Structural and functional reorganization of inhibitory synapses by activity-dependent cleavage of neuroligin-2.

Recent evidence has demonstrated that the transsynaptic nanoscale organization of synaptic proteins plays a crucial role in regulating synaptic strength in excitatory synapses. However, the molecular mechanism underlying this transsynaptic nanostructure in inhibitory synapses still remains unclear and its impact on synapse function in physiological or pathological contexts has not been demonstrated. In this study, we utilized an engineered proteolysis technique to investigate the effects of acute cleavage of neuroligin-2 (NL2) on synaptic transmission. Our results show that the rapid cleavage of NL2 led to impaired synaptic transmission by reducing both neurotransmitter release probability and quantum size. These changes were attributed to the dispersion of RIM1/2 and GABAA receptors and a weakened spatial alignment between them at the subsynaptic scale, as observed through superresolution imaging and model simulations. Importantly, we found that endogenous NL2 undergoes rapid MMP9-dependent cleavage during epileptic activities, which further exacerbates the decrease in inhibitory transmission. Overall, our study demonstrates the significant impact of nanoscale structural reorganization on inhibitory transmission and unveils ongoing modulation of mature GABAergic synapses through active cleavage of NL2 in response to hyperactivity.

Long noncoding RNA SYISL regulates myogenesis by interacting with polycomb repressive complex 2.

Although many long noncoding RNAs (lncRNAs) have been identified in muscle, their physiological function and regulatory mechanisms remain largely unexplored. In this study, we systematically characterized the expression profiles of lncRNAs during C2C12 myoblast differentiation and identified an intronic lncRNA, SYISL (SYNPO2 intron sense-overlapping lncRNA), that is highly expressed in muscle. Functionally, SYISL promotes myoblast proliferation and fusion but inhibits myogenic differentiation. SYISL knockout in mice results in significantly increased muscle fiber density and muscle mass. Mechanistically, SYISL recruits the enhancer of zeste homolog 2 (EZH2) protein, the core component of polycomb repressive complex 2 (PRC2), to the promoters of the cell-cycle inhibitor gene p21 and muscle-specific genes such as myogenin (MyoG), muscle creatine kinase (MCK), and myosin heavy chain 4 (Myh4), leading to H3K27 trimethylation and epigenetic silencing of target genes. Taken together, our results reveal that SYISL is a repressor of muscle development and plays a vital role in PRC2-mediated myogenesis.

iTRAQ and RNA-Seq Analyses Provide New Insights into Regulation Mechanism of Symbiotic Germination of Dendrobium officinale Seeds (Orchidaceae).

Mycorrhizal fungi colonize orchid seeds and induce germination. This so-called symbiotic germination is a critical developmental process in the lifecycle of all orchid species. However, the molecular changes that occur during orchid seed symbiotic germination remain largely unknown. To better understand the molecular mechanism of orchid seed germination, we performed a comparative transcriptomic and proteomic analysis of the Chinese traditional medicinal orchid Dendrobium officinale to explore the change in protein expression at the different developmental stages during asymbiotic and symbiotic germination and identify the key proteins that regulate the symbiotic germination of orchid seeds. Among 2256 identified plant proteins, 308 were differentially expressed across three developmental stages during asymbiotic and symbiotic germination, and 229 were differentially expressed during symbiotic germination compared to asymbiotic development. Of these, 32 proteins were coup-regulated at both the proteomic and transcriptomic levels during symbiotic germination compared to asymbiotic germination. Our results suggest that symbiotic germination of D. officinale seeds shares a common signaling pathway with asymbiotic germination during the early germination stage. However, compared to asymbiotic germination, fungal colonization of orchid seeds appears to induce higher and earlier expression of some key proteins involved in lipid and carbohydrate metabolism and thus improves the efficiency of utilization of stored substances present in the embryo. This study provides new insight into the molecular basis of orchid seed germination.

[Cloning and bioinformatics analysis of 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase（PcHDR1）gene in Phlegmarirus carinatus].

