Biomedical subjects

Chunyan Wang

Publications and source records attributed to Chunyan Wang.

16 recordsLinked to original sources

PubMed2026

Cis-regulatory variation in the MdCKX6 promoter is associated with allele-specific expression and fruit size in apple.

Fruit size is a key determinant of apple fruit quality and market value and is strongly influenced by phytohormone-regulated cell proliferation and expansion during early fruit development. Cytokinin oxidase/dehydrogenase (CKX) enzymes regulate cytokinin homeostasis by irreversibly degrading active cytokinins, but the contribution of natural variation in CKX genes to fruit size remains poorly understood. Here, we identified MdCKX6 as a candidate regulator of fruit growth in apple (Malus domestica). MdCKX6 exhibited pronounced allele-specific expression during fruit development in the cultivar 'Royal Gala'. Sequence analysis identified a promoter SNP associated with differential promoter activity and allele-specific expression. Genotyping of diverse apple cultivars and wild Malus accessions revealed a significant association between MdCKX6 promoter genotype and fruit size. Cultivars carrying low-expression alleles produced larger fruits, whereas high-expression alleles were associated with smaller fruits. To investigate gene function, MdCKX6 was overexpressed in tomato, resulting in reduced fruit size. Histological analyses of the transgenic tomato fruit revealed smaller pericarp cells. Transcriptome analysis of transgenic fruits revealed widespread changes in genes associated with cell-cycle regulation, cell wall modification, hormone-related processes, and transcriptional regulation. Together, these results identify MdCKX6 as a potential negative regulator of apple fruit growth and reveal an association between cis-regulatory variants, gene expression, and fruit size. This study provides new insights into the role of cytokinin metabolism in fruit development and highlights regulatory variation in MdCKX6 as a potential target for apple breeding.

Malus↗

PubMed2025

Trio exome sequencing identifies de novo variants in novel candidate genes in 19.62% of CAKUT families.

PURPOSE: Congenital anomalies of the kidney and urinary tract (CAKUT) encompass heterogenous malformations arising from defective nephrogenesis. To date, approximately 50 monogenic genes are known to cause CAKUT if mutated. Recent studies show the impact of de novo variants in genetic disease etiology. Trio exome sequencing identifies de novo variants in novel candidate genes in 19.62% of CAKUT families. METHODS: We performed trio-based exome sequencing in 209 families with CAKUT to detect novel candidate disease genes. RESULTS: Trio analysis yielded in the identification of CAKUT candidate genes in 96 of 209 trio families (45.93%). In 41 of 209 cases, we detected strong de novo variants in 45 potential novel CAKUT candidate genes (19.62%). We developed a prioritization approach that highlights a truncating de novo variant in SOX13 (HGNC:11192) as a promising cause for CAKUT. In addition, further allele carriers for the candidate gene CHD1L (HGNC:1916) were identified, thus supporting the role of CHD1L in the pathogenesis of CAKUT. CONCLUSION: We conclude that de novo variants in potential novel CAKUT candidate genes contribute to the disease etiology and present SOX13 as a potential novel cause for CAKUT.

Humans↗

PubMed2007

Mesoporous nanotubes of iron phosphate: synthesis, characterization, and catalytic property.

Iron phosphate nanotubes with mesoporous walls are solvothermally synthesized using sodium dodecyl sulfate (SDS) as a template. With different template concentrations, various shapes of nanosized iron phosphates can be obtained. When the concentration of SDS is set at the transition regions between the lamellar and the hexagonal mesophases, according to its phase diagram, the coassembly of iron phosphate precursor and SDS forms a flake-type mesoporous iron phosphate. Otherwise, nanoparticles or bulky sheets of iron phosphates are obtained. The followed solvothermal treatments on the mesoporous iron phosphate flakes produce iron phosphate nanotubes with mesoporous walls. The removal of the surfactant by acetate exchange and heat treatment results in the clean mesoporous nanotubes of iron phosphate with diameters of 50-400 nm and lengths of several microns. The nanotubular and mesoporous iron phosphate possesses a specific surface area of 232 m2/g and a bimodal distribution of pore sizes, corresponding to the size of mesopores in the walls and the diameter of the nanotubes, respectively. The novel nanotubular iron phosphate with composite meso-macroporous structure, in favor of the diffusion of reactive molecules, has been tested for direct hydroxylation of benzene with hydrogen peroxide and has shown better catalytic performance compared with the conventional particulate mesoporous iron phosphate.

Journal Article↗

PubMed2006

Role of an extracellular neutral protease in infection against nematodes by Brevibacillus laterosporus strain G4.

Proteases have been proposed as virulence factors in microbial pathogenicity against nematodes. However, what kinds of extracellular proteases from these pathogens and how they contribute to the pathogenesis of infections against nematode in vivo remain largely unknown. A previous analysis using a strain with a deletion in an extracellular alkaline protease BLG4 gene from Brevibacillus laterosporus demonstrated that BLG4 was responsible for the majority of nematicidal activity by destroying host's cuticle. In recent studies, a neutral protease NPE-4, purified from the mutant BLG4-6, was found to be responsible for the majority of the remaining EDTA-inhibited protease activity. However, the purified NPE-4 and recombinant NPE-4 in a related species Bacillus subtilis showed little nematicidal activity in vitro and were unable to degrade the intact cuticle of the host. It is interesting to note that the addition of NPE-4 improved the pathogenicity of crude enzyme extract from wild-type B. laterosporus but had no effect on the BLG4-deficient mutant. This result suggests that NPE-4 functions in the presence of protease BLG4. Moreover, NPE-4 could degrade proteins from the inner layer of purified cuticles from nematode Panagrellus redivivus in vitro. These results indicated that the two different bacterial extracellular proteases might play differential roles at different stages of infection or a synthetic role in penetration of nematode cuticle in B. laterosporus. This is among the first reports to systematically evaluate and define the roles of different bacterial extracellular proteases in infection against nematodes.

Amino Acid Sequence↗

PubMed2006

Molecular cloning and characterization of human Aph2 gene, involved in AP-1 regulation by interaction with JAB1.

A human Aph2 gene (hAph2) was identified and cloned from a human placenta cDNA library. Bioinformatics analysis revealed hAPH2 protein shares 96% identity with mouse APH2 and contains a zf-DHHC domain (148-210aa), which is always involved in protein-protein or protein-DNA interaction. Differential expression patterns of hAph2 mRNA were observed in normal human tissues. Yeast two-hybrid screening found another hAPH2-interacting protein JAB1. The zf-DHHC domain of hAPH2 and the C-terminal of JAB1 were confirmed to be critical for the interaction. Fused with GFP and expressed in COS-7, NIH/3T3 and SMMC-7721 cell lines, hAPH2 showed predominant distribution in the cytoplasm and co-localized with JAB1 around the nucleus. Furthermore, overexpression of hAPH2 could increase apoptosis of COS-7 cells and negatively regulate JAB1-induced activation of AP-1 in a concentration dependent manner. The expression level of c-jun was also down-regulated by overexpression of hAPH2 in COS-7 cells. These data showed some basic characterization and function of hAph2 (hAPH2), dependent or independent with JAB1.

Amino Acid Sequence↗

PubMed2006

The complete genome sequence of a chronic atrophic gastritis Helicobacter pylori strain: evolution during disease progression.

Helicobacter pylori produces acute superficial gastritis in nearly all of its human hosts. However, a subset of individuals develops chronic atrophic gastritis (ChAG), a condition characterized in part by diminished numbers of acid-producing parietal cells and increased risk for development of gastric adenocarcinoma. Previously, we used a gnotobiotic transgenic mouse model with an engineered ablation of parietal cells to show that loss of parietal cells provides an opportunity for a H. pylori isolate from a patient with ChAG (HPAG1) to bind to, enter, and persist within gastric stem cells. This finding raises the question of how ChAG influences H. pylori genome evolution, physiology, and tumorigenesis. Here we describe the 1,596,366-bp HPAG1 genome. Custom HPAG1 Affymetrix GeneChips, representing 99.6% of its predicted ORFs, were used for whole-genome genotyping of additional H. pylori ChAG isolates obtained from Swedish patients enrolled in a case-control study of gastric cancer, as well as ChAG- and cancer-associated isolates from an individual who progressed from ChAG to gastric adenocarcinoma. The results reveal a shared gene signature among ChAG strains, as well as genes that may have been lost or gained during progression to adenocarcinoma. Whole-genome transcriptional profiling of HPAG1's response to acid during in vitro growth indicates that genes encoding components of metal uptake and utilization pathways, outer membrane proteins, and virulence factors are among those associated with H. pylori's adaptation to ChAG.

Adenocarcinoma↗

PubMed2006

Preparation and identification of anti-2, 4-dinitrophenyl monoclonal antibodies.

2, 4-Dinitrophenyl (DNP) is a widely used hapten in molecular biology and immunoassay fields. Considering that 2, 4-dintrophenylhydrazine (DNPH) could be used as DNA probe and bind with protein carbonyl to form a stable 2 4-dinitrophenyl (DNP) hydrazone product, on which the level of oxidative stress could be validated with a sensitive noncompetitive ELISA, we prepared DNP-aminocaproic acid and NHS-aminocaproic acid-dinitrobenzene and the conjugates between DNP and carrier proteins such as bovine thyroglobulin (BTG) and bovine serum albumin (BSA). High titer antibody producing spleen cells were removed and fused with myeloma cells of SP2/0 origin. Using a conventional immunization protocol, twenty stable murine monoclonal antibodies (MAbs) producing cell lines to DNP were generated. The donor mouse produced antiserum with a high titer of 1/1,280,000. Five MAbs were selected for further characterization as class and subclass. After four successive limiting dilutions, antibodies were produced by five clones with high affinities ranging from 10(10) to 10(11) M(-1). These clones were found to be of IgG(1) subclass with kappa and lambda light chain. Competitive ELISA and SPR-based sensing system for the detection of DNPH are both used to confirm the specificity of MAb (4D(9)A(9)C(2)C(2)).

2,4-Dinitrophenol↗

PubMed2006

Antisense telomerase RNA inhibits the growth of human glioma cells in vitro and in vivo.

Telomerase is implicated in the development of cellular immortality and oncogenesis. It has been shown that telomerase activity is considerably higher in the tissue of many different cancers than in normal tissue, and that the inhibition or downregulation of telomerase activity can prevent the malignant proliferation of tumor cells. Antisense oligonucleotides have been widely used in suppressing the expression of genes and, therefore, in the present research, we evaluated the effect of antisense human telomerase RNA (hTR) on glioma cell growth in vitro and in vivo. We showed that antisense hTR cDNA significantly inhibited TJ905 human glioma cell proliferation in vitro and tumor growth in vivo, as determined by MTT assay and by measuring the volume of glioma in nude mice. Consistent with these results, we found that telomerase activity and the mRNA levels of hTR and hTERT (human telomerase reverse transcriptase) expression were markedly decreased in tumor cells treated with antisense hTR cDNA, as assessed by TRAP (telomeric repeat amplification protocol) assay and RT-PCR (reverse transcription-polymerase chain reaction) analysis. Our study conclusively demonstrates that antisense hTR effectively inhibits the growth of human glioma cells in vitro and in vivo and, thus, may be potentially used for gene therapy of malignant gliomas and other cancers.

Actins↗

PubMed2006

[Coblation tonsillectomy versus blunt dissection tonsillectomy].

