1.Selecting EGF-binding Clones From a pⅧ-based Phage Display Library
Weigang TANG ; Jiada LI ; Changlin LI ; Keyi WANG ; Renbao GAN
Progress in Biochemistry and Biophysics 2000;27(4):432-434
Angiogenesis-related diseases involving EGF include acherosclerotic plaques, haemangioma, angiofibroma, tumor growth and arthritis. EGF may serve as a drug target and its antagonists may have important clinical applications.Peptide phage display libraries have been successfully applied in areas of finding ligands for enzymes, receptors, and many other molecules. A pⅧ-based peptide phage display library was panned with the cytokine EGF and several EGF-binding clones were selected based on ELISA and micropanning assays. The selected EGF-binders from peptide phage display library may be utilized in affinity chromatography in EGF downstream processing and even act as potential antagonists of EGF if their affinity is further improved through secondary library strategy.
2.Adenovirus-mediated Expression of Both Antisense Ornithine Decarboxylase (ODC) and S-adenosylmethionine Decarboxylase (AdoMetDC)Inhibits Lung Cancer Cell Growth And Invasion In vitro and In vivo
Hui TIAN ; Xianxi LIU ; Bing ZHANG ; Qifeng SUN ; Dongfeng SUN
Progress in Biochemistry and Biophysics 2007;34(7):709-717
Polyamine biosynthesis is controlled primarily by ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase(AdoMetDC). Antisense ODC and AdoMetDC sequences were cloned into an adenoviral vector (Ad-ODC-AdoMetDCas). To evaluated the effect of recombinant adenovirus Ad-ODC-AdoMetDCas which can simultaneously express both antisense ornithine decarboxylase (ODC) and sadenosylmethionine decarboxylase (AdoMetDC), the human lung cancer cell line A-549, was infected with Ad-ODC-AdoMetDCas as well as with control vector. Viable cell counting, determination of polyamine concentrations, cell apoptosis,and Matrigel invasion assays were performed in order to assess properties of tumor growth and invasiveness. Furthermore,Ad-ODC-AdoMetDCas's anti-tumor effect was also evaluated in vivo in a nude mice xenograft model. It was demonstrated that adenovirus-mediated ODC and AdoMetDC antisense expression could inhibit tumor cell growth, lead to cell apoptosis and reduce tumor cell invasiveness. Polyamine levels were significantly decreased in Ad-ODC-AdoMetDCas-treated cells compared with controls.This adenovirus also induced tumor regression in established tumors in nude mice. It was suggested that as a new anticancer reagent,the recombinant adenovirus Ad-ODC-AdoMetDCas holds promising hope for the therapy of lung cancers.
3.An Expedient Reliable Double Fluorescent Reporter System for φC31 Integrase Function Evaluation
Huanyu XU ; Qingwen MA ; Zhaorui REN ; Zhijuan GONG ; Shuzhen HUANG ; Fanyi ZENG ; Yitao ZENG
Progress in Biochemistry and Biophysics 2009;36(7):929-933
A reporter system for φC31 integrase was developed in NIH3T3 cells. The reporter plasmid coding green fluorescent protein (GFP) coupled with red fluorescent protein (RFP) was eo-transfected with the plasmid coding φC31 integrase, to show the activity of integrase in the cells. Fluorescence activated cell sorter (FACS) was used to measure the proportion of the cells containing red and green fluorescence. The increment of green cells was positively related to the increase in the transfection with plasmid coding φC31 integrase. Approximately 90% of green cells were observed under a ratio of [plasmid-φC31-integrase]/[reporter plasmid] at 10 : 1. This suggests that the φC31 integrase reporter system provides a probe for the function of φC31 integrase in cells.
4.Site-directed Mutagenesis of Arabidopsis Calmodulin Isoform 2 and Its Application in Detecting Calcium-independent Calmodulin-binding Proteins
Li GAO ; Zhenjie WANG ; Sujuan CUI
Progress in Biochemistry and Biophysics 2009;36(7):890-896
Not only calmodulin (CAM) with Ca2+ regulates the activity of many enzymes and proteins, but also free-CaM (no Ca2+bound) and Ca2+-independent CaM-binding proteins play roles in plant and animal cells. There is no in vivo method to identify the interaction between free-CaM and Ca2+-independent CaM-binding protein (CaMBP). Using site-directed mutagenesis by polymerase chain reaction (PCR), 5 mutant Arabidopsis calmodulin isoform 2 (AtCaM2) genes, mCaM21, mCoM212,mCaM2123, mCaM2124 and mCaM21234 were obtained. The mutant mCaM2 encoded glutamine in place of glutamate (E32Q; E68Q; E105Q; E141Q) in one or more EF-hand Ca2+-binding motifs of AtCaM2. The recombinant mCaM2 proteins were produced in Escherichia coli, and subsequently separated on SDS-PAGE in the presence of Ca2+ or EGTA, their electrophoresis mobilities were related with that of mutant EF-hand motifs. 45Ca2+ overlay analysis indicated that the more glutamate replaced by glutamine, the lower affinity with Ca2+ in the mCaM2 proteins. The mCaM21234 mutant protein (E32Q; E68Q; E105Q;E141Q) was unable to bind Ca2+. Using yeast two-hybrid technique with mCaM21234 as bait, it was possible to see interaction in Arabidopsis of AtCaM2 with IQD26, a calcium-independent CaM-binding protein. Site-directed mutation of AtCaM2 will aid the research of Ca2+, CaM and Ca2+-independent CaMBPs in plant biological processes.
