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Tao Chen

Publications and source records attributed to Tao Chen.

At least 55 records · Page 3Linked to original sources
PubMed2006

[The wild-type alpha-synuclein over-expression to induce the protein aberrant aggregation of alpha-synuclein in HEK293 cells in vitro].

OBJECTIVE: To investigate over-expression of wild-type alpha-synuclein inducing the aberrant aggregation of alpha-synuclein in HEK293 cell in vitro. METHODS: The cDNA encoding the human alpha-synuclein without the stop code was cloned into PGEM T-easy vector. Using enzyme map and DNA sequencing analyzed and determined the recombinant plasmid, and then sub-clone the alpha-synuclein cDNA fragment into pEGFP-N1 vector. The recombinant plasmids alpha-synuclein-pEGFP were transfected into HEK293 cells by lipofectamin 2000. The aberrant aggregation of alpha-synuclein was measured by EGFP fluorescence, anti-alpha-synuclein immunocytochemistry. The inclusions in the cultured cells were identified with HE staining. RESULTS: The restriction enzyme map suggested that eukaryotic expression vector for human wild-type alpha-synuclein gene was constructed successfully. By EGFP fluorescence, anti-alpha-synuclein immunocytochemistry, it could be observed that the alpha-synuclein protein could aggregate in cytoplasm and the Lewy body-like inclusions found in cytoplasm of cultured cells. CONCLUSION: The over-expression of wild-type alpha-synuclein can induce protein aberrant aggregation and Lewy body-like inclusions formation in cytoplasm of HEK293 cell in vitro.

Cells, Cultured↗
PubMed2006

[Genotype and phenotype analyses of three families with autosomal recessive juvenile parkinsonism].

OBJECTIVE: To investigate the gene mutations and the clinical features of Chinese patients with autosomal recessive juvenile parkinsonism(AR-JP). METHODS: the polymerase chain reaction (PCR), DNA sequence analysis, and restriction enzyme digestion analysis were applied to check parkin gene mutations of 15 index patients from 15 families with AR-JP. RESULTS: Three families were detected to have parkin mutations. Two of them had heterozygous deletion mutations (202-203 del AG in exon 2, 1069-1074 del GTGTCC in exon 9) and another of them carried a heterozygous missense mutation [1422(T-->C) in exon 12]. Two of the mutations [1069-1074delGTGTCC and 1422(T-->C)] were not reported previously. There were six patients in the three families. Mean age at onset was 25.2+/-5.7 years, ranging from 18 to 31 years. The symptoms were under slow progression, diurnal fluctuation with sleep benefit, and hyperreflexia were relatively prominent. Response to levodopa was satisfactory. CONCLUSION: There are parkin mutations happened in Chinese patients with AR-JP. Patients with parkin mutations have distinct clinical features besides the common clinical features of Parkinson's disease.

Adult↗
PubMed2006

[Effect of recombinant human growth hormone on growth of human Bel-7402 hepatic carcinoma xenografts in nude mice].

BACKGROUND & OBJECTIVE: Recombinant human growth hormone (rhGH) has been widely used in clinical medicine; while for the patients with hepatocellular carcinoma (HCC), if rhGH could cause tumor growth, metastasis or recurrence other than improve patients' body condition is uncertain. Because most primary hepatic carcinoma could express human growth hormone receptor (GHR), this study was to explore the effects of rhGH on the growth of human Bel-7402 hepatic carcinoma (with GHR expression) xenograft in nude mice. METHODS: The expression of GHR was confirmed in Bel-7402 cells by radioligand assay. After transplantation of Bel-7402 hepatic carcinoma in liver, 32 nude mice were randomly divided into 4 groups. Except 1 control group, 3 experimental groups were injected with different dosages of rhGH [0.5, 1.0, and 2.0 U . (kg.day)(-1), respectively] subcutaneously 2 weeks after tumor transplantation, once a day for 2 weeks. All nude mice were killed at the end of the experiment to observe the growth of xenografts. The expression of proliferating cell nuclear antigen (PCNA) in xenografts was examined by immunochemistry. RESULTS: The tumor weight was significantly heavier and the tumor volume was significantly larger in 1.0 U . (kg.day)(-1) rhGH and 2.0 U . (kg.day)(-1) rhGH groups than in control group (P<0.05), but no significant difference was found between 0.5 U . (kg.day)(-1) rhGH group and control group (P>0.05). Labeling index (LI) of PCNA was significantly higher in each experimental group than in control group (P<0.05), and significant differences were also found among the 3 experimental groups (P<0.05). The dosage of rhGH was positively correlated to LI of PCNA in tumor tissues (r=0.779, P<0.001). CONCLUSIONS: rhGH could enhance the growth of Bel-7402 hepatic carcinoma xenografts in nude mice. Its effect positively correlates with rhGH dosage.

