Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1969 Jan;62(1):88–95. doi: 10.1073/pnas.62.1.88

HYBRIDIZATION OF HAMSTER CELLS WITH HIGH AND LOW FOLATE REDUCTASE ACTIVITY*

John W Littlefield 1,2,3
PMCID: PMC285959  PMID: 5253668

Abstract

These studies concern the question whether diffusible repressors control the syntheses of enzymes in mammalian cells. First, clonal sublines of baby hamster kidney (BHK 21/13) cells in culture were selected in stepwise fashion for resistance to aminopterin. These sublines survived in concentrations of aminopterin that were up to 104 times higher than those tolerated by wild-type cells because they contained up to 125 times as much folate reductase, probably due to overproduction of the enzyme. When five resistant sublines were hybridized to wild-type lines, 32 of 35 hybrid clones contained intermediate levels of reductase activity. This suggests that overproduction of reductase is not due to loss of a diffusible repressor.

Full text

PDF
88

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Attardi G., Huang P. C., Kabat S. Recognition of ribosomal RNA sites in DNA. II. The HeLa cell system. Proc Natl Acad Sci U S A. 1965 Jul;54(1):185–192. doi: 10.1073/pnas.54.1.185. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Britten R. J., Kohne D. E. Repeated sequences in DNA. Hundreds of thousands of copies of DNA sequences have been incorporated into the genomes of higher organisms. Science. 1968 Aug 9;161(3841):529–540. doi: 10.1126/science.161.3841.529. [DOI] [PubMed] [Google Scholar]
  3. Carver D. H., Seto D. S., Migeon B. R. Interferon production and action in mouse, hamster and somatic hybrid mouse-hamster cells. Science. 1968 May 3;160(3827):558–559. doi: 10.1126/science.160.3827.558. [DOI] [PubMed] [Google Scholar]
  4. Changeux J. P. Responses of acetylcholinesterase from Torpedo marmorata to salts and curarizing drugs. Mol Pharmacol. 1966 Sep;2(5):369–392. [PubMed] [Google Scholar]
  5. Davidson R., Yamamoto K. Regulation of melanin synthesis in mammalian cells, as studied by somatic hybridization. II. The level of regulation of 3,4-dihydroxyphenylalanine oxidase. Proc Natl Acad Sci U S A. 1968 Jul;60(3):894–901. doi: 10.1073/pnas.60.3.894. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. FISCHER G. A. Increased levels of folic acid reductase as a mechanism of resistance to amethopterin in leukemic cells. Biochem Pharmacol. 1961 Jul;7:75–77. doi: 10.1016/0006-2952(61)90128-9. [DOI] [PubMed] [Google Scholar]
  7. Finch B. W., Ephrussi B. RETENTION OF MULTIPLE DEVELOPMENTAL POTENTIALITIES BY CELLS OF A MOUSE TESTICULAR TERATOCARCINOMA DURING PROLONGED CULTURE in vitro AND THEIR EXTINCTION UPON HYBRIDIZATION WITH CELLS OF PERMANENT LINES. Proc Natl Acad Sci U S A. 1967 Mar;57(3):615–621. doi: 10.1073/pnas.57.3.615. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Green H., Ephrussi B., Yoshida M., Hamerman D. Synthesis of collagen and hyaluronic acid by fibroblast hybrids. Proc Natl Acad Sci U S A. 1966 Jan;55(1):41–44. doi: 10.1073/pnas.55.1.41. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. HAKALA M. T., ZAKRZEWSKI S. F., NICHOL C. A. Relation of folic acid reductase to amethopterin resistance in cultured mammalian cells. J Biol Chem. 1961 Mar;236:952–958. [PubMed] [Google Scholar]
  10. Hillcoat B. L., Swett V., Bertino J. R. Increase of dihydrofolate reductase activity in cultured mammalian cells after exposure to methotrexate. Proc Natl Acad Sci U S A. 1967 Oct;58(4):1632–1637. doi: 10.1073/pnas.58.4.1632. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. JACOB F., MONOD J. Genetic regulatory mechanisms in the synthesis of proteins. J Mol Biol. 1961 Jun;3:318–356. doi: 10.1016/s0022-2836(61)80072-7. [DOI] [PubMed] [Google Scholar]
  12. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  13. Littlefield J. W., Basilico C. Infection of thymidine kinase-deficient BHK cells with polyoma virus. Nature. 1966 Jul 16;211(5046):250–252. doi: 10.1038/211250a0. [DOI] [PubMed] [Google Scholar]
  14. Marin G., Littlefield J. W. Selection of morphologically normal cell lines from polyoma-transformed BHK21/13 hamster fibroblasts. J Virol. 1968 Jan;2(1):69–77. doi: 10.1128/jvi.2.1.69-77.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Migeon B. R. Hybridization of somatic cells derived from mouse and syrian hamster: evolution of karyotype and enzyme studies. Biochem Genet. 1968 Mar;1(4):305–322. doi: 10.1007/BF00491487. [DOI] [PubMed] [Google Scholar]
  16. Perkins J. P., Hillcoat B. L., Bertino J. R. Dihydrofolate reductase from a resistant subline of the L1210 lymphoma. Purification and properties. J Biol Chem. 1967 Oct 25;242(20):4771–4776. [PubMed] [Google Scholar]
  17. Raunio R. P., Hakala M. T. Comparison of folate reductases of sarcoma 180 cells, sensitive and resistant to amethopterin. Mol Pharmacol. 1967 May;3(3):279–283. [PubMed] [Google Scholar]
  18. Roberts D. An isotopic assay for dihydrofolate reductase. Biochemistry. 1966 Nov;5(11):3549–3551. doi: 10.1021/bi00875a023. [DOI] [PubMed] [Google Scholar]
  19. Rothenberg S. P. A rapid radioassay for folic acid reductase and amethopterin. Anal Biochem. 1966 Jul;16(1):176–178. doi: 10.1016/0003-2697(66)90095-9. [DOI] [PubMed] [Google Scholar]
  20. SPENCER R. A., HAUSCHKA T. S., AMOS D. B., EPHRUSSI B. CO-DOMINANCE OF ISOANTIGENS IN SOMATIC HYBRIDS OF MURINE CELLS GROWN IN VITRO. J Natl Cancer Inst. 1964 Nov;33:893–903. doi: 10.1093/jnci/33.5.893. [DOI] [PubMed] [Google Scholar]
  21. Weiss M. C., Ephrussi B. Studies of Interspecific (Rat x Mouse) Somatic Hybrids. II. Lactate Dehydrogenase and beta-GLUCURONIDASE. Genetics. 1966 Nov;54(5):1111–1122. doi: 10.1093/genetics/54.5.1111. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES