2601
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Safer B, Yang L, Tolunay HE, Anderson WF. Isolation of stable preinitiation, initiation, and elongation complexes from RNA polymerase II-directed transcription. Proc Natl Acad Sci U S A 1985; 82:2632-6. [PMID: 3857604 PMCID: PMC397618 DOI: 10.1073/pnas.82.9.2632] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Distinct RNA polymerase II transcription preinitiation, initiation, and elongation complexes can be formed in vitro on cloned adenovirus 2 DNA sequences containing the major late promoter. These transcription complexes are stable and can be rapidly isolated by gel filtration of HeLa whole cell extracts. In the absence of exogenous nucleotides and under appropriate salt conditions, a stable but transcriptionally incomplete preinitiation complex is formed. When this complex is incubated in the presence of adenosine or deoxyadenosine triphosphates, the beta-gamma phosphodiester bond is hydrolyzed, and RNA polymerase II joins the complex, thereby converting it into a stable initiation complex capable of forming (but prior to the formation of) the first phosphodiester bond. When this complex is isolated and incubated in the presence of all four nucleoside triphosphates, it is converted into an elongation complex that then permits the synthesis of phosphodiester bonds and the correct run-off transcript. A limiting transcription component is sequestered in the preinitiation complex. This factor is released upon elongation and can reassociate with new DNA templates during subsequent rounds of initiation. Therefore, class II genes do not appear to form activated transcription units stable for multiple rounds of transcription; rather, their transcriptional activity may be controlled in part by regulating the association of transcription factors at each initiation event.
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2602
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Jassby DL, File J, Bertone PC, Graumann DW, Creedon RL, Engholm BA, Hager ER, Lindgren JR, Yang L, Harker YD, Tsang FY. The TFTR Lithium Blanket Module program. JOURNAL OF FUSION ENERGY 1985. [DOI: 10.1007/bf01051639] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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2603
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Yang L, Fergusson GJ, Vestal ML. A new transport detector for high-performance liquid chromatography based on thermospray vaporization. Anal Chem 1984; 56:2632-6. [PMID: 6524649 DOI: 10.1021/ac00278a004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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2604
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Chen GL, Yang L, Rowe TC, Halligan BD, Tewey KM, Liu LF. Nonintercalative antitumor drugs interfere with the breakage-reunion reaction of mammalian DNA topoisomerase II. J Biol Chem 1984; 259:13560-6. [PMID: 6092381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Many intercalative antitumor drugs have been shown to cleave DNA indirectly through their specific effect on the stabilization of a cleavable complex formed between mammalian DNA topoisomerase II and DNA (Nelson, E.M., Tewey, K.M., and Liu, L.F. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 1361-1365). Antitumor epipodophyllotoxins (VP-16 and VM-26) which do not intercalate DNA can similarly induce protein-linked DNA breaks in cultured mammalian cells. In vitro studies using purified mammalian DNA topoisomerase II show that epipodophyllotoxins interfere with the breakage-reunion reaction of mammalian DNA topoisomerase II by stabilizing a cleavable complex. Treatment of this stabilized cleavable complex with protein denaturants results in DNA strand breaks and the covalent linking of a topoisomerase subunit to the 5'-end of the broken DNA. Furthermore, epipodophyllotoxins also inhibit the strand-passing activity of mammalian DNA topoisomerase II, presumably as a result of drug-enzyme interaction. The agreement between the in vivo and in vitro studies suggests that mammalian DNA topoisomerase II is a drug target in vivo. The similarity between the effect of epipodophyllotoxins on mammalian DNA topoisomerase II and the effect of nalidixic acid on Escherichia coli DNA gyrase suggests that the cytotoxic action of epipodophyllotoxins may be analogous to the bactericidal action of nalidixic acid.
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2605
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Chen GL, Yang L, Rowe TC, Halligan BD, Tewey KM, Liu LF. Nonintercalative antitumor drugs interfere with the breakage-reunion reaction of mammalian DNA topoisomerase II. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)90729-5] [Citation(s) in RCA: 261] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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2606
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Tewey KM, Rowe TC, Yang L, Halligan BD, Liu LF. Adriamycin-induced DNA damage mediated by mammalian DNA topoisomerase II. Science 1984; 226:466-8. [PMID: 6093249 DOI: 10.1126/science.6093249] [Citation(s) in RCA: 1060] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Adriamycin (doxorubicin), a potent antitumor drug in clinical use, interacts with nucleic acids and cell membranes, but the molecular basis for its antitumor activity is unknown. Similar to a number of intercalative antitumor drugs and nonintercalative epipodophyllotoxins (VP-16 and VM-26), adriamycin has been shown to induce single- and double-strand breaks in DNA. These strand breaks are unusual because a covalently bound protein appears to be associated with each broken phosphodiester bond. In studies in vitro, mammalian DNA topoisomerase II mediates DNA damage by adriamycin and other related antitumor drugs.
