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  • Biochemistry and Biotechnology  (2)
  • c-jun  (2)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 118-122 
    ISSN: 0006-3592
    Keywords: apoptosis ; bcl-2 ; hybridoma ; cell survival ; antibody productivity ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Human bcl-2 DNA was introduced into mouse hybridoma 2E3 cells and expressed at a high level by using BCMGSneo vector, which reportedly amplifies as multiple copies in the cells independently of their chromosomes. The high expression of bcl-2 in BCMGSneo-bcl-2 transfectants was confirmed by western blotting. In batch cultures, the overexpression of bcl-2 raised the maximum viable cell density by 45%, delayed the initiation of apoptosis by 2 days, and prolonged the viable culture period by 4 days. The delayed initiation of apoptosis was detected by emergence of the ladder pattern on DNA electrophoresis and increase of the dead cell number. The bcl-2 transfectants produced lgG1 fourfold per batch culture in comparison with 2E3 cells transfected with BCMGSneo but not with bcl-2: a little less than twofold due to the improved survival of the cells and more than twofold due to the enhanced lgG1 production rate per cell of the bcl-2 transfectants. The method to engineer hybridoma cells genetically with bcl-2 using BCMGSneo vector for increasing viability and productivity would be widely applied for improving antibody productivity of hybridoma cultures. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-0778
    Keywords: antisense ; apoptosis ; cell cycle ; c-jun ; protein production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Expression of c-jun gene induces apoptosis ofcells cultured in serum-free medium. It also promotescell-cycling in serum-containing medium, leading cellsto die by overgrowth. Previously, we established anapoptosis-suppressible, cell-cycle arrestable cellline, c-jun AS, by transfecting Friend murineerythroleukemia (F-MEL) cells with adexamethasone-inducible antisense c-jun gene.Induction of the antisense c-jun transcriptionwith dexamethasone suppressed c-jun expression.As a result, c-jun AS cells survived inserum-free medium containing dexamethasone for a longtime, while F-MEL cells died quickly in the presenceor absence of dexamethasone. In serum-containingmedium, the growth of c-jun AS cells was viablyblocked by inducing antisense c-juntranscription, and the cells survived at thenon-growth state avoiding overgrowth. In the presentstudy, protein productivity of c-jun AS cellswas examined in comparison with that of wild typeF-MEL cells. C-jun AS and F-MEL cells werefurther transfected with a vector for expressingalkaline phosphatase as a protein to be produced, andnamed c-jun AS-SEAP and F-MEL-SEAP cells,respectively. In the serum-free medium withdexamethasone, c-jun AS-SEAP cells produced theprotein for up to 6 days, while F-MEL-SEAP cellsstopped production on day 3 due to cell death causedby serum deprivation. In the serum-containing mediumwith dexamethasone, c-jun AS-SEAP cells wereviably arrested in the cell cycle, and cell death dueto overgrowth was avoided. As the result, they couldproduce the protein for up to 18 days, whileF-MEL-SEAP cells stopped production within 7 days dueto cell death caused by overgrowth.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0006-3592
    Keywords: c-jun ; cell cycle ; apoptosis ; antisense ; growth deprivation ; F-MEL ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: F-MEL cells were transfected with the c-jun antisense gene located downstream of a glucocorticoid-inducible MMTV promoter, and the obtained cells were named c-jun AS cells. When the c-jun AS cells were treated with dexamethasone (DEX) in DMEM supplemented with 10% serum, the growth of the cells was completely suppressed for a duration of 16 days with a high cell viability exceeding 86%. The c-jun expression in the c-jun AS cells was suppressed moderately in the absence of DEX and strongly in the presence of DEX. The c-jun AS cells grew well and reached a density of 106 cells/mL without supplementation of any serum components. Viability was greater than 80% after the cells had been cultured for 8 days in the absence of DEX. The c-jun AS cells stayed at a constant cell density and high viability above 80% for 8 days when they were cultured in the presence of DEX under serum deprivation. In contrast, the wild type F-MEL cells were unable to grow and died by apoptosis in 3 days under serum deprivation. Internucleosomal cleavage of DNA, a landmark of apoptosis, was clearly detectable. Thus the c-jun AS cell line that is resistant to apoptosis induced by serum deprivation and can reversibly and viably be growth-arrested was established. A dual-signal model was proposed to explain the experimental result, the interlinked regulation of apoptosis, and growth by c-jun.© 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:65-72, 1998.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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