The open reading frame of 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR) was cloned from Phlegmarirus carinatus by RT-PCR method and the sequence was analyzed by bioinformatics tools. After searching the transcriptome dataset of P. carinatus, one unique sequence encoding 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase was discovered. The primers were designed according to the cDNA sequence of 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase from the dataset. And then, the open reading frame (ORF) of 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase, named as PcHDR1 (GenBank Accession number：JQ957845), was cloned by RT-PCR strategy with the template of mixed RNA extracted from roots, stem and leaf of P. carinatus. The bioinformatic analysis of this gene and its corresponding protein was performed. The ORF of PcHDR1 consisted of 1 437 base pairs (bp), encoding one polypeptide with 478 amino acids. The sequence comparison showed that PcHDR1 is closest with GbHDR (Ginkgo biloba),and the sequence homology was up to 78%. Bioinformatics prediction and analysis indicated that PcHDR1 protein contained a conserved domain of LytB, without transmembrane region and signal peptides. This study cloned and analyzed 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase from P. carinatus. The result will provide a foundation for exploring the function of PcHDR1 involved in terpene biosynthesis in P. carinatus plants.

[Transcriptome characterization of Ephedra sinica with 454 ESTs].

Using the latest 454 GS FLX platform and Titanium regent, a substantial expressed sequence tag (ESTs) dataset of Ephedra sinica was produced, and the profile of gene expression and function gene of which were investigated. A total of 48 389 reads with an average length of 373 bp were generated. These 454 reads were assembled into 18 801 unigenes, which were all 454 sequencing identified. A total number of 10 531 unigenes(56.0%) were annotated using BLAST searches (E-value≤1×10⁻5) against the Nr, Nt, TAIR, SwissProt and KEGG databases. With respect to genes related to ephedrine biosynthesis, 19 unigenes(encoding 9 enzymes) were found. A total of 97 putative genes encoding cytochrome P450s were also discovered. Data presented in this study will provide an important resource for the scientific community that is interested in the functional genomics and secondary metabolism of E. sinica.

[Progress in the study of Velvet and LaeA proteins and their relation to the development and bioactive compounds in medicinal fungi].

The medicinal fungi, which are of great importance in traditional medicine, are facing the problems of wild resources scarcity and low concentration of bioactive compounds. Velvet family and LaeA global regulator play a vital role in secondary metabolism and developmental programs, which are found in a wide variety of fungi ranging from Chytridiomycota to Basidiomycota. This review elaborates the structures and functions between Velvet family and LaeA protein. The Velvet family which shares the Velvet protein domain, including VeA (Velvet), VelB (Velvet like B), VosA (viability of spores A) and VelC (Velvet like C), acts on the regulation function is secondary metabolism and developmental programs such as asexual and sexual development. Furthermore, the function is affected by environmental factors such as light and temperature. LaeA protein which owns S-adenosylmethionine-dependent methyltransferase domain, coordinately regulates development and secondary metabolism by regulating and modifying the Velvet proteins. The regulation of LaeA is mediated by light receptor proteins. Therefore, clarifying the mechanism of Velvet and LaeA proteins in medicinal fungi will pave the way for nurturing medicinal fungi and improving production of bioactive compounds.

[Research progress of the regulation on active compound biosynthesis by the bHLH transcription factors in plants].

Transcription factor is one of the key factors in the regulation of gene expression at the transcriptional level. It plays an important role in plant growth, active components biosynthesis and response to environmental change. This paper summarized the structure and classification of bHLH transcription factors and elaborated the research progress of bHLH transcription factors which regulate the active components in plants, such as flavonoids, alkaloids, and terpenoids. In addition, the possibility of increasing the concentration of active substances by bHLH in medicinal plants was assessed. The paper emphasized great significance of model plants and multidisciplinary research fields including modern genomics, transcriptomics, metabolomics and bioinformatics, providing the contribution to improve the discovery and function characterization of bHLH transcription factors. Accelerating the research in the mechanism of bHLH transcription factors on the regulation of active components biosynthesis will promote the development of breeding and variety improvement of Chinese medicinal materials, also ease the pressure of resources exhaustion of traditional Chinese medicine home and abroad.

