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Biomedical subjects

Bo Zhang

Publications and source records attributed to Bo Zhang.

At least 199 records · Page 11Linked to original sources
PubMed2004

[The molecular interaction between P53 and telomeric repeat binding protein 1 in vitro].

OBJECTIVE: Cellular proliferate inhibition, senescence or apoptosis are induced by telomere shortening through the activation of P53 pathway, but so far, little is known of the mechanism. This study aimed to clarify the molecular regulation of P53 through telomere pathway by the investigation of molecular interaction between P53 and the main telomere associated protein telomeric repeat binding protein 1(TRBP1) in vitro. METHODS: Glutathione S-transferase (GST) alone and 4 different human P53-GST fusion proteins were expressed in E.coli. and purified through glutathione Sepharose (TM)4B by affinity chromatography, P53s were wild type P53 (1-393), N terminal truncated form P53 2C (95-393), C terminal truncated form P53 N5 (2-293) and single amino acid mutant P53 R175H (175 arginine to histidine). Glutathione Sepharose (TM)4B, purified GST alone and P53 fusions were mixed with human breast cancer cell line MCF-7 cellular protein extracts through in vitro binding assay-pull down, the molecular interaction between P53 and TRBP1 were detected by Western blot. RESULTS: SDS-PAGE and Coomassie brilliant blue staining showed that the molecular weights of all the purified proteins were as expected and purities were over 90%. Western blot of TRBP1 showed that both wild type P53 and P53 R175H could bind to TRBP1 of MCF-7 cells, and their binding capacities are similar, whereas GST alone and Glutathione Sepharose(TM) 4B beads could not. Compared with both of them, the interaction between P53 2C and TRBP1 enhanced dramatically, but between P53 N5 and TRBP1 reduced significantly. CONCLUSION: P53 can interact with TRBP1 directly and in vitro, C terminus of P53 (293-393) is the structural domain of their interaction. This C terminus domain dependent interaction between P53 and TRBP1 may be related to the cellular activities induced by telomere dynamic changing.

Adenocarcinoma↗
PubMed2004

[Molecular characterization of mutations and phenotype/genotype correlation in Chinese patients with 21-hydroxylase deficiency].

To investigate characteristics of CYP21 mutations in Chinese patients with 21-hydroxylase deficiency (21-OHD) and the relationship between genotype and phenotype, a time saving, reliable molecular diagnosis method was developed. Eight patients with NC 21-OHD, 35 patients with classical ones and 34 normal controls were studied as followed: CYP21 gene was amplified into fragment 1 (exon1 --> exon3) and fragment 2 (exon3 --> exon10) through PCR with specific primers. The second round PCR was carried out using fragment 1 and 2 as template, and PCR products were digested by restrictive enzymes to analyze nine mutations, including Del, Exon3 Del8 bp, Q318X, R356W, Exon6Cluster, i2g, l172N, P30L and V281L. The most frequent mutation in 43 cases of Chinese 21-OHD was l172N (36.0%), followed by i2g (20.9%), Del (8.6%), P30L (7.0%), Q318X (7.0%), V281L (4.7%), R356W (2.3%), E6Cluster (2.3%) and Exon3 Del8 bp (1.2%). The most common CYP21 gene defect in salt wasting, simple virilizing and nonclassical form was Del (44.4%), l172N (44.2%) and P30L (37.5%) respectively. In addition, genotype was classified into three (severe, moderate and mild) groups according to the degree of 21-hydroxylase enzymatic compromise caused by the mutation. Age of first visit, basal 17-OHP, composition of disease subtype were significantly different among the three groups, P < 0.05. In conclusion, the most common mutations in Chinese 21-OHD were l172N, i2g and Del. The genotype of Chinese 21-OHD has strong correlation with the phenotype.

Adolescent↗
PubMed2004

[Expression of pRb and E2F-1 and telomerase activity in ameloblastoma].

