Biomedical subjects

Boqin Qiang

Publications and source records attributed to Boqin Qiang.

At least 19 recordsLinked to original sources

PubMed2007

Renalase gene is a novel susceptibility gene for essential hypertension: a two-stage association study in northern Han Chinese population.

Renalase, a novel flavin adenine dinucleotide-dependent amine oxidase, is secreted by the kidney, degrades circulating catecholamines, and modulates cardiac function and systemic blood pressure (BP). Its discovery may provide novel insights into the mechanisms of BP regulation and the pathogenesis of essential hypertension (EH). We designed a two-stage case-control study to investigate whether the renalase gene harbored any genetic variants associated with EH in the northern Han Chinese population. From the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA in China), 1,317 hypertensive cases and 1,269 normotensive controls were recruited. These total 2,586 subjects were taken as the main study population in this study. In stage 1, all the eight selected single nucleotide polymorphisms (SNPs) of the renalase gene were genotyped and tested within a subsample (503 cases and 490 controls) of the main study population. By single locus analyses, three SNPs, rs2576178, rs2296545, and rs2114406, showed significant associations with EH (P < 0.05). In stage 2, these three SNPs were genotyped on the remaining individuals and analyzed using all the individuals. After Bonferroni correction for multiple comparisons, the associations of rs2576178 and rs2296545 with EH were still significant in stage 2. The cases had higher frequencies of rs2576178 G allele and rs2296545 C allele than the controls (0.55 versus 0.49, P < 0.0001; 0.61 versus 0.55, P < 0.0001). Particularly, under the codominant model, the adjusted odds ratios for rs2576178 GG genotype and rs2296545 CC genotype were 1.58 (95% CI, 1.25 to 2.00; P = 0.0002) and 1.61 (95% CI, 1.26 to 2.04; P = 0.0002), respectively. We also found risk-associated haplotypes and diplotypes, which further confirmed the significant association between the renalase gene and EH. These findings may provide novel genetic susceptibility markers for EH and lead to a better understanding of EH pathophysiology. In addition, further replications in other populations and functional studies would be warranted.

Adult↗

PubMed2007

Selective expression of Bhlhb5 in subsets of early-born interneurons and late-born association neurons in the spinal cord.

Accumulating evidence has suggested that the basic helix-loop-helix transcription factors play important roles in controlling neuronal fate specification and differentiation in the developing central nervous system. In this study, we report a detailed immunological study on the expression of Bhlhb5 in embryonic mouse spinal cord with a newly developed antibody. At the early stage of neural development, Bhlhb5 is specifically expressed in dI6 dorsal interneurons and in V1 and V2 ventral interneurons. At late stages of development, Bhlhb5 expression is detected in a subset of late-born dorsal association interneurons that migrate into the uppermost layer of the dorsal horn.

Animals↗

PubMed2006

NSPc1 is a cell growth regulator that acts as a transcriptional repressor of p21Waf1/Cip1 via the RARE element.

The mammalian polycomb group proteins play an important role in cell cycle control and tumorigenesis. Nervous system polycomb 1 (NSPc1) is a newly identified transcription repressor, highly homologous with PcG protein Bmi-1. In this article, we showed that NSPc1 could promote tumor cell cycle progression and cell proliferation. Semi-quantitative RT-PCR showed that NSPc1 did not affect the expression levels of most Cyclin-depentent kinases (CDK) inhibitors except for p21Waf1/Cip1. Repression activity assays, chromatin immunoprecipitation (ChIP) and DNA pulldown assays all verified that NSPc1 represses the expression of p21Waf1/Cip1 by binding to the (-1357 to -1083) region of the p21Waf1/Cip1 promoter in vivo, and the repression effect is dependent on the retinoid acid response element (RARE element) within the above region of the p21Waf1/Cip1 promoter. Further analysis showed that NSPc1 could compete the RARE element site with RA receptors both in vitro and in vivo. Taken together, our results support the hypothesis that NSPc1 has a positive role in tumor cell growth by down-regulating p21Waf1/Cip1 via the RARE element, which directly connects transcriptional repression of PcGs to CDKIs and RA signaling pathways.

Animals↗

PubMed2006

Identification and characterization of selenoprotein K: an antioxidant in cardiomyocytes.

Selenoprotein K (SelK) is a newly identified selenoprotein. We showed that selenium incorporation into SelK was dependent on the 3'UTR of SelK mRNA. Sec insertion sequence (SECIS) RNA binding assays demonstrated that human SBP2 bound to the SelK SECIS element through the conserved non-Watson-Crick base pair quartet but not the AAT motif. Examination of the expression pattern revealed that human SelK mRNA was highly expressed in heart. Immunofluorescence analysis showed that SelK localized to the endoplasmic reticulum. Using SelK recombinant adenovirus, we found that overexpression of SelK attenuated the intracellular reactive oxygen species level and protected cells from oxidative stress-induced toxicity in cardiomyocytes. Our findings indicated that SelK is a novel antioxidant in cardiomyocytes and is related to the regulation of cellular redox balance.

3' Untranslated Regions↗

PubMed2006

Dok5 is substrate of TrkB and TrkC receptors and involved in neurotrophin induced MAPK activation.

Tropomyosin-related kinase (Trk) family receptors are a group of high affinity receptors for neurotrophin growth factors, which have pivotal functions in many physiological processes of nervous system. Trk receptors can dimerize and autophosphorylate upon neurotrophin stimulation, then recruit multiple adaptor proteins to transduct signal. In this report, we identified Dok5, a member of Dok family, as a new substrate of TrkB/C receptors. In yeast two-hybrid assay, Dok5 can interact with intracellular domain of TrkB and TrkC receptor through its PTB domain, but not with that of TrkA receptor. The interaction was then confirmed by GST pull-down assay and Co-IP experiment. Dok5 co-localized with TrkB and TrkC in differentiated PC12 cells, providing another evidence for their interaction. By using mutational analysis, we characterized that Dok5 PTB domain bound to Trk receptor NPQY motif in a kinase-activity-dependent manner. Furthermore, competition experiment indicated that Dok5 competed with N-shc for binding to the receptors at the same site. Finally, we showed that Dok5 was involved in the activation of MAPK pathway induced by neurotrophin stimulation. Taken together, these results suggest that Dok5 acts as substrate of TrkB/C receptors and is involved in neurotrophin induced MAPK signal pathway activation.

Adaptor Proteins, Signal Transducing↗

PubMed2006

The DNA sequence, annotation and analysis of human chromosome 3.

After the completion of a draft human genome sequence, the International Human Genome Sequencing Consortium has proceeded to finish and annotate each of the 24 chromosomes comprising the human genome. Here we describe the sequencing and analysis of human chromosome 3, one of the largest human chromosomes. Chromosome 3 comprises just four contigs, one of which currently represents the longest unbroken stretch of finished DNA sequence known so far. The chromosome is remarkable in having the lowest rate of segmental duplication in the genome. It also includes a chemokine receptor gene cluster as well as numerous loci involved in multiple human cancers such as the gene encoding FHIT, which contains the most common constitutive fragile site in the genome, FRA3B. Using genomic sequence from chimpanzee and rhesus macaque, we were able to characterize the breakpoints defining a large pericentric inversion that occurred some time after the split of Homininae from Ponginae, and propose an evolutionary history of the inversion.

Animals↗

PubMed2006

Association study with 33 single-nucleotide polymorphisms in 11 candidate genes for hypertension in Chinese.