Morphological and molecular analyses reveal two new species of Grifola (Polyporales) from Yunnan, China.

Species of Grifola are famous edible mushrooms and are deeply loved by consumers around the world. Most species of this genus have been described and recorded in Oceania, Europe and South America, with only Grifolafrondosa being recorded in Asia. In this study, two novel species of Grifola from southwestern China (Asia) are introduced. Macro and micromorphological characters are described. Grifolaedulissp. nov. present medium-size basidiomata with gray to gray-brown lobes upper surface, mostly tibiiform or narrowly clavate, rarely narrowly lageniform or ellipsoid chlamydospores, cuticle hyphae terminal segments slightly enlarged. Grifolasinensissp. nov. has white to grayish white lobes upper surface, mostly ellipsoid, rarely narrowly utriform chlamydospores, and broadly ellipsoid to ellipsoid basidiospores (4.6-7.9 × 3.0-5.9 µm). The two new species are supported by phylogenetic analyses of combined nuclear rDNA internal transcribed spacer ITS1-5.8S-ITS2 rDNA (ITS) and ß-tubulin (TUBB). Moreover, the genetic distance between TUBB sequences of those specimen from GenBank was 1.76-1.9%. Thus, the conspecificity relationship of our specimens remains uncertain, and further specimens are required to conclusively confirm its identity.

[Construction of the coexpression vector containing key element GLCYP450 involved in Ganoderma triterpene biosynthesis and its reductase gene GLNADPH].

Cytochrome P450 (CYP450) is a key element in the Ganoderma triterpenoid biosynthetic pathway. The catalytic reaction process for CYP450 requires NADPH / NADH for electron transfer. After searching the genome dataset of Ganoderma lucidum, the unique sequence encoding CYP450 and NADPH were discovered, separately. The open reading frames of GLCYP450 and GLNADPH were cloned separately using RT-PCR strategy from G lucidum. The appropriate restriction enzyme cutting sites were introduced at the 5' and 3' ends of gene sequence. The genes of GLCYP450 and GLNADPH were recombined into the yeast expression vector pESC-URA, leading to the formation of the yeast expression plasmid pESC-GLNADPH-GLCYP450. This study provides a foundation for researching Ganoderma triterpene biosynthesis using the approach of synthetic biology.

[Salvia miltiorrhiza as medicinal model plant].

Research on medicinal model organism is one of the core technologies to promote the modernization of traditional Chinese medicine (TCM). The research progress of Salvia miltiorrhiza as medicinal model plant is summarized in this paper. The genome of S. miltiorrhiza is small and its life cycle is short, as well as this plant can be stably genetically transformed. Because S. miltiorrhiza possesses the important medicinal and economic values, recently the transcriptome and genome of S. miltiorrhiza have been significantly recovered. The research prospect of S. miltiorrhiza as medicinal model plant in TCM was discussed, including biosynthesis of active components and their genetic regulation, relationship between quality of TCM and ecological environments, and selective breeding of good quality lines. Furthermore, as medicinal model plant, the construction of mutant library for S. miltiorrhiza, the genome map with high quality, and the functional genome should be investigated. Accompanying modern investigation of life sciences, the platform for medicinal model plant, S. miltiorrhiza, will be promoted to be established. It is important to develop the ethnopharmacology and new drugs around the world.

[Development of the devices for synthetic biology of triterpene saponins at an early stage: cloning and expression profiling of squalene epoxidase genes in panax notoginseng].

