RNA-binding Protein UNR Promotes Glioma Cell Migration and Regulates the Expression of Ribosomal Protein L9.

Objective To investigate the role of RNA binding protein─upstream-of-N-Ras (UNR) in the development of glioma and its molecular mechanism.Methods First, bioinformatics analysis of CGGA database was performed to detect UNR expression level and prognosis of patients with glioma. Western blot and real-time PCR were used to detect UNR expression level in glioma cell lines and tissues. Next, UNR siRNAs were transfected in glioma cells, and MTS assay and scratch wound-healing assay were used to detect changes in cell proliferation and migration. Then, the candidate UNR target mRNAs were identified by analyzing the sequencing data of UNR iCLIP-seq, RNA sequencing and ribosome profiling databases of human melanoma. RNA immunoprecipitation and biotin pull-down assays were used to identify the UNR target mRNAs in glioma cells. Finally, western blot was used to detect the effect of UNR knockdown on ribosomal protein L9 (RPL9) and RPL9 protein expression level in glioma cell lines. RPL9 siRNA was transfected in A172 and T98G and the expression of vimentin in the cells was detected with western blot.Results Bioinformatics analysis showed that UNR mRNA expression level was significantly higher in high-grade glioma [Grade 2 (n=126), Grade 3 (n=51), Grade 4 (n=128), P<0.001]. UNR high expression levels were associated with poor prognosis (P=0.0177). UNR had high expression level in glioma cell lines and patient samples compared with normal cell lines and normal brain samples (P<0.01). Knockdown of UNR inhibited glioma cells migration (P<0.05), but did not inhibit glioma cells growth in three glioma cell lines. UNR binded the 3' untranslated region (UTR) of PTEN and RPL9 mRNAs. RPL9 protein was significantly highly expressed in most glioma cell lines (n=9) and knockdown of UNR resulted in a downregulation of RPL9 protein expression. Epithelial-mesenchymal transition (EMT)-related marker─vimentin was positively regulated by RPL9.Conclusions UNR could bind to the 3'UTR of PTEN and RPL9 in glioma cell lines, therefore promoting glioma cell migration and regulating the expression of RPL9. Here, we establish a link between UNR and RPL9 protein, which will provide new ideas for the further study of glioma.

Mutation of the cellular adhesion molecule NECL2 is associated with neuromyelitis optica spectrum disorder.

AIMS: To investigate the association of the Nectin/Necl family genes with the risk of developing NMOSD. METHODS: Whole-exome sequencing was performed on two familial NMOSD cases and two unaffected family members. Additionally, 106 patients with sporadic NMOSD and 212 healthy controls (HCs) underwent screening for mutant Necl2. Finally, the molecular weight and cellular localization of mutant NECL2 was examined in transfected HeLa cells. RESULTS: We identified a novel deletion mutation in Necl2 (c.1052_1060delCCACCACCA; p. Thr351_Thr353del), which was associated with disease manifestation in the NMOSD familial cases. The frequency at which the mutation occurred in patients with sporadic NMOSD was significantly higher than for HCs (5.7% and 0, respectively; p<0.01). The mutation was located in the extracellular domain close to the transmembrane region, at a point in the protein sequence characterized by threonine enrichment. The mutant NECL2 had a lower molecular weight and exhibited defective trafficking to the cell surface. CONCLUSIONS: Our results suggest that the Necl2 mutation identified herein may be associated with the risk of developing NMOSD. Furthermore, mutated NECL2 may play a role in the pathogenesis of the disease, potentially through its roles in axonal regeneration and/or via neuron-glia interactions that are relevant to myelination.

DIXDC1 promotes retinoic acid-induced neuronal differentiation and inhibits gliogenesis in P19 cells.