Animals↗
PubMed2006

[Expression and significance of severe acute respiratory syndrome associated coronavirus (SARS-CoV)-X4 protein in lungs of SARS patients].

OBJECTIVE: To investigate the significance of severe acute respiratory syndrome associated coronavirus (SARS-CoV)-X4 protein expression in lungs of patients with SARS. METHODS: Pathological features of the lungs from 4 SARS patients were examined and the expression of SARS-CoV-X4 protein in the lungs was evaluated with immunohistochemical staining using specific antibodies against protein X4. RESULTS: Microscopically, all lungs from 4 cases showed edema, erythrocyte and fibrin exudates in the alveoli, hyperplasia of alveolar epithelium, necrosis, hyaline membrane formation and fibroblast foci. Immunohistochemical stains showed a strong positivity of X4 protein in denudation cells, vascular endothelial cells and also erythrocytes and neutrophils in the alveoli of the lung tissues from the 4 cases. CONCLUSIONS: Expression of SARS-CoV-X4 protein in the lungs may be involved in the pathogenesis and progression of SARS.

Adult↗
PubMed2006

[Expression of soluble GM-CSF-Ralpha in patients with acute myeloid leukemia].

To evaluate soluble GM-CSF-Ralpha expression in patients with acute myeloid leukemia (AML) and its clinic significance, plasma concentration of solGM-Ralpha in de novo 66 patients with AML was detected by enzyme-linked immuno-sorbent assay, and the relationship between solGM-Ralpha levels and various clinical parameters was analyzed. The result showed that the levels of solGM-Ralpha in plasma of patients with AML were significantly higher than that in plasma of normal controls; the lowest level of solGM-Ralpha was found in plasma of patients with AML-M3 (3897.75 +/- 2651.43 pg/ml), the highest level of solGM-Ralpha was observed in plasma of patients with AML-M5 (9990.92 +/- 6325.43 pg/ml). Patients with high level of solGM-Ralpha were generally accompanied with a distinct clinical picture, including higher counts of white blood cell and myeloid precursors, as well as higher expression of CD34, CD95 and CD116 antigen. It is concluded that the high level of solGM-Ralpha in plasma of patients may suggest AML poor prognosis and play a role in pathogenesis of leukemia, the GM-CSF and its receptor solGM-Ralpha needs further study.

Adolescent↗
PubMed2006

[The effects of Helicobacter pylori infection on hyperammonaemia and hepatic encephalopathy in cirrhotic patients].

OBJECTIVE: To evaluate the relationship among Helicobacter pylori (Hp)infection, blood ammonia concentrations, and hepatic encephalopathy (HE) status, and to investigate the effect of Hp eradication on blood ammonia levels and hepatic encephalopathy status in cirrhotic patients. METHODS: From July 2003 to Jan 2005, cirrhotic patients in 5 regions of Zhejiang Province were enrolled. Patients were evaluated for the demographic checklists, number connection test, Hp infection, liver impairment level, blood ammonia concentrations and hepatic encephalopathy status. Patients with Hp infection were given one week therapy with omeprazole plus clarithromycin and tinidazole. (14)C urea breath test was performed and the mental symptoms and blood ammonia levels were reassessed after the eradication therapy. RESULTS: (1) 457 cirrhotics were enrolled, the overall Hp infection rate was 60.6%, and HE happened with 47.5%. Subclinical hepatic encephalopathy (SHE) were detected 55 in 47.0% of 117 cirrhotics. (2) Blood ammonia concentration in Hp (-) and Hp (+) cirrhotics was (53.8 +/- 51.4) micromol/L and (78.4 +/- 63.6) micromol/L respectively (P < 0.01), which was significantly reduced to (53.5 +/- 37.7) micromol/L after Hp eradication (P < 0.01). HE was more frequently observed in patients with Hp infection than without it (58.5% vs 30.6%, P < 0.01). HE rate were significantly dropped to 34.1% after Hp eradication (P < 0.01). (3) Hp prevalence significantly differed among cirrhotic with HE (74.4%), those with SHE (69.1%), or without HE (53.2%) (P < 0.05). The level of blood ammonia had significant difference among the cirrhotics with HE (94.5 +/- 75.6) micromol/L, those with SHE (59.9 +/- 49.2) micromol/L, or without HE (47.3 +/- 33.5) micromol/L (P < 0.05). CONCLUSIONS: Hp infection was an important factor of inducing with high blood ammonia concentration and hepatic encephalopathy in cirrhotic patients. Hp eradication may be helpful for treatment and prevention of HE.