Synthetic biology of traditional Chinese medicine (TCM) is a new and developing subject based on the research of secondary metabolite biosynthesis for nature products. The early development of synthetic biology focused on the screening and modification of parts or devices, and establishment of standardized device libraries. Panax notoginseng (Burk.) F.H.Chen is one of the most famous medicinal plants in Panax species. Triterpene saponins have important pharmacological activities in P. notoginseng. Squalene epoxidase (SE) has been considered as a key rate-limiting enzyme in biosynthetic pathways of triterpene saponins and phytosterols. SE acts as one of necessary devices for biosynthesis of triterpene saponins and phytosterols in vitro via synthetic biology approach. Here we cloned two genes encoding squalene epoxidase (PnSE1 and PnSE2) and analyzed the predict amino acid sequences by bioinformatic analysis. Further, we detected the gene expression profiling in different organs and the expression level of SEs in leaves elicited by methyl jasmonate (MeJA) treatment in 4-year-old P notoginseng using real-time quantitative PCR (real-time PCR). The study will provide a foundation for discovery and modification of devices in previous research by TCM synthetic biology. PnSE1 and PnSE2 encoded predicted proteins of 537 and 545 amino acids, respectively. Two amino acid sequences predicted from PnSEs shared strong similarity (79%), but were highly divergent in N-terminal regions (the first 70 amino acids). The genes expression profiling detected by real-time PCR, PnSE1 mRNA abundantly accumulated in all organs, especially in flower. PnSE2 was only weakly expressed and preferentially in flower. MeJA treatment enhanced the accumulation of PnSEI mRNA expression level in leaves, while there is no obvious enhancement of PnSE2 in same condition. Results indicated that the gene expressions of PnSE1 and PnSE2 were differently transcribed in four organs, and two PnSEs differently responded to MeJA stimuli. It was strongly suggested that PnSEs play different roles in secondary metabolite biosynthesis in P. notoginseng. PnSE1 might be involved in triterpenoid biosynthesis and PnSE2 might be involved in phytosterol biosynthesis.

[Cloning and expression analysis of a key device of HMGR gene involved in ginsenoside biosynthesis of Panax ginseng via synthetic biology approach].

3-Hydroxy-3-methylglutaryl coenzyme-A reductase (HMGR), the first enzyme of mavalonic acid pathway, is one of the key devices involved in ginsenoside biosynthesis based on synthetic biology approach. The open reading frame of a novel HMGR gene from Panax ginseng (PgHMGR2) was cloned and analyzed in this study. PgHMGR2-encoding protein showed 71.6% sequence similarity to a P. ginseng HMGR in GenBank. The full-length cDNA sequence of PgHMGR2 containing 1 770 bp, which encodes 589 amino acids, was cloned by RT-PCR strategy from P. ginseng. The bioinformatic analysis showed that PgHMGR2-encoding protein contained two transmembrane regions and the HMG_CoA_reductase domain, without signal peptide. The protein sequence of PgHMGR2 had the highest sequence similarity (99%) with Panax quinquefolius HMGR (GenBank accession No. ACV65036). The expression level of PgHMGR2 was the highest in flower based on a real-time PCR analysis, followed by leaf and root, and the lowest was in stem. The result will provide a foundation for exploring the molecular function of PgHMGR2 involved in ginsenoside biosynthesis based on synthetic biology approach in P. ginseng plants.

[New technologies used for Panax genus research].

The authors reviewed the new technologies used for Panax genus research, including molecular identification technologies (especially for DNA barcoding), modern biotechnologies (e. g. the first generation and second generation sequencing technologies), and gene cloning and identification in this paper. These technologies have been successfully applied to species identification, transcriptome analysis, secondary metabolite biosynthetic pathway and the key enzyme function identification, indicating that the application of modern biotechnologies provide guarantee for the molecular identification of Panax genus. The application of modern biotechnologies also reveals the genetic information of transcriptome and functional genomics, and promotes the design of Panax plants genomic map. In summary, the application of the new technologies lay the foundation for clarifying the molecular mechanisms of ginsenoside biosynthesis and enforcing the in vitro synthesis of important natural products and new drugs in future.

Role and therapeutic target of P2X2/3 receptors in visceral pain.

Visceral pain (VP) is caused by internal organ disease. VP is involved in nerve conduction and related signaling molecules, but its specific pathogenesis has not yet been fully elucidated. Currently, there are no effective methods for treating VP. The role of P2X2/3 in VP has progressed. After visceral organs are subjected to noxious stimulation, cells release ATP, activate P2X2/3, enhance the sensitivity of peripheral receptors and the plasticity of neurons, enhance sensory information transmission, sensitize the central nervous system, and play an important role in the development of VP. However, antagonists possess the pharmacological effect of relieving pain. Therefore, in this review, we summarize the biological functions of P2X2/3 and discuss the intrinsic link between P2X2/3 and VP. Moreover, we focus on the pharmacological effects of P2X2/3 antagonists on VP therapy and provide a theoretical basis for its targeted therapy.