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2607
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Tolunay HE, Yang L, Anderson WF, Safer B. Isolation of an active transcription initiation complex from HeLa cell-free extract. Proc Natl Acad Sci U S A 1984; 81:5916-20. [PMID: 6592595 PMCID: PMC391829 DOI: 10.1073/pnas.81.19.5916] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A two-step procedure has been developed for the formation of RNA polymerase II transcription initiation and elongation complexes. Initiation complexes are rapidly formed in HeLa cell-free extract supplemented with a DNA template containing the adenovirus 2 major late promoter and ATP. Assembly of transcription components required for correct initiation is absolutely dependent on specific eukaryotic promoter sequences. Sarkosyl-sensitive transcription initiation complexes are rapidly converted to Sarkosyl-resistant elongation complexes when supplemented with the remaining nucleoside triphosphates. The 60S initiation complex can be extensively purified by glycerol gradient centrifugation and is easily separated from free RNA polymerase II and free DNA template. Recovery of this stable complex is greater than 90%. Specific transcription cannot be detected if the DNA template is subsequently added to gradient fractions containing HeLa cell-free extract components alone. This suggests that the DNA templates promote the specific assembly of RNA polymerase II and transcription factors required for accurate initiation. Since conversion of purified initiation complexes to elongation complexes can occur without additional HeLa cell components, the presence of transcription components required for initiation and elongation in a single complex is indicated.
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2608
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Huang GJ, Zhang DW, Zhang RG, Wang LJ, Xu PZ, Yang L, Cheng GY, Liu JS, Xiao QL, Mu DX. The role of pneumonectomy in lung cancer. Analysis of 63 cases. Chin Med J (Engl) 1984; 97:79-83. [PMID: 6088181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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2609
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Tolunay HE, Yang L, Kemper WM, Safer B, Anderson WF. Homologous globin cell-free transcription system with comparison of heterologous factors. Mol Cell Biol 1984; 4:17-22. [PMID: 6583493 PMCID: PMC368652 DOI: 10.1128/mcb.4.1.17-22.1984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mouse erythroleukemia (MEL) cells provide a useful model system to examine the regulation of globin gene expression. MEL cells ordinarily do not express globin genes, but in the presence of inducers, such as dimethyl sulfoxide or hexamethylene bisacetamide, they mimic erythroid differentiation. We have developed a cell-free transcription system from uninduced MEL cells to determine the requirements for mRNA synthesis. The MEL system directs accurate transcription of adenovirus type 2 major late DNA and mouse betamaj-globin with an efficiency comparable to those of HeLa and KB cell extracts. Using the procedure of Matsui et al. (T. Matsui, J. Segall, P.A. Weil, and R.G. Roeder, J. Biol. Chem. 255:11992-11996, 1980), we have isolated three active fractions from both MEL and HeLa cell extracts which are required for accurate transcription and have shown that equivalent fractions from MEL and HeLa cell extracts are interchangeable. Our findings suggest that the components required for initiation of transcription are similar in different cell types, at least to the extent that they can be assayed in these in vitro systems.
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2610
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Liu LF, Rowe TC, Yang L, Tewey KM, Chen GL. Cleavage of DNA by mammalian DNA topoisomerase II. J Biol Chem 1983; 258:15365-70. [PMID: 6317692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Using the P4 unknotting assay, DNA topoisomerase II has been purified from several mammalian cells. Similar to prokaryotic DNA gyrase, mammalian DNA topoisomerase II can cleave double-stranded DNA and be trapped as a covalent protein-DNA complex. This cleavage reaction requires protein denaturant treatment of the topoisomerase II-DNA complex and is reversible with respect to salt and temperature. The product after reversal of the cleavage reaction remains supertwisted, suggesting that the two ends of the putatively broken DNA are held tightly by the topoisomerase. Alternatively, the enzyme-DNA interaction is noncovalent, and the covalent linking of topoisomerase to DNA is induced by the protein denaturant. Detailed characterization of the cleavage products has revealed that topoisomerase II cuts DNA with a four-base stagger and is covalently linked to the protruding 5'-phosphoryl ends of each broken DNA strand. Calf thymus DNA topoisomerase II cuts SV40 DNA at multiple and specific sites. However, no sequence homology has been found among the cleavage sites as determined by direct nucleotide-sequencing studies.