Essential hypertension is considered to be a typical complex disease with multifactorial etiology, which leads to inconsistent findings in genetic studies. One possibility of failure to replicate some single-locus results is that the underlying genetics of hypertension are not only based on multiple genes with minor effects but also on gene-gene interactions. To test this hypothesis, a case-control study was constructed in Chinese subjects, detecting both single locus and multilocus effects. Eleven candidate genes were selected from biochemical pathways that have been implicated in the development and progression of hypertension, and 33 polymorphisms were evaluated in 503 hypertension patients and 490 age- and gender-matched controls. Single-locus associations, using traditional logistic regression analyses, and multilocus associations, using classification and regression trees and multivariate adaptive regression splines, were both explored in this study. Final models were selected using either Bonferroni correction or cross-validation. Three polymorphisms, TH*rs2070762, ADRB2*Q27E, and GRK4*A486V, were found to be independently associated with essential hypertension in Chinese subjects. In addition to these individual predictors, a potential interaction of CYP11B2-AGTR1 is also involved in the etiology of hypertension. These findings support the multigenic nature of the etiology of essential hypertension and propose a potential gene-gene interactive model for future studies.

Alanine↗

PubMed2006

Crystal structure of the V domain of human Nectin-like molecule-1/Syncam3/Tsll1/Igsf4b, a neural tissue-specific immunoglobulin-like cell-cell adhesion molecule.

Nectins are Ca(2+)-independent immunoglobulin (Ig) superfamily proteins that participate in the organization of epithelial and endothelial junctions. Nectins have three Ig-like domains in the extracellular region, and the first one is essential in cell-cell adhesion and plays a central role in the interaction with the envelope glycoprotein D of several viruses. Five Nectin-like molecules (Necl-1 through -5) with similar domain structures to those of Nectins have been identified. Necl-1 is specifically expressed in neural tissue, has Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity, and plays an important role in the formation of synapses, axon bundles, and myelinated axons. Here we report the first crystal structure of its N-terminal Ig-like V domain at 2.4 A, providing insight into trans-cellular recognition mediated by Necl-1. The protein crystallized as a dimer, and the dimeric form was confirmed by size-exclusion chromatography and chemical cross-linking experiments, indicating this V domain is sufficient for homophilic interaction. Mutagenesis work demonstrated that Phe(82) is a key residue for the adhesion activity of Necl-1. A model for homophilic adhesion of Necl-1 at synapses is proposed based on its structure and previous studies.

Amino Acid Sequence↗

PubMed2006

SARS-CoV nucleocapsid protein binds to hUbc9, a ubiquitin conjugating enzyme of the sumoylation system.

SARS-CoV is a newly identified coronavirus (CoV) that causes severe acute respiratory syndrome (SARS). The SARS-CoV nucleocapsid (N) protein is an important structural and functional protein. To identify cellular proteins that interact with the SARS-CoV N protein and to elucidate the possible involvement of N protein in SARS-CoV pathogenesis, a human lymphocyte cDNA library was screened using a yeast two-hybrid system assay. hUbc9, a ubiquitin conjugating enzyme of sumoylation system, was found to interact specifically with the N protein, implying the post-translational sumoylation of the N protein. Mapping studies localized the critical N sequences for this interaction to amino acids 170-210, which includes the SR-rich motif. However, the consensus motif of sumoylation GK(62)EE in the N protein is not responsible for binding to hUbc9. Mutations of hUbc9 at the enzyme active site C93A or C93S severely impair the interaction with the N protein. The two proteins were also shown to colocalize in the cytoplasm of the transfected 293T cells. This is the first report demonstrating the interaction of hUbc9 with a structural protein of plus-strand RNA viruses, indicating a new drug target for SARS-CoV.

Binding Sites↗

PubMed2006

Association of alpha1A adrenergic receptor gene variants on chromosome 8p21 with human stage 2 hypertension.