Adult↗
PubMed2005

Morphological evidence for GABA/glycine-cocontaining terminals in synaptic contact with neurokinin-1 receptor-expressing neurons in the sacral dorsal commissural nucleus of the rat.

Previous studies have shown that neurons in the sacral dorsal commissural nucleus (SDCN) express neurokinin-1 receptor (NK1R) and can be modulated by the co-release of GABA and glycine (Gly) from single presynaptic terminal. These results raise the possibility that GABA/Gly-cocontaining terminals might make synaptic contacts with NK1R-expressing neurons in the SDCN. In order to provide morphological evidence for this hypothesis, the triple-immunohistochemical studies were performed in the SDCN. Triple-immunofluorescence histochemical study showed that some axon terminals in close association with NK1R-immunopositive (NK1R-ip) neurons in the SDCN were immunopositive for both glutamic acid decarboxylase (GAD) and glycine transporter 2 (GlyT2). In electron microscopic dual- and triple-immunohistochemistry for GAD/GlyT2, GAD/NK1R, GlyT2/NK1R, or GAD/GlyT2/NK1R also revealed dually labeled (GAD/GlyT2-ip) synaptic terminals upon SDCN neurons, as well as GAD- and/or GlyT2-ip axon terminals in synaptic contact with NK1R-ip SDCN neurons. These results suggested that some synaptic terminals upon NK1R-expressing SDCN neurons co-released both GABA and Gly.

Animals↗
PubMed2005

[Treatment of rabbits bearing advanced VX2 tumors in the mammary gland with nano-sized liposomal adriamycin administered by various routes].

OBJECTIVE: To investigate the therapeutic effect of nano-sized liposomal adriamycin (NLADR) administered by various routes on rabbits bearing advanced breast tumors. METHODS: NLADR with a mean diameter of 120 nm was prepared by pH gradient-driven drug encapsulation method. VX(2) tumor mass suspension was injected into the breast tissues of 50 female New Zealand White rabbits. Six weeks after the inoculation 38 surviving tumor-bearing rabbits were randomly divided into 5 groups: group A (control group), receiving a sham treatment; group B, receiving subcutaneous injection of NLADR with a dose of 1 mg/kg into the areas adjacent to the implanted tumor; group C, receiving intravenous injection of NLADR with a dose of 1 mg/kg; group D, receiving NLADR with a dose of 1 mg/kg administered by subcutaneous injection combined with intravenous injection with half of the whole dose for both routes; and group E, receiving intravenous injection of free adriamycin (FADR). The treatment was repeated every 48 hours. The rabbits were killed 48 hours after the third treatment. The breast tumors, axillary lymph nodes, and all of the metastatic tumors anatomically detected in distant organs were collected. The sizes of tumors and axillary nodes before and after treatment were measured. Necrosis of tumor tissue was assessed pathologically. The mRNA expression of proliferating cell nuclear antigen (PCNA) was determined using RT-PCR. Apoptosis was identified and quantified as apoptosis index (AI) using TUNEL method. RESULTS: The average growth rate of tumor was the highest in group A (1.58) and the lowest in group C (1.33). The average growth rate of axillary lymph nodes was the highest in group A (3.70), significantly higher than in any other groups (all P = 0.00); and was the lowest in group B, significantly lower than groups A, C, and E (all P < 0.01), however without a significant difference between groups B and D (P = 0.148). The PCNA mRNA expression level of the implanted tumor in groups C was the lowest, significant lowest then those in group A and B (both P < 0.01). The sequence of PCNA mRNA in the axillary lymph nodes was group B < group D < group C < group E < group A with significant differences between group B and groups A, C, and E. The sequence of PCNA mRNA in the mediastinal lymph nodes was group B < Group E < group D < group C < group A. The PCNA mRNA expression level was the lowest in group D, significantly lower than that in group A (P = 0.011). Necrosis of implanted tumor, metastatic foci in lung and liver, and lymph nodes was obvious in groups C, D, and E. Necrosis of implanted tumor and metastatic foci in lung and liver was significantly obvious in group C than in group D (P = 0.000 and P = 0.022). Necrosis of the implanted tumor was significantly more obvious in group C than in group F (P = 0.033). Necrosis of axillary lymph nodes was significantly more obvious in group than in groups C and E (P = 0.000 and P = 0.000). The values of AI of the implanted tumor in groups C and D were 16.74% and 18.04%, both significantly higher than those in group E (P = 0.02 and P = 0.04), and those of group E were significantly higher than those in groups A and B (both P < 0.01). The AI value of the axillary lymph nodes was 21.73%, significantly than those in groups A, C, and E (all P < 0.01). The average AI values of the metastatic foci were 16.52%, 15.77%, and 14.50%, all significantly higher than that in group B (all P < 0.01), and that of group B was significantly higher than that in group A (P = 0.039). CONCLUSION: NLADR, especially intravenous administration combined with subcutaneous administration, is effective in treatment of advanced breast carcinoma with lymphatic and distant metastases.