OBJECTIVE: To investigate the expression of pRb and E2F-1, and the association between their expression and the activity of telomerase (hTERT) or cyclin E in human ameloblastoma (AB), and to explore the clinical biological characteristics of AB. METHODS: The expressions of pRb, E2F-1, cyclin E and hTERT mRNA in human AB were detected by in situ hybridization or immunohistochemistry (SP method). RESULTS: The positive expression ratio of pRb in the cell nucleus of AB was 20.4% (11/54). The positive ratio of E2F-1, cyclin E and hTERT mRNA was 92.6% (50/54), 66.7% (36/54) and 94.4% (51/54), respectively. With AB recurrence and malignant transformation, the expression of hTERT, E2F-1, cyclin E was up-regulated. hTERT and cyclin E or E2F-1 mRNA had high positive relation (Spearsman'r(s) = 1.000, P = 0.0001). CONCLUSIONS: The regulatory pathway of Rb/E2F-1 is associated with the cell proliferation and in differentiation of AB. The activity or release of telomerase may be related to the lower expression of Rb and higher expression of E2F-1, and is up-regulated in G(1) late phase by cyclin E.

Adolescent↗
PubMed2004

Inhibitory role of transcription factor COUP-TFII in expression of hTERT in HeLa cells.

OBJECTIVE: To clone and identify the proteins involved in regulating the transcription of hTERT and study the role of genes in both hTERT transcription and telomerase activity. METHODS: The full cDNA of COUP-TFII was cloned from HeLa cDNA library by hTERT promoter-based yeast one-hybrid assay and then in-frame inserted into His-tag fusion expression vector pEK318. The His-tag COUP-TFII fusion proteins were purified by Ni-NTA chromatography. The interaction of COUP-TFII with hTERT promoter in vitro was identified by electrophoretic mobility shift assay and Footprint. The role of COUP-TFII in both hTERT transcription and telomerase activity were probed through Luciferase reporter assay, Northern blot, and TRAP-PCR ELISA. RESULTS: COUP-TFII could firmly bind to the downstream E-box and the other two binding sites in hTERT promoter. Luciferase reporter assay indicated COUP-TFII could suppress hTERT promoter activity and stable introduction of COUP-TFII into HeLa cells also decreased both endogenous hTERT transcription and telomerase activity. CONCLUSION: The human COUP-TFII can firmly bind to hTERT promoter, and inhibit telomerase activity through decreasing hTERT transcription. It will greatly facilitate understanding of telomerase regulation in normal and cancer cells.

COUP Transcription Factor II↗
PubMed2004

[Prediction of the spatial distribution of Oncomelania snails in marshland of Jiangning County using the Ordinary Kriging].

OBJECTIVE: To explore the methods to predict the distribution of Oncomelania hupensis in the marshland of Jiangning County. METHODS: Semi-variogram was used to analyze the spatial autocorrelation of snails' distribution in the marshland of Jiangning using the Arcview8.1. A prediction map for the snails' distribution was established using the Ordinary Kriging and evaluated using the cross-validation. RESULTS: Analysis showed that the distribution of alive snails in the marshland of Jiangning in the year 2000 was auto-correlated in spatial. The semi-variogram model which was spherical demonstrated that the variation of alive snails in spatial were related with distance apart when the distance was less than 0.0301. The prediction map of the snail distribution in the marshland of Jiangning was established based on the semi-variogram using the Ordinary Kriging. The cross-validation showed that the prediction map could estimate the distribution of snails in the marshland of Jiangning correctly. And the determinant coefficient for the prediction model was 0.973. CONCLUSION: It is feasible to predict the snail distribution in the marshland of Jiangning County by using Ordinary Kringing and data from the surveillance spot.

Animals↗
PubMed2004

[Research on the expression of c-myc mRNA in ameloblastoma].

PURPOSE: To study the expression of c-myc mRNA in ameloblastoma (AB) and odontogenic keratocyst (OKC) and to investigate the genesis, development and biological characteristics of AB and OKC. METHODS: We detected c-myc mRNA in 54 cases of AB (31 primary ABs, 19 recurrent Abs and 4 malignant ABs), 16 cases of OKC and 7 cases of normal oral mucosa (NOM) by in situ hybridization. Chi2 test was used to analyze the results. RESULTS: The positive rate of AB, OKC and NOM was 81.5% (44/54), 75.0% (12/16) and 14.3% (1/7), respectively. There was statistical difference among three groups (chi2=15.488, P<0.05). Comparing the expression of primary AB (71.0%) with recurrent (94.7%), malignant AB (100.0%), there was a significant statistical difference (chi2=16.912, P<0.05). CONCLUSIONS: The expression of c-myc is important to the genesis and development of AB; following the change of primary, recurrent and malignant AB, the expression of c-myc mRNA increased significantly.It is suggested that c-myc mRNA may be an effective marker to evaluate the prognosis of AB.

