with increasing drug concentration. In vivo experiments showed that photosensitizer BF01 mediated photodynamic therapy of liver cancer cells and inhibited tumor growth in mice. Therefore, the new BF01 photosensitizer has a potential for development into future clinic application.

Progress in endosomal Na⁺,K⁺/H⁺ antiporter in Arabidopsis thaliana / 生物工程学报

Important progress has been made in the interpretation of subcellular location, ion transport characteristics and biological functions of endosomal Na⁺,K⁺/H⁺ antiporter in Arabidopsis thaliana. The endosomal Na⁺,K⁺/H⁺ antiporter contain two members, AtNHX5 and AtNHX6, whose amino acid sequence similarity is 78.7%. Studies have shown that AtNHX5 and AtNHX6 are functionally redundant, and they are all located in Golgi, trans-Golgi network (TGN), endoplasmic reticulum (ER) and prevacuolar compartment (PVC). AtNHX5 and AtNHX6 are critical for salt tolerance stress and the homeostasis of pH and K⁺. It has been reported that there are conservative acidic amino acid residues that can regulate their ion activity in the endosomal NHXs transmembrane domain, which plays a decisive role in their own functions. The results of the latest research indicate that endosomal NHXs affect vacuolar transport and protein storage, and participate in the growth of auxin-mediated development in A. thaliana. In this paper, the progress of subcellular localization, ion transport, function and application of endosomal NHXs in A. thaliana was summarized.

Prediction of protein subcellular localization based on multilayer sparse coding / 生物工程学报

In order to provide a theoretical basis for better understanding the function and properties of proteins, we proposed a simple and effective feature extraction method for protein sequences to determine the subcellular localization of proteins. First, we introduced sparse coding combined with the information of amino acid composition to extract the feature values of protein sequences. Then the multilayer pooling integration was performed according to different sizes of dictionaries. Finally, the extracted feature values were sent into the support vector machine to test the effectiveness of our model. The success rates in data set ZD98, CH317 and Gram1253 were 95.9%, 93.4% and 94.7%, respectively as verified by the Jackknife test. Experiments showed that our method based on multilayer sparse coding can remarkably improve the accuracy of the prediction of protein subcellular localization.

Molecular cloning and subcellular localization of six HDACs and their roles in response to salt and drought stress in kenaf (Hibiscus cannabinus L)

BACKGROUND: Histone acetylation is an important epigenetic modification that regulates gene activity in response to stress. Histone acetylation levels are reversibly regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs). The imperative roles of HDACs in gene transcription, transcriptional regulation, growth and responses to stressful environment have been widely investigated in Arabidopsis. However, data regarding HDACs in kenaf crop has not been disclosed yet. RESULTS: In this study, six HDACs genes (HcHDA2, HcHDA6, HcHDA8, HcHDA9, HcHDA19, and HcSRT2) were isolated and characterized. Phylogenetic tree revealed that these HcHDACs shared high degree of sequence homology with those of Gossypium arboreum. Subcellular localization analysis showed that GFP-tagged HcHDA2 and HcHDA8 were predominantly localized in the nucleus, HcHDA6 and HcHDA19 in nucleus and cytosol. The HcHDA9 was found in both nucleus and plasma membranes. Real-time quantitative PCR showed that the six HcHDACs genes were expressed with distinct expression patterns across plant tissues. Furthermore, we determined differential accumulation of HcHDACs transcripts under salt and drought treatments, indicating that these enzymes may participate in the biological process under stress in kenaf. Finally, we showed that the levels of histone H3 and H4 acetylation were modulated by salt and drought stress in kenaf. CONCLUSIONS: We have isolated and characterized six HDACs genes from kenaf. These data showed that HDACs are imperative players for growth and development as well abiotic stress responses in kenaf.

Cloning,subcellular localization and spatio-temporal expression analysis of a flavonoid 3-O-glucosyltransferase gene( SmUF3GT) in Salvia miltiorrhiza / 中国中药杂志

The family of flavonoid 3-O-glucosyltransferase catalyzes the modification of anthocyanin from unstable-structure to stable-structure. In this study,based on homology cloning and transcriptome library,we isolated the full-length c DNA of UDP-glucose: flavonoid 3-O-glucosyltransferase( named SmUF3GT) from the flower tissues of S. miltiorrhiza. This gene was consisted of 1 353 bp open reading frames( ORF) encoding 450 amino acids. And the SmUF3GT protein was performed for the bioinformatic analysis. Our results showed that the protein was preliminary localized in the Golgi and peroxisome of cytosol,as well as plasma membrane and cell nuclear.QRT-PCR analyses indicated that SmUF3GT expressed differently in all tissues and organs but roots of S. miltiorrhiza and S. miltiorrhiza f.alba. During floral development,the expression of SmUF3GT showed a trend of rising fist and then down in purple-flower Danshen,whereas decreasing sharply fist and then slowly in white-flower Danshen. The present study provides basic information for further research on the network of synthesis and accumulation of flavonoids in S.miltiorrhiza.