[Cloning and analysis of mevalonate kinase (PnMVK1) gene in Panax notoginseng].

Mevalonate kinase (MVK) is a key enzyme in plant terpenoid biosynthetic pathway. This study focused on cloning and analysis of Panax notoginseng (Burk.) F. H. Chen MVK (PnMVK1) gene. After searching the transcriptome dataset of P. notoginseng, one unique sequence encoding MVK was discovered. The primers were designed according to the transcript sequence of PnMVK1 from the P. notoginseng transcriptome dataset. And then, the open reading frame of PnMVK1 was cloned from P. notoginseng by using RT-PCR strategy. The physical and chemical properties, secondary structure and three-dimensional structure of the PnMVK1 protein were forecasted and analyzed, and its structure and function were predicted. The cDNA (named as PnMVK1) contains a 1164 bp open reading frame and encodes a predicted protein of 387 amino acids. The GenBank accession number for this gene is JQ957844. No transmembrane region and signal peptide were present in PnMVK1. The conserved domain of mevalonate kinase was present in PnMVK1. PnMVK1 was more abundant in P. notoginseng root than other organisms. This study cloned and analyzed PnMVK1 gene from P. notoginseng for the first time. The result will provide a foundation for exploring the mechanism of terpenoid biosynthesis in P. notoginseng plants.

[Full-length cDNA cloning and bioinformatics analysis of PnUGT1 gene in Panax notoginseng].

After searching the transcriptome dataset of Panax notoginseng, one unique sequence Pn02086 encoding UDP-glucosyltransferase (UGT), which may be involved in triterpene saponin biosynthesis, was discovered. The open reading frame of the UGT gene, named as PnUGT1, was cloned by 5'-RACE and RT-PCR method from P. notoginseng. The GenBank accession number for this gene is JX018210. The bioinformatic analysis of this gene and its corresponding protein was performed. The PnUGT1 gene contains a 1488 bp open reading frame and encodes a predicted protein of 495 amino acids. The molecular weight is 55.453 kD and the protein is unstable. In the secondary structure, the percentage of alpha helix, beta turn, random coil were 36.16%, 11.31%, 52.53%, respectively. The PnUGT1 contains 7 conserved domains predicted by InterProScan, including PSPG-box which is a unique consensus sequence of glycosyltransferases involved in plant secondary metabolism. The PnUGT1 was most likely to be located in the cytoplasm, without signal peptide and transmembrane region. Sequence alignment and phylogenetic analysis demonstrated that PnUGT1 had relative close relationship to the triterpene UDP-glucosyltransferase of Medicago truncatula (AAW56092), with the 66% similarity of conserved domain PSPG-box. PnUGT1 was more abundant in P. notoginseng leaf than in flower, stem and root. Therefore, PnUGT1 gene may be involved in notoginsenoside biosynthesis.

[Cloning and analysis of squalene synthase (HsSQS1) gene in Huperzia serrata].

Squalene synthase (SQS) is a key enzyme in plant terpenoid biosynthetic pathway. This study focused on cloning and analysis of Huperzia serrata SQS (HsSQS1) gene. After searching the transcriptome dataset of H serrata, one unique sequence encoding SQS was discovered. The primers were designed according to the transcript sequence of HsSQS1 from the H. serrata transcriptome dataset. The open reading frame of HsSQS1 was cloned using RT-PCR strategy. The bioinformatic analysis of this gene and its corresponding protein were performed. The cDNA (named as HsSQS1) contains a 1263 bp open reading frame and encodes a predicted protein of 420 amino acids. The GenBank accession number for this gene is JQ004938. HsSQS1 contains two transmembrane regions, without signal peptide. The conserved domain of squalene synthase was presented in HsSQS1. HsSQS1 was more abundant in H. serrata root than in leaf and stem. This study cloned and analyzed squalene synthase gene from H. serrata for the first time. The result will provide a foundation for exploring the mechanism ofterpenoid biosynthesis in H. serrata plants.