Ameloblastoma↗
PubMed2004

[The progress in the study of chromatin insulator].

Chromatin insulators, which define domains of transcriptional autonomy, are cis-acting elements of eukaryotes. They are located at the boundaries of differentially regulated genes and delimit their interactions by establishing independent chromatin structures. They can block chromosomal enhancers or silencers if they are located between promoters and enhancers or silencers, and protect against position effect. Recent studies focus on elucidating the molecular mechanism of insulator functions. Loop Model is the most predominant hypothesis while others are assumed. Study progress in this field sheds new light on the regulation of gene expression.

Animals↗
PubMed2004

[Research of bone bridge-like on plasma sprayed HA coating].

Bone formation on hydroxyapatite (HA) coating in the presence of gaps is important for clinical application. Pure Ti and hydroxyapatite coated by plasma sprayed samples were implanted in dog respectively. The implants were surrounded by gaps of 2 mm, and the follow-up period was 12 weeks. Histological examination and histomorphometry revealed that gaps could be bridged by bone provided the hydroxyapatite coating was applied, and that pure Ti implants were surrounded by fibrous tissue with no bone contact at all.

Animals↗
PubMed2004

[Expression of telomerase activity and c-myc and stimulatory protein 1 in human ameloblastoma].

OBJECTIVE: To study the oncogene transcriptor c-myc, stimulatory protein 1 (SP1) expression in ameloblastoma (AB) and their relation with telomerase reverse transcripase (hTERT), and to investigate the clinical biological characteristics of AB. METHODS: The expression was observed in AB by in situ hybridization and SP method. RESULTS: The positive rates of c-myc mRNA, hTERT mRNA and SP1 protein were 81.5% (44/54), 94.4% (51/54) and 83.3% (45/54), respectively. Their positive rates increased as AB recurred and transformed malignantly. A strong correlation was found between hTERT and c-myc, hTERT and SP1 (rs = 0.853, P < 0.001; rs = 0.900, P < 0.001). CONCLUSION: Activity of telomerase plays an important role in the tumorigenesis development of AB. Increasing of hTERT expression may be related to c-myc and SP1. The expression of these three parameters has a significant correlation with the clinical biological characteristics of AB.

Ameloblastoma↗
PubMed2003

Pore exclusion chromatography-inductively coupled plasma-mass spectrometry for monitoring elements in bacteria: a study on microbial removal of uranium from aqueous solution.

The interstitial spaces between spherical particles in a packed column can act as a sieve that passes microorganisms below a certain size. If the bed is a perfusion-type material (containing a binary distribution of large and small pores), colloidal-size microorganisms are subject only to pore exclusion, while all molecules are subject to size exclusion among the various pores. Thus, microorganisms elute first, followed by macromolecules, and then small molecules. Coupling this separation method to an ICP magnetic sector mass spectrometer provides a sensitive, direct means to study the microbial uptake of heavy metals (i.e., uranium) from their surrounding environments. Multiple metal ions can be monitored in the microorganism and in the surrounding solution. In this way, definitive information can be provided for the remediation of radioactive waste sites. The effect of uranium on microbial growth is also discussed.

Bacillus subtilis↗
PubMed2003

[Proliferation and differentiation of neural stem cells after cerebral infarction: an experimental study of adult rats].