Animals↗
PubMed2005

Functional analysis of a putative Ca2+ channel gene TaTPC1 from wheat.

The cytosolic free-calcium concentration [Ca2+](cyt) transiently increases under abiotic stresses and the proteins that control this process are gradually disclosed. The Ca2+-permeable channel is one type of these proteins in plants. In the present study, a novel Ca2+-permeable channel gene TaTPC1 encoding a putative membrane protein was cloned from wheat. It was induced under high salinity, polyethylene glycol, low temperature (4 degrees C), and abscisic acid. Expression of TaTPC1 in the yeast mutant lacking CCH1 can recover its growth under lithium stress through functional complementation. TaTPC1 transgenic plants exhibited more stomatal closing in the presence of Ca2+ than the control, supporting a role for the calcium channel in regulating plant responses to environmental change.

Amino Acid Sequence↗
PubMed2005

4-Aminobiphenyl induces liver DNA adducts in both neonatal and adult mice but induces liver mutations only in neonatal mice.

The mechanisms underlying the susceptibility of neonatal mice to genotoxic carcinogens were investigated by analyzing the DNA adducts and mutations induced in the livers of neonatal and adult Big Blue transgenic mice by 4-aminobiphenyl (4-ABP), a potent human and rodent carcinogen. Neonatal and adult mice were treated with a regimen of 4-ABP known to induce tumors in neonatal mice. Animals were sacrificed 1 day after the last treatment for DNA adduct analysis and 8 weeks after the last treatment for analysis of lacI and cII mutant frequency (MF). N-(Deoxyguanosin-8-yl)-4-ABP was the major DNA adduct identified in the livers of the 4-ABP-treated mice and levels of this adduct were significantly higher in treated animals than in the controls for both the neonates and adults. Adduct levels for adult females (44.0 +/- 4.8 adducts/10(6) nucleotides) were higher than in neonatal females (25.9 +/- 2.2 adducts/10(6) nucleotides), while adduct levels in adult males (13.5 +/- 2.0 adducts/10(6) nucleotides) were lower than in neonatal males (33.8 +/- 4.1 adducts/10(6) nucleotides). 4-ABP treatment significantly increased the liver cII MFs in both sexes of neonatal mice but not in adult mice. Sequence analysis of cII mutant DNA revealed that 4-ABP induced a unique spectrum of mutations in neonatal mice, characterized by a high frequency of G:C-->T:A transversion, while the mutation spectrum in 4-ABP-treated adults was similar to that of control mice. Our results indicate that DNA adduct formation by 4-ABP depends as much on sex as it does on age, whereas the conversion of DNA adducts into mutations differed with animal age. These observations suggest that neonates are more sensitive than adults to genotoxic carcinogens because the relatively high levels of cell division in the developing animal facilitate the conversion of DNA damage into mutation. Supplementary material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html

Aging↗
PubMed2005

DNA hypomethylation of individual sequences in aborted cloned bovine fetuses.