OBJECTIVE: Compare coblation tonsillectomy with blunt dissection tonsillectomy to see if there is any difference in intraoperative bleeding, operating time, postoperative pain, tonsillar fossae healing and return to normal diet and activities. METHOD: A randomised control trial was carried out to compare coblation tonsillectomy with blunt dissection tonsillectomy in 56 patients. The same surgeon operated on them all, using Arthro Care EVac 70 Wand for coblation tonsillectomy, and routine instruments for blunt dissection tonsillectomy. RESULT: Coblation tonsillectomy was fast and resulted in little intraoperative bleeding. Significant reduction in postoperative pain was found in the patients with coblation tonsillectomy. Patients who had coblation tonsillectomy returned to their normal diet sooner than those who underwent blunt dissection tonsillectomy. Slower healing of the tonsillar fossae was found in the coblation group. One patient in the coblation group suffered from secondary haemorrhage. CONCLUSION: Coblation tonsillectomy is easy to perform with little intraoperative bleeding. It offers significant advantages in the postoperative period, with rapid return to a normal diet and reduction in postoperative pain. But it need more time for healing of the tonsillar fossae.

Adolescent↗

PubMed2005

A new human gene hNTKL-BP1 interacts with hPirh2.

NTKL (N-terminal kinase-like protein) encodes an evolutionarily conserved kinase-like protein and is mapped around chromosomal breakpoints found in several carcinomas, suggesting that NTKL dysfunction may be involved in carcinogenesis. Recently, we identified a novel mouse gene, mNTKL-BP1 (NTKL-binding protein 1), encoding a protein interacting with NTKL. For further study, a new human gene, hNTKL-BP1, which is highly homologous with mNTKL-BP1, was used as bait in yeast two-hybrid system. hPirh2 (human p53-induced RING-H2 protein) was identified as hNTKL-BP1 interacting protein. The specific interaction of two proteins was confirmed by pull-down assay in vitro and co-immunoprecipitation in vivo. Moreover, an immunofluorescent staining assay showed that hNTKL-BP1 colocalizes with hPirh2 in SMMC 7721 cells. It will stimulate further investigation into whether hNTKL-BP1 is the substrate of hPirh2 or interaction of hNTKL-BP1 with hPirh2 enhances or represses the ubiquitin-protein ligase activity of hPirh2.

Amino Acid Sequence↗

PubMed2005

Generation and annotation of the DNA sequences of human chromosomes 2 and 4.

Human chromosome 2 is unique to the human lineage in being the product of a head-to-head fusion of two intermediate-sized ancestral chromosomes. Chromosome 4 has received attention primarily related to the search for the Huntington's disease gene, but also for genes associated with Wolf-Hirschhorn syndrome, polycystic kidney disease and a form of muscular dystrophy. Here we present approximately 237 million base pairs of sequence for chromosome 2, and 186 million base pairs for chromosome 4, representing more than 99.6% of their euchromatic sequences. Our initial analyses have identified 1,346 protein-coding genes and 1,239 pseudogenes on chromosome 2, and 796 protein-coding genes and 778 pseudogenes on chromosome 4. Extensive analyses confirm the underlying construction of the sequence, and expand our understanding of the structure and evolution of mammalian chromosomes, including gene deserts, segmental duplications and highly variant regions.

Animals↗

PubMed2004

Comparison of genome degradation in Paratyphi A and Typhi, human-restricted serovars of Salmonella enterica that cause typhoid.

Salmonella enterica serovars often have a broad host range, and some cause both gastrointestinal and systemic disease. But the serovars Paratyphi A and Typhi are restricted to humans and cause only systemic disease. It has been estimated that Typhi arose in the last few thousand years. The sequence and microarray analysis of the Paratyphi A genome indicates that it is similar to the Typhi genome but suggests that it has a more recent evolutionary origin. Both genomes have independently accumulated many pseudogenes among their approximately 4,400 protein coding sequences: 173 in Paratyphi A and approximately 210 in Typhi. The recent convergence of these two similar genomes on a similar phenotype is subtly reflected in their genotypes: only 30 genes are degraded in both serovars. Nevertheless, these 30 genes include three known to be important in gastroenteritis, which does not occur in these serovars, and four for Salmonella-translocated effectors, which are normally secreted into host cells to subvert host functions. Loss of function also occurs by mutation in different genes in the same pathway (e.g., in chemotaxis and in the production of fimbriae).

Base Sequence↗

PubMed2004

Effect of smoking on chromosomes compared with that of radiation in the residents of a high-background radiation area in China.