OBJECTIVE AND DESIGN: We previously reported a significant linkage between human chromosome 8p22 with essential hypertension and systolic blood pressure levels. On the basis of this, we used an efficient age, sex and area-matched case-control scheme to test the association of the polymorphisms in the human alpha1A adrenergic receptor (ADRA1A) gene, located on chromosome 8p21-p11.2, with essential hypertension in a northern Han Chinese population. METHODS: Seven polymorphisms were identified by direct sequencing of genomic DNA derived from 48 randomly recruited hypertensive and 48 healthy subjects. They were also examined for association with essential hypertension in 480 stage 2 hypertensive individuals and their individually matched controls. RESULTS: We observed significantly higher frequencies of the 347Arg allele and 2547G alleles in the cases compared with their controls (P = 0.04 and 0.007, respectively). McNemar's test revealed that carriers of 2547G alleles were at a greater risk of essential hypertension with an odds ratio of 3.00 [95% confidence interval (CI) 1.23-8.35]. We then performed a conditional logistic regression to adjust the effects of conventional risk factors, revealing an odds ratio of 2.84 for carriers of the 2547G allele (95% CI 1.15-6.99). With the haplotypic probabilities estimated using PHASE software, we performed haplotype trend regression analysis, showing a significant association between haplotype 7 and essential hypertension (P = 0.02), after adjustment for conventional risk factors. CONCLUSIONS: Our findings suggest that the genetic variations in the ADRA1A gene are significantly associated with essential hypertension, and may play an important role in the development of essential hypertension in this Chinese population.

Case-Control Studies↗

PubMed2005

Genome dynamics and diversity of Shigella species, the etiologic agents of bacillary dysentery.

The Shigella bacteria cause bacillary dysentery, which remains a significant threat to public health. The genus status and species classification appear no longer valid, as compelling evidence indicates that Shigella, as well as enteroinvasive Escherichia coli, are derived from multiple origins of E.coli and form a single pathovar. Nevertheless, Shigella dysenteriae serotype 1 causes deadly epidemics but Shigella boydii is restricted to the Indian subcontinent, while Shigella flexneri and Shigella sonnei are prevalent in developing and developed countries respectively. To begin to explain these distinctive epidemiological and pathological features at the genome level, we have carried out comparative genomics on four representative strains. Each of the Shigella genomes includes a virulence plasmid that encodes conserved primary virulence determinants. The Shigella chromosomes share most of their genes with that of E.coli K12 strain MG1655, but each has over 200 pseudogenes, 300 approximately 700 copies of insertion sequence (IS) elements, and numerous deletions, insertions, translocations and inversions. There is extensive diversity of putative virulence genes, mostly acquired via bacteriophage-mediated lateral gene transfer. Hence, via convergent evolution involving gain and loss of functions, through bacteriophage-mediated gene acquisition, IS-mediated DNA rearrangements and formation of pseudogenes, the Shigella spp. became highly specific human pathogens with variable epidemiological and pathological features.

DNA Transposable Elements↗

PubMed2005

Characterization and crystallization of human DPY-30-like protein, an essential component of dosage compensation complex.

Human DPY-30-like is a homolog of C. elegans DPY-30. DPY-30 is an essential component of dosage compensation machinery and loss of dpy-30 activity results in XX-specific lethality. In XO animals, DPY-30 is required for developmental processes other than dosage compensation. In yeast, the homolog of DPY-30, Saf19p, functions as a member of histone 3 lysine 4 methylation complex, which is the key part of epigenetic developmental control. In this report, human DPY-30-like protein was overexpressed and purified with the goal of structure determination. It was crystallized at 291 K in hanging drops by the vapour diffusion technique from a precipitant solution consisting of (NH4)2SO4 (1.5-2.0 M), Tris-HCl (0.1 M, pH 8.0). The crystal diffracted to 2.7 A resolution at 100 K in-house and belongs to the space group P4(1)2(1)2 or P4(3)2(1)2 with unit-cell parameters of a=b=74.5 A, c=87.0 A, alpha=beta=gamma=90.0 degrees. The asymmetric unit contains two molecules with 49% solvent content. We also analyzed its biochemical and biophysical characterizations. Efforts are now under way to determine the molecular structure of the DPY-30-like. These studies will open a new avenue towards the structure-based functional analysis of human DPY-30-like and dosage compensation machinery.

Animals↗

PubMed2005

Comparative and functional genomic analyses of the pathogenicity of phytopathogen Xanthomonas campestris pv. campestris.