OBJECTIVE: To investigate the proliferation and differentiation of neural stem cells after cerebral infarction(CI) in adult rats. METHODS: CI animal model was made by ligating the common carotid artery and external carotid artery and inserting a piece of nylon thread into the internal carotid artery among 100 male Wistar rats. Then the rats were randomly divided into 5 groups: group of I day after brain infarction (n = 20), group of 3 days after brain infarction (n = 20), group of 7 days after brain infarction (n = 20), group of 14 days after brain infarction (n = 20), and group of 28 days after brain infarction (n = 20). Twelve rats undergoing sham operation with a piece of nylon thread inserted only into the common carotid artery were used as controls. The rats were killed at different time points and their brains were taken out. The expression of bromodeoxyuridine (BrdU) and Musashil (both used to mark the dividing neural stem cells), and of glial fibrillary acidic protein (GFAP) and neuronal nuclear antigen (NeuN) (both used to mark the differentiating neural stem cells) were determined by immunohistochemistry and immunofluorescence staining. RESULTS: In the normal brain tissues, only a small amount of BrdU(+) cells were found in the hippocampus. One day after CI the number of BrdU(+) cells began to increase in the hippocampus at the CI side (P < 0.05), peaked 7 days after CI with a number 6 times that at the normal side, began to decrease 14 days after, and almost reached normal 28 days after. The number of BrdU(+)/Musashil(+) cells began to increase 1 day after CI (P < 0.05), peaked 7 days after, began to decrease 14 days after, and almost reached normal 28 days after. The number of BrdU(+)/GFAP(+) cells at the CI side remained almost unchanged after CI. The number of BrdU(+)/NeuN(+) cells began to increase 14 days after CI (P < 0.05) and peaked 38 days after. CONCLUSION: Cerebral infarction stimulates the proliferation of inherent neural stem cells and most proliferated neural stem cells differentiate into neurons.

Animals↗
PubMed2003

Molecular cloning of a novel human gene encoding histone acetyltransferase-like protein involved in transcriptional activation of hTERT.

To isolate proteins involved in hTERT transcriptional regulation, the HeLa cDNA library was screened using the hTERT promoter-based yeast one-hybrid assay. A positive clone was rescued and proved to contain an open reading frame and the upstream coding sequences were obtained by 5'-RACE. The assembled full cDNA consisted of a 2.5 kb reading frame encoding 834 amino acids, in which a conserved N-acetyltransferase domain (GNAT family) was searched out in bioinformatics, and thus named as hALP (human N-acetyltransferase-like protein, GenBank Accession No. AF 489535). The expression of native hALP was identified in HeLa cells and proved to distribute in the cellular nucleus. The binding potential of hALP to hTERT promoter was confirmed by EMSA and the interacting sequence involved to -201- to -56-nt upstream region of the promoter. On transfection assay, hALP could obviously transactivate hTERT promoter and stimulate endogenous telomerase activity of cells. The analysis on histone acetyltransferase showed that hALP could specifically acetylate free histones in vitro. The investigation suggested that hALP influences the activity of histone acetylation and could up-regulate telomerase activity through transactivation of hTERT promoter.

Amino Acid Sequence↗
PubMed2003

A novel cysteine cluster in human metal-responsive transcription factor 1 is required for heavy metal-induced transcriptional activation in vivo.

Metal-responsive transcription factor 1 (MTF-1) specifically binds to metal response elements (MREs) associated with a number of metal- and stress-responsive genes. Human MTF-1 contains a cysteine-rich cluster, -632Cys-Gln-Cys-Gln-Cys-Ala-Cys638-, conserved from pufferfish to humans far removed from the MRE-binding zinc finger domain and just C-terminal to a previously mapped serine/threonine-rich transcriptional activation domain. MTF-1 proteins containing two Cys-->Ala substitutions (C632A/C634A) or a deletion in this region altogether (Delta(632-644)) are significantly impaired in their ability to induce Zn(II)- and Cd(II)-responsive transcription of a MRE-linked reporter gene in transiently transfected mouse dko7 (MTF-1-/-) cells in culture under moderate metal stress but retain the ability to drive basal levels of transcription in a MRE-dependent manner in vivo and in vitro. In addition, the mutated proteins respond to induction by Zn(II) or Cd(II) with nuclear translocation and MRE binding activities comparable with wild-type MTF-1. Attempts to rescue the Delta(632-644) deletion mutant phenotype by inserting similar Cys-rich sequences from Drosophila MTF-1 were unsuccessful, suggesting that the structure of this motif within intact human MTF-1, rather than the simple presence of multiple closely spaced Cys residues, is required for function. This cysteine cluster therefore functions at a step subsequent to nuclear translocation and MRE-binding DNA to naked promoter-containing DNA and appears to be specifically required for MTF-1 to activate transcription in the presence of inducing heavy metal ions.

Amino Acid Sequence↗
PubMed2003

Temporal and spatial expression of tissue inhibitors of metalloproteinases 1 and 2 (TIMP-1 and -2) in the bovine corpus luteum.

The matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs), may mediate the dramatic structural and functional changes in the corpus luteum (CL) over the course of its life span. In addition to regulating MMP activity, TIMPs are also involved in a variety of cellular processes, including cell proliferation and steroidogenesis. In a series of initial studies, we determined that matrix metalloproteinase inhibitory activity was present in protein extracts from early (4 days old, estrus = day 0), mid (10-12 days old) and late (16 days old) CL (n = 3 for each stage). Reverse zymography revealed four metalloproteinase inhibitory protein bands with relative molecular masses that are consistent with those reported for TIMP-1 to -4. In order to gain a better understanding of TIMPs and their role in luteal function, we further characterized this inhibitory activity with a particular focus on the temporal and spatial expression of TIMP-1 and TIMP-2 in the bovine CL. Northern blotting revealed that the TIMP-1 transcript (0.9 kb) was expressed at a higher (p < 0.05) level in early and mid cycle CL than in the late stage. In contrast, two TIMP-2 mRNA species, one major 1 kb species and one minor 3.5 kb species, were significantly (p < 0.05) increased in the mid and late cycle CL than in the early. Western blotting analyses demonstrated no differences in TIMP-1 (29 kDa) protein levels between early and mid stages, while its levels decreased (p < 0.05) from the mid to late stage CL. Conversely, TIMP-2 (22 kDa) protein was detected at a low level in the early CL, but significantly (p < 0.05) increased in the mid and late stages. Immunohistochemistry revealed that both TIMP-1 and -2 were localized to large luteal cells from all three ages of CL. TIMP-1 was also localized in capillary smooth muscle cells, while TIMP-2 was restricted to the endothelial cells in the capillary compartment. In conclusion, the different temporal expression patterns of TIMP-1 and TIMP-2 suggest that TIMP-1 may be important for luteal formation and development, while TIMP-2 may play significant roles during luteal development and maintenance. Furthermore, the distinct localization of these two inhibitors in the vascular compartment indicates that they may serve diverse physiological functions during different stages of luteal angiogenesis.

Animals↗
PubMed2003

Bound-bound state quantum wave packet dynamics in the intermediate coupling range: the A1Sigma+u (0+u) and b3IIu (0+u) system in Rb2.

The real-time quantum dynamics of a wave packet confined to two coupled bound states at intermediate interaction strength is probed by experiment and calculations on the A1Sigma(+)(u) approximately b (3)II(u) system in Rb2 molecules. The general dynamics consists of rapid spreading out over the whole phase space. Particular conditions exist, however, under which the initial wave packet motion separates into two mesobatic trajectories with distinct frequencies. These diabatic or adiabatic hybrid trajectories are analogous to those responsible for longevity resonances in bound-unbound systems.

Journal Article↗
PubMed2003

Efficient asymmetric synthesis of the vasopeptidase inhibitor BMS-189921.

[reaction: see text] An efficient asymmetric synthesis of the vasopeptidase inhibitor BMS-189921 was accomplished. Two short enantioselective syntheses of the common key intermediate (S)-alpha-aminoazepinone 6b were developed. Olefin 3 was converted to 6b via asymmetric hydrogenation. Alternatively, enyne 12 was converted to racemic alpha-aminoazepinone 15b, which was transformed to 6b by a practical dynamic resolution.

Azepines↗
PubMed2003

[Production and purification of helper free recombinant adeno-associated virus 2].

OBJECTIVE: To explore an efficient and simple way to product and purify helper free adeno-associated virus vectors. METHOD: Helper free rAAV system was transferred into HEK293T cells through phosphorated calcium method, thus producing rAAV, then the rAAV vector was purified through chloroform-PEG8000/NaCl-chloroform method and ultrafiltration. SDS-PAGE protein electrophoresis and Western blotting were used to detect the rAAV protein. The quantity of rAAV genome was determined through blot hybridization. HEK293T cells were cultured, rAAV was added, and fluorescence microscopy was used to count the amount of cells expressing green fluorescent protein so as to measure the transferring unit of rAAV. RESULTS: rAAV2 was thus produced with a particle number of 2 x 10(13)/ml and a transferring unit of 5 x 10(11)/ml. CONCLUSION: This method to produce and purify rAAV is efficient and simple, without need of any special equipment, and can be finished in a common laboratory.

DNA Primers↗