Molecular cloning and characterization of 1-deoxy-D-xylulose 5-phosphate synthase gene from Taxus chinensis / 中草药

Objective To obatin the key enzymes of 1-deoxy-D-xylulose 5-phosphate synthase (DXS) in taxol biosynthetic pathway from Taxus chinensis (TcDXS), and carry out the bioinformatics analysis, tissue profile, subcellular localization, and functional complementation assay. Methods RACE technologies were used to obtain the full length cDNA of TcDXS for the bioinformatics analysis. Semi-quantitative PCR was used to detect the gene expression levels in different parts of T. chinensis. The localization and function of TcDXS were carried out by subcellular localization and functional complementation assay. Results The full-length cDNA of TcDXS was 3 031 bp containing a coding sequence of 2 229 bp encoding a 742-amino-acid residues which was predicted to have a molecular weight of 79 400 and an isoelectric point of 7.99. The qRT-PCR results showed that the highest expression level of TcDXS was detected in petioles and followed by leaves and barks. However, the expression of TcDXS was very low in roots and stems. What’s more, functional complementation assay results showed that the E. coli, co-transformed with PAC-BETA and pTrcTcDXS, was changed to orange. Conclusion TcDXS was considered to play an essential role in the control of taxol biosynthesis and provided a target for the metabolic engineering of taxol production and plant molecular breeding in T. chinensis.

Pig IFITMs are restriction factors for Japanese encephalitis virus

Objective:Japanese encephalitis virus (JEV) is responsible for one of the most serious epidemics of encephalitis in the world. JEV uses pigs as its main hosts and spreads among vertebrates and humans mediated by Culex mosquitoes. The prevention and control of JEV spread in pigs is one of the most effective measures to protect global public health. Interferon-inducible transmembrane proteins (IFITMs) are small membrane-spanning proteins that were identified as innate antiviral factors against multiple pathogenic viruses, especially enveloped viral pathogens. This study aims to verify whether pig interferon-inducible transmembrane proteins (pIFITMs) inhibit JEV and investigate the related molecular mechanisms of anti-JEV.Methods:Transient expression and RNA interference technology were used to overexpress and silence IFITMs gene. Three different cell lines, PK15, HEK293 and Huh7, were transfected with recombinant pIFITMs-expressing plasmids. The lentiviral vectors harboring RNAi sequences targeting pIFITMs were introduced into PK15 cells. Quantitative real-time PCR was used to determine the antiviral activities of pIFITMs through measuring and analyzing the virus copy number of JEV (SA14-14-2 strain) in the supernant of pIFITMs overexpression or silencing cells 48 hours post transfection. The expression of the related proteins was examined by western blot. The fusion vectors inserted with pig IFITM1-EGFP were constructed and introduced into three different cell lines respectively. Then Laser Co-focus light microscopy was used to observe the subcellular localization. The key active amino acids of pIFITM1 were analyzed by investigating the anti-JEV effect of the cysteine mutants produced with PCR site directed mutagenesistechnology.Results:In three different cell lines, PK15, HEK293 and Huh7, all of three pig IFITM proteins, pIFITM1, pIFITM2, and pIFITM3 could inhibit the replication of JEV whether through transient gene over-expression methods or RNA interference silencing. And that, among three pig IFITMs, pIFITM1 showed the strongest anti-JEV effect. The anti-JEV activity of pIFITM1 manifested at the early entry stage. In PK15, BHK21, and HEK293 cells, before virus infection, pIFITM1 was located in the plasma membrane area, and after infection, transferred to the membranous structures outside the nucleus. The S-palmitoylated cysteines at position 50, 51 and 84 of pIFITM1 had significant effect on virus replication.Conclusions:Pig interferon-inducible transmembrane proteins are restriction factors for JEV infection and have potentials in the prevention of virus spread. Our results provide some new sights into understanding the antiviral activity of pig IFITMs.