5.RNAi-mediated Stable Silencing of HGPRT Expression in Rabbit Fibroblasts and SCNT Embryo Production
Yi GUO ; Chuanshan ZHANG ; Shangang LI ; Feng LI ; Ruihuan GU ; Fengying XING ; Yao LI ; Gang YAO ; Xuejin CHEN
Progress in Biochemistry and Biophysics 2009;36(7):872-879
The hypoxanthine-guanine phosphoribosyl transferase (HGPRT) gene mutation is responsible for gouty arthritis, kidney stone, and Lesch-Nyhan Syndrome (LNS). It has been reported that the expression of HGPRT is decreased or even absent in these diseases. Rabbits are an ideal model for studying the pathology of these diseases. Therefore, the development of an HGPRT-knockdown rabbit model will be highly beneficial m such studies. Stable HGPRT-knoekdown transgenie fibroblast lines were generated by transfecting rabbit fibroblasts with RNA interference (RNAi) plasmids. Polymerase chain reaction (PCR) analyses indicated that the average positive rate was 83.3%. The mRNA and protein levels of HGPRT in the transgenic fibroblast lines were significantly lower than that in the control. Transgenic rabbit blastocysts were derived after performing nuclear transfer. The results show that RNAi can be used to stably knock down expression of the HGPRT in rabbit fibroblasts and further improvements in related technologies will facilitate the use of this method for the generation of HGPRT-knockdown rabbits.
6.Effects of Keratinocyte Growth Factor 2(KGF-2) on Keratinocyte Growth, Migration and on Excisional Wound Healing
Xia CHEN ; Wei HU ; Wangui WEI ; Yan SHEN ; Yan CHEN ; Shengli YANG ; Yi GONG
Progress in Biochemistry and Biophysics 2009;36(7):854-862
Keratinocyte growth factor 2 (KGF-2) is a member of the FGF family that is mainly synthesized by mesenchymal cells and acta predominantly on epithelial cells in a paracrine manner. It is known to play an important role in fetal limb and lung development; skin wound healing and prostatic epithelial cell growth. The KGF-2 coding sequence were isolated from human kidney cDNA library, revealing that the Kgf-2 gene is also expressed in the kidney apparatus. Purified from prokaryotic E. coli cells, the effects of the recombinant KGF-2 protein in cultured keratinocyte were analyzed by using MTT assay and in situ TUNEL assay. Interestingly, results revealed that KGF-2 promoted keratinocyte cell growth by stimulating cell proliferation and attenuating cell apoptosis. These findings supported a few evidences that KGF-2 could contribute to alveolar epithelial cells against apoptosis. Cell migration assays for the first time revealed that KGF-2 could stimulate keratinocyte cell migration in vitro. In addition, in the pilot animal test, recombinant KGF-2 incorporated within the hydrogel dressing exhibited significantly stimulatory effect on cutaneous wound healing. These combined effects implicate a potential therapeutic application of human recombinant KGF-2 in the future.
7.A Practical and Efficient Method for The Retrieval of Ancient DNA Sequence
Ranran LIU ; Jing YUAN ; Xingbo ZHAO ; Ning LI
Progress in Biochemistry and Biophysics 2009;36(11):1495-1502
Retrieval of ancient DNA (aDNA) sequences from organism remains provide direct view of their evolutionary history. However, researches on aDNA have suffered from lots of technical problems. Specifically, discredited sequences were generated from damaged aDNA templates, and expensive and time-consuming methods were employed. Here, a method which could recover the endogenous aDNA as well as to reduce the cost and research period is described. This is achieved by improving the ancient DNA extraction method of isopropanol precipitation, and reevaluating the method of PCR after N-glycosylase (UNG) treatment, which could remove the damaged DNA from the aDNA extract. The efficiency of these methods were tested by comparing with traditional methods using ancient specimens of pig teeth aged between 4 300 years before present (BP) and 3 900 BP. The results showed that: firstly, the extraction efficiency of the improved method of isopropanol precipitation and current method with silica-based spin column were all 60%. Furthermore, the research period at least could be reduced by half with the application of the improved methods and the cost to 1/10 of the current method. Secondly, sequences obtained through the method of PCR after UNG treatment were 100% authentic. In contrast, 66%~ 88% sequences were authentic based on the results obtained with the method of multiple PCRs without UNG treatment. And the research cost and period needed by the method with UNG treatment were only half of the later one. These results demonstrate that the improved extraction method of isopropanol precipitation combined with the method of PCR after UNG treatment could increase the success rate of authentic DNA amplified and at least reduce the research cost and period by half. Therefore, this method can be applied in the large-scale detection of ancient specimens.
8.Fast and Almost 100% Efficiency Site-directed Mutagenesis by The Megaprimer PCR Method
Progress in Biochemistry and Biophysics 2009;36(11):1490-1494
A novel PCR-based mutagenesis method was reported, in which there is no need to purify megaprimers or design a special flanking primer. This method used one mutagenic primer and two sequencing primers (T_m≤58℃) as flanking primers. After first round PCR, 12.5 μl first PCR production was directly added into 50 μl second PCR system as template and megaprimer, and 10 rounds of asymmetrical PCR at high temperature of annealing (68 ℃ ) was to add in initiation of second PCR. This additional step greatly has increased the efficiency of mutagenesis via 600 bp or 800 bp long megaprimer. The results demonstrated that this method can achieve high fidelity, 97%~ 98% efficiency, high yield.
9.Antibacterial Peptides of The Ovine Reproductive Tract
Chen CHEN ; Xinhua WANG ; Xinwen BO
Progress in Biochemistry and Biophysics 2009;36(11):1483-1489
The female sheep reproductive tracts were freshly collected from a local meat processing plant and used as experimental materials. Two antibacterial peptides were isolated and characterized from female sheep reproductive tracts by two consecutive chromatographic steps. The peptide isolation procedures included acetic acid extraction, dialyzed, gel filtration chromatography on Sephadex G-50, and reverse phase high-performance liquid chromatography (RP-HPLC). Their molecular mass were 4 820.47 u and 4 012.5 u, respectively, analyzed by MALDI-TOF-MS. The partial N-terminal amino acid sequences of two peptides were determined as AYVLDEPKP and YDSGA, respectively, by Edman degradation. The antimicrobial activity was tested during each purification step by the radial diffusion plate assay and broth microdilution method. These two peptides showed good antimicrobial activities against reference strains of G~+(S. Aureus ATCC2592 and Streptococcu ATCC55121), G~-(E. Coli ATCC25922) and fungi(C. Albicans ATCC2002). The peptides did not show active hemolytic activity against rabbit blood red cells and had no significant effects on human blood coagulation system. The discovery of antibacterial peptides in sheep reproductive system reveals that antibacterial peptides may play a role in innate immunity against microorganisms in a wide range of animal species.
10.Suppression of ABCE1 Leads to Decreased Cell Proliferation and Increased Apoptosis in 95-D/NCI-H446 Lung Carcinoma Cells
Maogen ZHENG ; Ying GAO ; Bo HUANG ; Dali TIAN ; Chunlu YANG
Progress in Biochemistry and Biophysics 2009;36(11):1475-1482
ATP-binding cassette protein E (ABCE1) has been annotated as an Rnase L inhibitor in eukaryotes. Previous study showed that the overexpression of ABCE1 was related with the occurrence and clinical stage of lung adenocarcinoma. As an initial investigation into the novel functions of ABCE1, siRNA-expressing vectors targeting sites of the ABCE1 gene were constructed from RNAi-Ready pSIREN-DNR-DsRed-Express vector. Cultured 95-D and NCI-H446 lung carcinoma cells were transfected with the siRNA-expressing vectors using FuGENE 6 and transfection efficiency was determined by using fluorescence microscopy. The expression level of ABCE1 protein was determined by Western blot and immunofluorescence staining. Cell viability was determined by MTT, cell cycle was analysed by flow cytometry.The apoptotic rate was observed by ELISA. Fluorescence microscopy showed a satisfactory transfection efficiency which was about 42.70%. Cell viability and the growth fraction were markedly suppressed, whereas the apoptosis was significantly increased in SiRNA-95-D and SiRNA-NCI-H446 cells than controls(P< 0.05). It can be concluded that the siRNA targeting ABCE1 gene shows a dramatic inhibitory effect on RNA transcription and protein expression and a promoting effect on the apoptosis in 95-D/NCI-H446 cells, which offers a reliable base for the further in vivo experiment.