Human DIXDC1 is a member of Dishevelled-Axin (DIX) domain containing gene family which plays important roles in Wnt signaling and neural development. In this report, we first confirmed that expression of Ccd1, a mouse homologous gene of DIXDC1, was up-regulated in embryonic developing nervous system. Further studies showed that Ccd1 was expressed specifically in neurons and colocalized with early neuronal marker Tuj1. During the aggregation induced by RA and neuronal differentiation of embryonic carcinoma P19 cells, expressions of Ccd1 as well as Wnt-1 and N-cadherin were dramatically increased. Stable overexpression of DIXDC1 in P19 cells promoted the neuronal differentiation. P19 cells overexpressing DIXDC1 but not the control P19 cells could differentiate into Tuj1 positive cells with RA induction for only 2 days. Meanwhile, we also found that overexpression of DIXDC1 facilitated the expression of Wnt1 and bHLHs during aggregation and differentiation, respectively, while inhibited gliogenesis by down-regulating the expression of GFAP in P19 cells. Thus, our finding suggested that DIXDC1 might play an important role during neurogenesis, overexpression of DIXDC1 in embryonic carcinoma P19 cells promoted neuronal differentiation, and inhibited gliogenesis induced by retinoic acid.

[Expression pattern of polycomb gene Nspc1 at the early developmental stage in zebrafish].

OBJECTIVE: To study the expression pattern of Polycomb gene Nspc1 at the early developmental stage in zebrafish. METHODS: In situ hybridization probe for Nspc1 was designed according to the GenBank information. Collecting zebrafish embryos at different stages including one cell stage, two-cell stage, bud stage, and somites stage, we hybridized them with the prepared probe. Then the hybridization signals at different intervals were observed and photographed at the right time. RESULTS: Nspc1 was expressed globally at the early stage. Its expression specificity began at the somites stage, mainly in the nervous system of the head. CONCLUSION: Nspc1 may play essential roles in the early stage development of zebrafish, especially in the nervous system.

[MiR-9 regulates the expression of CBX7 in human glioma].

OBJECTIVE: To detect the expression of CBX7 in human glioma and investigate the potential regulatory effect of abnormally expressed microRNAs on CBX7 expression. METHODS: Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot were applied to detect the expression pattern of CBX7 in 2 human normal brain tissues, 9 glioma tissues, and 3 glioma cell lines. Miranda algorithm and Ensemble Machine Learning algorithm were combined to predict miRNAs that target human CBX7. The expression of miR-9 in those tissues and cell lines were detected by real-time PCR. After miR-9 overexpression in 293ET and miR-9 knock-down in T98G, luciferase assay and Western blot were used to confirm the effect of miR-9 on CBX7 expression. MTT assay and flow cytometry were applied to detect the effect of miR-9 knock-down on T98G cells. RESULTS: No obvious difference in the CBX7 mRNA level between normal and tumor tissues was observed, while the protein level of CBX7 was abrogated or markedly reduced in glioma tissues and cell lines. Several miRNAs including miR-9 may target CBX7 by bioinformatics prediction. MiR-9 was up-regulated in glioma tissues and cell lines. In 293ET cell, luciferase activity of CBX7-3'UTR reporter was decreased to 24% after miR-9 overexpression. After miR-9 knock-down in T98G cell, the luciferase activity was increased by 1.8 fold and there was no change of CBX7 mRNA, while the protein level of endogenous CBX7 was significantly increased. The number of survival T98G cells increased and cells in G1 phase decreased after miR-9 knock-down. CONCLUSION: In human glioma, CBX7 is down-regulated by the inhibition of miR-9 at posttranscriptional level.

[Role of cell adhesion molecules Necl1 in synaptogenesis in primary cultured rat neurons].

OBJECTIVE: To study the role of cell adhesion molecules Necl1 in synaptogenesis in primary cultured neurons. METHODS: Semi-quantitive reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression pattern of Necl1 in the neuronal differentiation cell model in vitro. Western blot was performed to detect the expression pattern of Necl1 in primary cultured rat neurons and in purified synaptosome. Immunofluoresence was used to detect the synapse formation in primary neurons and in 293 cells co-culture and to detect the density of synapses in primary neuron with ectopic expression of Necl1. RESULTS: Necl1 expression increased after retinoic acid (RA) induction in SH-SY5Y and P19 cells. The increase of Necl1 expression was consistent with the days of primary neurons culture in vitro, and Necl1 partly localized in synaptosome. The overexpression of Necl1 in 293 cells induced the synapse formation between cocultured 293 cells and neurons. Ectopic expression of Necl1 in primary neurons increased the density of synapses. CONCLUSION: Necl1 plays an important role in neuronal synapse formation.

[Effect of NECL1 on the proliferation of T98G glioma cell line].

OBJECTIVE: To study the regulation role of tumor suppressor NECL1 on the proliferation of glioma cell line. METHODS: We detected the expression level of NECL1 in human normal brain tissue and glioma cell lines using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot. T98G cell line in which NECL1 was silent and whose transfection efficiency was relatively high as target cell was chosen, and the effect of NECL1 on the proliferation of T98G cell line in vitro was detected by using cell growth curve, flow cytometry, and Hoechst staining. RESULTS: NECL1 was abrogated or markedly reduced in 6 glioma cell lines. When NECL1 was overexpressed in T98G cell line, the cell growth rate obviously decreased and the number of apoptotic cells remarkably increased when compared with the control group. CONCLUSION: NECL1 may inhibit the proliferation of T98G cells by inducing its apoptosis.

MiRE: a graphical R package for microRNA-related analysis.

OBJECTIVE: To provide a set of useful analysis tools for the researchers to explore the microRNA data. METHODS: The R language was used for generating the Graphical Users Interface and implementing most functions. Some Practical Extraction and Report Language (Perl) scripts were used for parsing source files. RESULTS: We developed a graphical R package named miRE, which was designated for the analysis of microRNA functions, genomic organization, etc. This package provided effective and convenient tools for molecular biologists to deal with routine analyses in microRNA-related research. With its help, the users would be able to build a desktop-centered microRNA research environment quite easily and effectively. miRE is freely available at http://www. biosino.org/-kanghu/WorkPresentation/miRE/miRE.html. A detailed user manual and tutorials with example code and image are also available. CONCLUSION: miRE is a tool providing an open-source, user-friendly, integrated interface for microRNA-related analysis. With its help, researchers can perform microRNA-related analysis more efficiently.

[Bioluminescent imaging monitoring of a anti-angiogenesis therapeutic gene vasostatin in tumor cell PC3].

OBJECTIVE: To generate a sensitive tool for noninvasive monitoring of a therapeutic gene vasostatin. METHODS: We fused the bioluminescent reporter gene firefly luciferase to the therapeutic transgene vasostatin and ensured that these two proteins would not interrupt each other and kept their own natural character. RESULTS: We therefore examined clones of PC3 cells stably expressing fusion gene and positive controlfluc with bioluminescence. In vivo imaging of PC3-Fluc subcutaneous tumors showed that the mean tumor bioluminescence increased in animals over several weeks. CONCLUSION: Noninvasive monitoring facilitates the detection of gene expression in vivo and in vitro.

Common SNPs of APM1 gene are not associated with hypertension or obesity in Chinese population.

OBJECTIVE: To investigate whether the common variants 45T/G and 276G/T in APM1 gene were associated with hypertension combined with obesity (HO) and related clinical features in Chinese Han population. METHODS: A case-control study design was applied. Common polymorphisms of 45T/G and 276G/T were genotyped by PCR product sequencing in 484 cases with HO and 502 controls with normal blood presure and BMI < 25. RESULTS: The genotype and allele frequencies of 45T/G, 276G/T, and haplotype defined by the two variants in cases did not differ from those in controls. The means of blood pressure, BMI and waist-hip ratio did not differ among genotypes of the two polymorphisms and haplotypes. Among lipid profiles, only serum high-density lipoprotein cholesterol (HDL-C) levels were significantly lower in T allele carriers than that in non-T carriers after adjusting possible confounding factors (1.21 vs 1.32 mmol/L, P=0.0001). CONCLUSION: Polymorphisms of 45T/G and 276G/T in APM1 gene are not associated with hypertension or obesity, or their clinical features in Chinese Han population. Common polymorphism of 45T/G might be associated with serum HDL-C levels in Chinese.

Paraoxonase gene cluster variations associated with coronary heart disease in Chinese Han women.

BACKGROUND: The oxidative modification of low-density lipoprotein in the artery wall is currently believed to be central to the pathogenesis of atherosclerosis. Paraoxonase (PON1), an enzyme located on high-density lipoprotein (HDL), can prevent low-density lipoprotein (LDL) from oxidation at a certain extent. Recent studies show two other members of paraoxonase gene family, PON2 and PON3, possess antioxidant properties similar to PON1. The aim of the present study was to explore the role of PON gene cluster on coronary heart disease (CHD) in Chinese Han women. METHODS: Seven polymorphisms including PON1 -107C > T, -162G > A, -831G > A, R160G, Q192R, PON2 S311C, and PON3 -133C > A were genotyped in 184 female patients with CHD and 239 female controls. The plasma PON1 activity toward phenylacetate was determined in 50 cases and 50 controls randomly selected. RESULTS: The plasma PON1 activities were significantly lower in cases than in controls. Individual SNP analysis showed that cases had significantly higher frequencies of PON1 -107T, -831G and PON2 311S alleles than controls. The genotype distributions of -107C > T were also significantly different between two groups. The odds ratios for the development of CHD were 1.66 for -107TC carriers and 2.0 for -107TT carriers, compared with -107CC carriers. Haplotype analyses showed that the distributions of haplotypes comprised of PON1 -107C > T and PON2 S311C were significantly different between cases and controls, with cases having higher frequency of T-S haplotype (44.8% vs. 36.3%, P = 0.013). The T-S haplotype remained significantly associated with CHD after adjusting environmental risk factors (P = 0.0069). CONCLUSIONS: This association study suggested that lower plasma PON1 activity increased the risk of CHD in Chinese women, which may be mediated by the higher frequency of -107T allele in cases. Haplotype analyses indicated that there might be some synergistic effects between the PON1 -107C > T and PON2 S311C polymorphisms.

[Recombinant human pigment epithelium-derived factor inhibits the proliferation of the endothelial cells from blood vessels].

OBJECTIVE: To express and purify the recombinant human pigment epithelium-derived factor (PEDF) which inhibits the proliferation of the endothelium cells from blood vessel in E.coli. METHODS: PEDF gene was inserted into the prokaryotic expression vector pGEX-4T-2. The recombinant protein PEDF was expressed in E.coli BL-21, and purified by the GST Sepharose 4B affinity column. The recombinant human PEDF protein was identified by Western blot and mass spectrum. The biological activity of the recombinant human PEDF protein was measured by using MTT. RESULTS: The 46 kDa recombinant human PEDF protein was obtained. It significantly inhibited the proliferation of the human umbilical vein cell line HUVEC. CONCLUSION: The recombinant human PEDF with anti-angiogenesis activity protein may be successfully purify through prokaryotic expression.

The liver-enriched transcription factor CREB-H is a growth suppressor protein underexpressed in hepatocellular carcinoma.

We have previously characterized transcription factor LZIP to be a growth suppressor targeted by hepatitis C virus oncoprotein. In search of proteins closely related to LZIP, we have identified a liver-enriched transcription factor CREB-H. LZIP and CREB-H represent a new subfamily of bZIP factors. CREB-H activates transcription by binding to cAMP responsive element, box B, and ATF6-binding element. Interestingly, CREB-H has a putative transmembrane (TM) domain and it localizes ambiently to the endoplasmic reticulum. Proteolytic cleavage that removes the TM domain leads to nuclear translocation and activation of CREB-H. CREB-H activates the promoter of hepatic gluconeogenic enzyme phosphoenolpyruvate carboxykinase. This activation can be further stimulated by cAMP and protein kinase A. CREB-H transcript is exclusively abundant in adult liver. In contrast, the expression of CREB-H mRNA is aberrantly reduced in hepatoma tissues and cells. The enforced expression of CREB-H suppresses the proliferation of cultured hepatoma cells. Taken together, our findings suggest that the liver-enriched bZIP transcription factor CREB-H is a growth suppressor that plays a role in hepatic physiology and pathology.

[Analysis on the SARS-CoV genome of PUMC01 isolate].

OBJECTIVE: To perform variation and phylogenetics analysis on the SARS-CoV genome sequence (PUMC01) isolated in the Peking Union Medical College Hospital. METHODS: The cDNA library of SARS-CoV (PUMC01 isolate) was constructed by means of random-priming strategy. Random selected plasmid was sequenced and the genome sequence of SARS-CoV-PUMC01 was assembled by conventional methods (The Genebank Accession No. of SARS-CoV-PUMC01 is AY350750). The variation and phylogenetics analysis were performed by comparing the PUMC01 sequence with other SARS-CoV isolates. RESULTS: Ten variation sites were found by comparing PUMC01 isolate with Tor2 and Urbani isolates. In phylogenetic analysis of 18 SARS-CoV isolates, two classes were observed and there is different differential time between these two classes and the different isolates in each class. CONCLUSIONS: The evidence of phylogenetic analysis of different SARS-CoV isolates from different region is instructive for understanding the clinical relations between the different isolates and the transmission chain of SARS-CoV.

[cDNAs cloning of SARS-CoV PUMC2 viral genome].

OBJECTIVE: To get the cDNA clones which cover the whole genome of SARS-CoV PUMC2 strain. METHODS: Using the SARS-CoV PUMC2 strain genomic RNA as the template, the cDNA fragments were amplified by RT-PCR, the PCR products were further purified and ligated into the pGEM-T vector, and all the clones obtained were sequenced. RESULTS: The cDNA clones which cover the whole genome of SARS-CoV PUMC2 strain were obtained. CONCLUSIONS: These cDNAs can be provided for the function study of SARS-CoV proteins and the construction of full-length infectious cDNA clone of SARS-CoV.

[Cloning, expression and purification of SARS coronavirus PUMC2 strain nucleocapsid protein].

OBJECTIVE: To clone, express and purify nucleocapsid protein from SARS coronavirus PUMC2 strain. METHODS: According to the published SARS coronavirus genome sequences, the full length cDNA of N protein from SARS coronavirus PUMC2 strain was cloned by RT-PCR and the cDNA was cloned into the pET32a expression vector. The recombinant N protein was expressed in E. coli BL21 (DE3), and purified by Ni(2+)-NTA. RESULTS: Prokaryoticly expressed and purified N protein of SARS coronavirus PUMC2 strain was obtained. CONCLUSIONS: The SARS coronavirus recombinant N protein obtained by genetic engineering methods can be used for further functional study of SARS coronavirus N protein.

[Isolation and identification of SARS-coronavirus in nasal and throat swabs collected from clinically diagnosed SARS patients].

OBJECTIVE: To isolate and identify SARS-coronavirus in nasal and throat swabs collected from clinically diagnosed severe acute respiratory syndrome (SARS) patients. METHODS: Nasal and throat swab specimens were inoculated onto well of 24-well plate containing confluent monolayers of Vero and MRC-5 cells. Isolates were identified with serology, electron microscopy and genome sequence. RESULTS: One hundred and fifty-eight nasal and throat swabs specimens from 79 SARS patients in Peking Union Medical College Hospital between April and May, 2003 were cultured for SARS-coronavirus. Cytopathic effect (CPE) was found in three nasal swab specimens inoculated in Vero cells. Acute and convalescent phase serum specimens collected from SARS patients were found with seroconversions and/or a fourfold or greater rises in indirect fluorescence antibodies (IgG and IgM) titers when the 3 isolates (infected Vero cells) were used as antigen. Coronavirus was observed in the culture supernatant by negative-stain electron microscopy. Genome sequence confirmed the isolates were SARS-coronavirus. CONCLUSIONS: The 3 isolates from nasal and throat swabs samples collected from 79 clinically diagnosed SARS patients were SARS coronavirus.

[Cloning and expression of human single-chain Fv antibody against amyloid beta peptide involved in Alzheimer's disease].

OBJECTIVE: To screen out the specific antibody clones against amyloid beta peptide 40, and clone the antibody gene and express it in a bacterial system, so as to provide a solid basis for novel diagnostic and therapeutic methods for Alzheimer's Disease. METHODS: beta amyloid peptide 40 was bound on the solid surface of Nunc plates as antigen to screen the binding clones from a phage-display human single-chain Fv antibody library. After five rounds of bio-panning, the host E. coli TG1 was infected with eluted filamentous phage from the last turn of selection. 55 well-separated colonies were picked randomly from the plates and the specific positive clones were identified by ELISA test. The single-chain Fv antibody gene was sequenced and their amino acids sequence was deduced. The scFv antibody gene was sub-cloned into a protokayotic expression vector pGEX-6P-1 and transformed into bacteria strain BL21 to express the glutathione-S-transferase (GST) fusion single-chain antibody. RESULTS: ELISA test showed that 33 of the 55 clones could bind amyloid beta peptide 40 and 10 of the 33 clones could be inhibited by amyloid beta peptide 40 itself to below 50% of its original binding activities. Five of the 10 clones could also be inhibited by amyloid beta peptide 1-16 to the same level, which meant that the binding epitope of the antibody from the 5 clones was between first to sixteenth amino acids at amino-end of amyloid beta peptide 40. DNA sequencing data demonstrated that the gene of the single-chain antibody specifically against amyloid beta peptide 40 was consisted of 768 bp and the deduced amino acids sequence confirmed its typical antibody structure. The complement determinant regions and framework regions were discriminated empirically. After cloning the antibody gene into a protokayotic system, the GST fusion antibody was expressed as the expected size. CONCLUSIONS: After five rounds of bio-panning and subsequently serial ELISA testing, the specific antibody clones against amyloid beta peptide 40 were screened out successfully. The antibody gene DNA sequence and amino acids sequence were analyzed and confirmed. The fusion antibody was expressed as expected in the bacterial system.

Protein kinase C/zeta (PRKCZ) gene is associated with type 2 diabetes in Han population of North China and analysis of its haplotypes.

AIM: To identify the susceptible gene (s) for type 2 diabetes in the previously mapped region, 1p36.33-p36.23, in Han population of North China using single nucleotide polymorphisms (SNPs) and to analyze the haplotypes of the gene (s) related to type 2 diabetes. METHODS: Twenty three SNPs located in 10 candidate genes in the mapped region were chosen from public SNP domains with bioinformatic methods, and the single base extension (SBE) method was used to genotype the loci for 192 sporadic type 2 diabetes patients and 172 normal individuals, all with Han ethical origin, to perform this case-control study. The haplotypes with significant difference in the gene (s) were further analyzed. RESULTS: Among the 23 SNPs, 8 were found to be common in Chinese Han population. Allele frequency of one SNP, rs436045 in the protein kinase C/zetagene (PRKCZ) was statistically different between the case and control groups(P<0.05). Furthermore, haplotypes at five SNP sites of PRKCZ gene were identified. CONCLUSION: PRKCZ gene may be associated with type 2 diabetes in Han population in North China. The haplotypes at five SNP sites in this gene may be responsible for this association.

Unique physiological and pathogenic features of Leptospira interrogans revealed by whole-genome sequencing.

Leptospirosis is a widely spread disease of global concern. Infection causes flu-like episodes with frequent severe renal and hepatic damage, such as haemorrhage and jaundice. In more severe cases, massive pulmonary haemorrhages, including fatal sudden haemoptysis, can occur. Here we report the complete genomic sequence of a representative virulent serovar type strain (Lai) of Leptospira interrogans serogroup Icterohaemorrhagiae consisting of a 4.33-megabase large chromosome and a 359-kilobase small chromosome, with a total of 4,768 predicted genes. In terms of the genetic determinants of physiological characteristics, the facultatively parasitic L. interrogans differs extensively from two other strictly parasitic pathogenic spirochaetes, Treponema pallidum and Borrelia burgdorferi, although similarities exist in the genes that govern their unique morphological features. A comprehensive analysis of the L. interrogans genes for chemotaxis/motility and lipopolysaccharide synthesis provides a basis for in-depth studies of virulence and pathogenesis. The discovery of a series of genes possibly related to adhesion, invasion and the haematological changes that characterize leptospirosis has provided clues about how an environmental organism might evolve into an important human pathogen.