Cloned bovines have a much higher abortion rate than those derived in vivo. Available evidence indicates that inappropriate epigenetic reprogramming of donor nuclei is the primary cause of cloning failure. To gain a better understanding of the DNA methylation changes associated with the high abortion rate of cloned bovines, we examined the DNA methylation status of a repeated sequence (satellite I) and the promoter regions of two single-copy genes (interleukin 3/cytokeratin) in aborted cloned fetuses, aborted fetuses derived from artificial insemination (AI), cloned adults and AI adults by bisulfite sequencing and restriction enzyme analysis. Two of four aborted cloned fetuses show very low methylation levels in the two single-copy gene promoter regions. One of the two fetuses also showed undermethylated status in the satellite I sequence. The other two aborted cloned fetuses have similar methylation levels to those of aborted AI fetuses. However, no difference in methylation was observed between cloned adults and AI adults. Our results demonstrate for the first time the undermethylated status of individual sequences in aborted cloned fetuses. These findings suggest that aberrant DNA methylation may contribute to the developmental failure of cloned bovine fetuses.

Aborted Fetus↗
PubMed2005

Photomutagenicity of retinyl palmitate by ultraviolet a irradiation in mouse lymphoma cells.

Retinyl palmitate (RP), a storage form of vitamin A, is frequently used as a cosmetic ingredient, with more than 700 RP-containing cosmetic products on the U.S. market in 2004. There are concerns for the possible genotoxicity and carcinogenicity of RP when it is exposed to sunlight. To evaluate the photomutagenicity of RP in cells when exposed to ultraviolet A (UVA) light, L5178Y/Tk+/- mouse lymphoma cells were treated with different doses of RP alone/or in the presence of UVA light. Treatment of the cells with RP alone at the dose range of 25-100 microg/ml did not increase mutant frequencies (MFs) over the negative control, whereas treatment of cells with 1-25 microg/ml RP under UVA light (82.8 mJ/cm2/min for 30 min) produced a dose-dependent mutation induction. The mean induced MF (392 x 10(-6)) for treatment with 25 microg/ml RP under UVA exposure was about threefold higher than that for UVA alone (122 x 10(-6)), a synergistic effect. To elucidate the underlying mechanism of action, we examined the mutants for loss of heterozygosity (LOH) at four microsatellite loci spanning the entire chromosome 11, on which the Tk gene is located. The mutational spectrum for the RP + UVA treatment was significantly different from the negative control, but not significantly different from UVA exposure alone. Ninety four percent of the mutants from RP + UVA treatment lost the Tk+ allele, and 91% of the deleted sequences extended more than 6 cM in chromosome length, indicating clastogenic events affecting a large segment of the chromosome. These results suggest that RP is photomutagenic in combination with UVA exposure in mouse lymphoma cells, with a clastogenic mode-of-action.

Animals↗
PubMed2005

GABAergic neurons express mu-opioid receptors in the ventrolateral orbital cortex of the rat.

Behavioral studies have indicated that GABAergic modulation is involved in the opioid-induced antinociception in the ventrolateral orbital cortex (VLO). The aim of the current study was to examine whether the GABAergic neurons in the rat VLO expressed mu-opioid receptor subtype 1 (MOR1). This study employed immunofluorescence histochemical double-staining technique and showed that a considerable amount of GABA- and MOR1-like immunoreactive neurons existed in layers II-VI in the VLO. Of these GABA-like immunoreactive neurons, 92.0% of them showed MOR1-like immunoreactivities. Similarly, 80.2% of MOR1-like immuoreactive neurons also exhibited GABA-like immunoreactivities. These results provide morphological evidence that opioid-induced antinociception in the VLO might be due to an inhibitory effect by opioid via MOR1 on GABAergic neurons, resulting in disinhibition of VLO projection neurons and leading to activation of the VLO-PAG brainstem descending pain control system to depress the nociceptive inputs at the spinal cord level.

Animals↗
PubMed2005

[Mutation analysis of PINK1 gene in Chinese patients with autosomal recessive early-onset parkinsonism type 6].

OBJECTIVE: To detect PINK1 gene mutations and study the clinical features in Chinese patients with autosomal recessive early-onset parkinsonism (AREP) type 6. METHODS: PINK1 gene mutations were detected using polymerase chain reaction (PCR), DNA sequence analysis, and restriction enzyme digestion analysis in 11 index probands of 11 AREP families. RESULTS: Two novel point mutations in PINK1 gene, C938T in exon four, leading to substitution of a threonine for methionine codon at amino acid 313 (T313M) and C1474T in exon seven introducing a stop codon at amino acid 492 (R492Stop), were found in two families. In another family, a synonymous mutation (Y454Y) was detected. The clinical features in patients with PINK1 mutations included early onset, slow disease progression, hyperreflexia, diurnal fluctuations with sleep benefit, and good response to levodopa. However, dyskinesias related to levodopa treatment were absent. CONCLUSION: PINK1 gene mutations are a common cause of AREP. PARK6 pedigrees have been firstly identified in Chinese Mainland. Clinical heterogeneity exists in PARK6.