Cytogenetic investigation of stable-type aberrations (translocations) was carried out with our improved methods on 28 elderly individuals in a high-background radiation area (HBRA) in China, and on 24 elderly individuals in a control area (CA). The level of radiation in HBRA is 3 to 5 times higher than in CA. The mean frequencies of translocations per 1,000 cells in HBRA and CA were 12.4 +/- 5.3 and 10.0 +/- 3.8, respectively. No significant difference was found in the frequencies between HBRA and CA (P>0.05, Mann-Whitney U test). When elderly individuals in HBRA and CA were classified into four subgroups of HBRA nonsmokers, HBRA smokers, CA nonsmokers, and CA smokers, a significant difference was found in the frequencies between CA smokers and CA nonsmokers (P<0.05, Mann-Whitney U test). Furthermore a tendency of difference (a near T-value of 0.05 level) was found in a comparison of HBRA smokers vs. CA nonsmokers. The present results indicate that the elevated level of natural radiation in HBRA plays a less significant part than smoking in bringing about the induction rate of stable-type aberrations (translocations) in those areas.

Aged↗

PubMed2003

Imperceptible effect of radiation based on stable type chromosome aberrations accumulated in the lymphocytes of residents in the high background radiation area in China.

Cytogenetic investigation of stable type aberrations (translocations) was performed with our improved methods in 6 children and 15 elderly persons in a high background radiation area (HBRA) in China, and in 8 children and 11 elderly persons in a control area. The total numbers of cells analyzed in elderly persons were 68,297 in HBRA and 35,378 in controls and in children were 45,535 in HBRA and 56,198 in controls. On average 5138 cells per subject were analyzed. The variation in the frequencies of translocations per 1000 cells was small in children while it was large in elderly persons. No significant difference was found in the frequencies between HBRA and control (P > 0.05, Mann-Whitney U test). On the other hand, correlation between age and translocation frequencies was significant at the 1% level (rs = 0.658 with 37DF, Spearman rank correlation test). The contribution of an elevated level of natural radiation in HBRA in China to the induction of stable type chromosome aberrations does not have a significant effect compared with the contribution of chemical mutagens and/or metabolic factors. The present study suggests that the probability of the risk of causing malignant and/or congenital diseases by the increased amount of radiation is imperceptible in HBRA where the level of natural radiation is 3 to 5 times higher than that in the control area.

Aged↗

PubMed2002

[Telomerase activity and regulation in human neuroepithelial tumors].

OBJECTIVE: To investigate telomerase activity and expression of hTR and hTERT in human neuroepithelial tumors for exploring new strategy for clinical diagnosis and treatment. METHODS: Telomerase activity was detected by modified TRAP method and the expression of hTR and hTERT was measured by RT-PCR method in 65 human neuroepithelial tumors, respectively. RESULTS: The positive rates of telomerase and hTERT were 61.54% and 70.77% respectively in human neuroepithelial tumors, and the positive rate and their level of expression were correlated with the degree of malignancy of tumors positively. CONCLUSIONS: Telomerase activity and hTERT are significantly correlated with the degree of malignancyin human neuroepithelial tumors. hTERT may play a key role in the regulation of telomerase activity.

DNA-Binding Proteins↗

PubMed2002

[Preliminary study on the gene expression profiles of oligodendrogliom as with cDNA array].

OBJECTIVE: To study the gene expression profiles of oligodendrogliomas with gene cDNA array. METHODS: (32)P tagged cDNA probes converted from the total RNA, which had been extracted from 2 fresh samples of oligodendroglioma and 1 of normal brain tissue, were hybridized with the Atlas array. After washing the membranes, the autoradiography was performed and the autoradiograms were analyzed through the special software. RESULTS: As compared to the normal brain tissue, there were 63 co-upregulated genes and 4 co-downregulated genes in these 2 tumor samples. However, a significant quantitative difference existed between them. The expression trend of some genes differed from the known information. CONCLUSION: cDNA array is effective for studying the gene expression profiles of oligodendrogliomas and provides new information for the further research on their molecular mechanisms.

Brain Neoplasms↗