Spinal dI4 Interneuron Differentiation From Human Pluripotent Stem Cells.

Spinal interneurons (INs) form intricate local networks in the spinal cord and regulate not only the ascending and descending nerve transduction but also the central pattern generator function. They are therefore potential therapeutic targets in spinal cord injury and diseases. In this study, we devised a reproducible protocol to differentiate human pluripotent stem cells (hPSCs) from enriched spinal dI4 inhibitory GABAergic INs. The protocol is designed based on developmental principles and optimized by using small molecules to maximize its reproducibility. The protocol comprises induction of neuroepithelia, patterning of neuroepithelia to dorsal spinal progenitors, expansion of the progenitors in suspension, and finally differentiation into mature neurons. In particular, we employed both morphogen activators and inhibitors to restrict or "squeeze" the progenitor fate during the stage of neural patterning. We use retinoic acid (RA) which ventralizes cells up to the mid-dorsal region, with cyclopamine (CYC), an SHH inhibitor, to antagonize the ventralization effect of RA, yielding highly enriched dI4 progenitors (90% Ptf1a+, 90.7% Ascl1+). The ability to generate enriched spinal dI4 GABAergicINs will likely facilitate the study of human spinal IN development and regenerative therapies for traumatic injuries and diseases of the spinal cord.

Identification, Molecular Cloning, and Functional Characterization of a Coniferyl Alcohol Acyltransferase Involved in the Biosynthesis of Dibenzocyclooctadiene Lignans in Schisandra chinensis.

Schisandra chinensis owes its therapeutic efficacy to the dibenzocyclooctadiene lignans, which are limited to the Schisandraceae family and whose biosynthetic pathway has not been elucidated. Coniferyl alcohol is the synthetic precursor of various types of lignans and can be acetylated to form coniferyl acetate by coniferyl alcohol acyltransferase (CFAT), which belongs to the BAHD acyltransferase family. This catalytic reaction is important because it is the first committed step of the hypothetical biosynthetic pathway in which coniferyl alcohol gives rise to dibenzocyclooctadiene lignans. However, the gene encoding CFAT in S. chinensis has not been identified. In this study, firstly we identified 37 ScBAHD genes from the transcriptome datasets of S. chinensis. According to bioinformatics, phylogenetic, and expression profile analyses, 1 BAHD gene, named ScBAHD1, was cloned from S. chinensis. The heterologous expression in Escherichia coli and in vitro activity assays revealed that the recombinant enzyme of ScBAHD1 exhibits acetyltransferase activity with coniferyl alcohol and some other alcohol substrates by using acetyl-CoA as the acetyl donor, which indicates ScBAHD1 functions as ScCFAT. Subcellular localization analysis showed that ScCFAT is mainly located in the cytoplasm. In addition, we generated a three-dimensional (3D) structure of ScCFAT by homology modeling and explored the conformational interaction between protein and ligands by molecular docking simulations. Overall, this study identified the first enzyme with catalytic activity from the Schisandraceae family and laid foundations for future investigations to complete the biosynthetic pathway of dibenzocyclooctadiene lignans.

Mitochondrial dysfunction of induced pluripotent stem cells-based neurodegenerative disease modeling and therapeutic strategy.

Neurodegenerative diseases (NDDs) are disorders in which neurons are lost owing to various factors, resulting in a series of dysfunctions. Their rising prevalence and irreversibility have brought physical pain to patients and economic pressure to both individuals and society. However, the pathogenesis of NDDs has not yet been fully elucidated, hampering the use of precise medication. Induced pluripotent stem cell (IPSC) modeling provides a new method for drug discovery, and exploring the early pathological mechanisms including mitochondrial dysfunction, which is not only an early but a prominent pathological feature of NDDs. In this review, we summarize the iPSC modeling approach of Alzheimer's disease, Parkinson's disease, and Amyotrophic lateral sclerosis, as well as outline typical mitochondrial dysfunction and recapitulate corresponding therapeutic strategies.