Adolescent↗
PubMed2005

Variations of very low-density lipoprotein receptor subtype expression in gastrointestinal adenocarcinoma cells with various differentiations.

AIM: This study is aimed at investigating the expression and possible significances of very low-density lipoprotein receptor (VLDLR) subtypes in gastroenteric adenocarcinoma tissues and cells with various differentiations. METHODS: Thirty-one cases of gastroenteric carcinoma/adjacent normal tissues were enrolled in the study, which were diagnosed and classified by the clinicopathological diagnosis. The expression of VLDLR subtypes was detected in gastroenteric carcinoma/adjacent normal tissues and three various differentiated human gastric adenocarcinoma cell lines (MKN28, SGC7901 and MKN45) by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. RESULTS: Two VLDLR subtypes, namely, type II VLDLR and type I VLDLR, were found to express changes in gastroenteric carcinoma tissues, their adjacent normal tissue, and gastric adenocarcinoma cell lines as well. Type II VLDLR is predominantly expressed in poorly- or moderately-differentiated gastroenteric carcinoma tissues and gastric adenocarcinoma cell lines, whereas type I VLDLR is mainly detected in well-differentiated intestinal carcinoma tissues and gastric adenocarcinoma cells compared with the adjacent normal tissues. CONCLUSION: The results suggested that the variations of the VLDLR subtype expression might be correlated with the progress and differentiation of gastroenteric carcinoma.

Adenocarcinoma↗
PubMed2005

Age-dependent sensitivity of Big Blue transgenic mice to the mutagenicity of N-ethyl-N-nitrosourea (ENU) in liver.

The incidence of childhood cancer is increasing and recent evidence suggests an association between childhood cancer and environmental exposure to genotoxins. In the present study, the Big Blue transgenic mouse model was used to determine whether specific periods in early life represent windows of vulnerability to mutation induction by genotoxins in mouse liver. Groups of mice were treated with single doses of 120 mg N-ethyl-N-nitrosourea (ENU)/kg body weight or the vehicle either transplacentally to the 18-day-old fetus or at postnatal days (PNDs) 1, 8, 15, 42 or 126; the animals were sacrificed 6 weeks after their treatment. The cII mutation assay was performed to determine the mutant frequencies (MFs) in the livers of the mice. Liver cII MFs for both sexes were dependent on the age at which the animals were treated. Perinatal treatment with ENU (either transplacental treatment to the 18-day-old fetus or i.p. injection at PND 1) induced relatively high MFs. However, ENU treatment at PNDs 8 and 15 resulted in the highest mutation induction. The lowest mutation induction occurred in those animals treated as adults (PND 126). For instance, the cII MF for the PND 8 female group was 646 x 10(-6) while the MF for female adults was only 145 x 10(-6), a more than 4-fold difference. Molecular analysis of the mutants found that A:T-->T:A transversions and A:T-->G:C transitions characterized the pattern of mutations induced by ENU in both the neonate and adult mice, while the predominate type of mutation in the controls was G:C-->A:T. The results indicate that mouse liver is most sensitive to ENU-induced mutation during infancy. This period correlates well with the age-dependent sensitivity to carcinogenicity in mouse liver, suggesting that mutation is an important rate-limiting factor for age-related carcinogenesis.

Age Factors↗
PubMed2005

Expression, refolding, and characterization of a novel recombinant dual human stem cell factor.

A novel recombinant dual human stem cell factor (rdhSCF) gene which consisted of a full-length hSCF(1-165aa) cDNA and a truncated hSCF (1-145aa) cDNA, linked by a peptide (GGGGSGGGGSGG) coding region, was constructed and cloned into Escherichia coli expression vector pET-22b. The rdhSCF was expressed at high level in E. coli BL21(DE3) and existed mainly as inclusion bodies. The inclusion bodies were solubilized in urea and refolded by ion-exchange chromatography. After renaturation, the purity of the yielded rdhSCF was up to 90%. Cell proliferation assay showed that the specific activity of the rdhSCF was 2.86x10(5) U/mg, about 1.66 times as high as that of monomer rhSCF expressed in E. coli.

Escherichia coli↗