Xanthomonas campestris pathovar campestris (Xcc) is the causative agent of crucifer black rot disease, which causes severe losses in agricultural yield world-wide. This bacterium is a model organism for studying plant-bacteria interactions. We sequenced the complete genome of Xcc 8004 (5,148,708 bp), which is highly conserved relative to that of Xcc ATCC 33913. Comparative genomics analysis indicated that, in addition to a significant genomic-scale rearrangement cross the replication axis between two IS1478 elements, loss and acquisition of blocks of genes, rather than point mutations, constitute the main genetic variation between the two Xcc strains. Screening of a high-density transposon insertional mutant library (16,512 clones) of Xcc 8004 against a host plant (Brassica oleraceae) identified 75 nonredundant, single-copy insertions in protein-coding sequences (CDSs) and intergenic regions. In addition to known virulence factors, full virulence was found to require several additional metabolic pathways and regulatory systems, such as fatty acid degradation, type IV secretion system, cell signaling, and amino acids and nucleotide metabolism. Among the identified pathogenicity-related genes, three of unknown function were found in Xcc 8004-specific chromosomal segments, revealing a direct correlation between genomic dynamics and Xcc virulence. The present combination of comparative and functional genomic analyses provides valuable information about the genetic basis of Xcc pathogenicity, which may offer novel insight toward the development of efficient methods for prevention of this important plant disease.

Bacterial Proteins↗

PubMed2005

Nectin-like molecule 1 is a protein 4.1N associated protein and recruits protein 4.1N from cytoplasm to the plasma membrane.

Nectins are immunoglobulin superfamily adhesion molecules that participate in the organization of epithelial and endothelial junctions. Sharing high homology with the poliovirus receptor (PVR/CD155), nectins were also named poliovirus receptor-related proteins (PRRs). Four nectins and five nectin-like molecules have been identified. Here we describe the cloning and characterization of human and mouse nectin-like molecular 1 (NECL1). Human and mouse NECL1 share 87.3% identity at the amino acid level. NECL1 contains an ectodomain made of three immunoglobulin-like domains, and a cytoplasmic region homologous to those of glycophorin C and contactin-associated protein. RNA blot and in situ hybridization analysis showed that NECL1 predominantly expressed in the central nervous system, mainly in neuronal cell bodies in a variety of brain regions including the cerebellum, cerebral cortex and hippocampus. In vitro binding assay proved the association of NECL1 with protein 4.1N. NECL1 localizes to the cell-cell junctions and recruits protein 4.1N to the plasma membranes through its C-terminus, thus may regulate the function of the cell-cell junction. We propose that the NECL1 and protein 4.1N complex is involved in the morphological development, stability, and dynamic plasticity of the nervous system.

Amino Acid Sequence↗

PubMed2005

NSPc1, a mainly nuclear localized protein of novel PcG family members, has a transcription repression activity related to its PKC phosphorylation site at S183.

Nervous system polycomb 1 (NSPc1) shares high homology with vertebrate PcG proteins Mel-18 and Bmi-1. The mRNA of NSPc1 is highly expressed in the developmental nervous system [Mech. Dev. 102 (2001) 219-222]. However, the functional characterization of NSPc1 protein is not clear. In the present study, using Western blotting technique, we aimed to describe the distributions of NSPc1 protein in rat tissues and cell lines. The subcellular localization of NSPc1 was examined in HeLa and SH-SY5Ycell lines, and its transcriptional repression activity was examined in COS-7 cell line. We found that the NSPc1 protein was localized mainly in the nucleus. NSPc1 remarkably repressed the transcription. Most interestingly, both the C-terminal of NSPc1 and two phosphorylation sites in the C-terminal, especially the PKC phosphorylation site at S183, were important in mediating transcription repression. Taken together, results from our study suggest that NSPc1, as a typical PcG family member, has powerful transcriptional repression ability, which may be related to the PKC signaling pathway.

Animals↗

PubMed2005

Identification of functional genetic variants in cyclooxygenase-2 and their association with risk of esophageal cancer.

BACKGROUND & AIMS: Overexpression of cyclooxygenase-2 (COX-2) is implicated in many steps of cancer development. Single nucleotide polymorphisms (SNPs) in the COX-2 promoter might contribute to differential COX-2 expression and subsequent interindividual variability in susceptibility to cancer. This study sought to identify functional SNPs in the COX-2 promoter and evaluated their effects on the risk of developing esophageal squamous cell carcinoma (ESCC). METHODS: Thirty individual DNA samples were sequenced to search for SNPs, and the function of the SNPs was examined by a set of biochemical assays. Genotypes and haplotypes were analyzed in 1026 patients and 1270 controls, and odds ratios and 95% confidence intervals (CIs) were estimated by logistic regression. RESULTS: Three SNPs, -1290A-->G, -1195G-->A, and -765G-->C, were identified; the frequencies of variant alleles were 0.04, 0.51, and 0.02, respectively. The -1195G-->A change creates a c-MYB binding site and displays a higher promoter activity. The -1195A-containing haplotypes had significantly increased luciferase expression and COX-2 messenger RNA levels in esophageal tissues compared with the -1195G-containing counterparts. A case-control analysis showed a 1.72-fold (95% CI, 1.35-2.20) and 2.24-fold (95% CI, 1.59-3.16) excess risk of developing ESCC for the -1195AA or -765CC genotype carriers compared with noncarriers. A greater risk of developing ESCC was observed for A(-1195)-C(-765)-containing haplotypes compared with G(-1195)-G(-765)-containing haplotypes, suggesting an interaction between the -1195G-->A and -765G-->C polymorphisms in the context of haplotype. CONCLUSIONS: These findings indicate that genetic variants in COX-2 may play a role in mediating susceptibility to esophageal cancer.

Adult↗

PubMed2005

Molecular cloning, expression, and purification of SARS-CoV nsp13.

The SARS-nsp13 protein was identified as an mRNA cap1 methyltransferase. In this study, the nsp13 gene was cloned from the SARS-CoV PUMC02 strain viral RNA by RT-PCR, and inserted into the expression plasmid pET30a(+). The recombinant plasmid pET30a(+)-nsp13 was confirmed by restriction enzymes and sequencing analysis, and transformed into Escherichia coli BL21(DE3). The His-tag-fused protein was expressed by induction of 0.5mM IPTG and purified by a single Ni(2+) affinity chromatography. The protein was validated by western blot and MS analysis. A large quantity of the nsp13 protein obtained with this method may be useful for further study of its structure and function.

Amino Acid Sequence↗

PubMed2004

-717A>G polymorphism of human C-reactive protein gene associated with coronary heart disease in ethnic Han Chinese: the Beijing atherosclerosis study.

Serum C-reactive protein (CRP) has been strongly implicated in the pathogenesis of coronary heart disease (CHD). We report here on the association between gene coding for CRP and CHD in the ethnic Han population of China. For this purpose two polymorphisms of -717A>G and +2147A>G of the CRP gene were identified by direct sequencing of genomic DNA derived from 48 randomly selected patients and these were further investigated for associations with CHD in 619 male patients and 615 age-matched male normal controls. The frequency of A allele carriers of -717A>G polymorphism was significantly higher in patients than in controls by univariate analysis. After controlling for other risk factors the association between this polymorphism and CHD remained significant by multivariate logistic regression analysis. Individuals carrying the -717A allele had an approx. 6.8-fold higher risk of developing CHD (odds ratio 6.84 compared with those not carrying this allele). Haplotype analysis confirmed the results of individual polymorphism analyses. However, the resolution of effect size is poor, which may be due to the deficiency in sample size of this study. Neither polymorphism was observed to have an influence on serum CRP level. Since the frequency difference between CHD cases and controls for the -717A allele carriers is only 2.28%, and homozygosity for -717G occurs in only 1.78% of subjects, -717 A>G polymorphism is not a major determinant of population genetic risk of CHD in the Chinese population. The association of this polymorphism with CHD supports the belief that carriers of -717A allele of the CRP gene are genetically predisposed to CHD in the Chinese Han population, and it remains possible that this polymorphism is in disequilibrium with one as yet unidentified functional polymorphism in the vicinity.

C-Reactive Protein↗