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2611
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Zou XD, Qiao FQ, Yang L, Chen LL. Clinical observation on high altitude polycythemia treated with modified Longdan Xiegan Tang. J TRADIT CHIN MED 1983; 3:303-4. [PMID: 6562304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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2612
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Liu LF, Rowe TC, Yang L, Tewey KM, Chen GL. Cleavage of DNA by mammalian DNA topoisomerase II. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)43815-4] [Citation(s) in RCA: 348] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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2613
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Yang L. [Determination of Candida albicans antibody in the saliva and serum of leukoplakia patients]. ZHONGHUA KOU QIANG KE ZA ZHI [CHINESE JOURNAL OF STOMATOLOGY] 1983; 18:250-2. [PMID: 6378554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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2614
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Yang L. [Care of a patient with glomerulonephritis]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1983; 18:293-4. [PMID: 6561075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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2615
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Fang QN, Wu P, Yang L. [Separation and determination of puerarin by high performance liquid chromatography]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 1983; 18:695-9. [PMID: 6677057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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2616
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Yang L. [Relations between infection of Candida albicans and simple leukoplakia of the mouth]. ZHONGHUA KOU QIANG KE ZA ZHI [CHINESE JOURNAL OF STOMATOLOGY] 1983; 18:112-3. [PMID: 6357661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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2617
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Yang L. [Preliminary discussion on the current over-population in agriculture in China]. REN KOU YAN JIU = RENKOU YANJIU 1982:48-9. [PMID: 12339505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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2618
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Huang GJ, Wang LJ, Zhang DW, Wang GQ, Xiao QL, Xu PZ, Yang L, Zhang DC, Mu DX. Surgery in lung carcinoma. A 20-year experience with 576 patients. Chin Med J (Engl) 1982; 95:471-4. [PMID: 6816513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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2619
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Chen Y, Zheng Z, Hu B, Zhang H, Yang L, Ye W. Study on hereditary variations induced by silkworm DNA--mutagenecity of Attacus cynthia ricini by B. mori DNA. SCIENTIA SINICA. SERIES B, CHEMICAL, BIOLOGICAL, AGRICULTURAL, MEDICAL & EARTH SCIENCES 1982; 25:141-51. [PMID: 7100894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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2620
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Yang L, Li SR. The electrogram from sinus venosus of toad recorded in vitro and the effect of high concentration of potassium and calcium on it. ACTA ACADEMIAE MEDICINAE WUHAN = WU-HAN I HSUEH YUAN HSUEH PAO 1982; 2:82-86. [PMID: 7170096 DOI: 10.1007/bf02908870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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2621
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Foreman JW, Yudkoff M, Yang L, Segal S. Circulating cryoglobulins in nephropathic cystinosis. J Pediatr 1981; 98:432-3. [PMID: 7205456 DOI: 10.1016/s0022-3476(81)80714-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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2622
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Liu CR, Tang CC, Yang L. [Effect of rubber seed oil on the development and regression of experimental atherosclerosis of the aorta in rabbits (author's transl)]. ZHONGHUA XIN XUE GUAN BING ZA ZHI 1981; 9:54-7. [PMID: 7261894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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2623
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2624
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Liu CR, Yang L, Yang QY, Tang CC, Zhu XL, He LJ. [Further investigation of the hypolipidemic effect of rubber seed oil. I. The hypolipidemic effect on experimental hyperlipemia in rats (author's transl)]. ZHONGHUA XIN XUE GUAN BING ZA ZHI 1980; 8:60-2. [PMID: 7449619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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2625
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Vale W, Rivier C, Yang L, Minick S, Guillemin R. Effects of purified hypothalamic corticotropin-releasing factor and other substances on the secretion of adrenocorticotropin and beta-endorphin-like immunoactivities in vitro. Endocrinology 1978; 103:1910-5. [PMID: 218793 DOI: 10.1210/endo-103-5-1910] [Citation(s) in RCA: 130] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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