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Studies of Human-Mouse Cell Hybrids with Respect to X-Chromosome Inactivation

  • Barbara R. Migeon
  • Joyce A. Sprenkle
  • Tai T. Do
Part of the Basic Life Sciences book series (BLSC, volume 12)

Abstract

As a means of obtaining insights into the mechanisms for maintaining X-chromosome inactivation, we have carried out a series of experiments in an attempt to reverse the process. To identify cells in which the silent X has been derepressed, we have developed a model based on the one described by Comings (1966) using human fibroblasts heterozygous for the common A electrophoretic variant of glucose-6-phosphate dehydrogenase (G6PDA). In our model, however, the cells are also heterozygous for the Lesch-Nyhan mutation specifying deficiency of hypoxanthine guanine phosphoribosyl transferase (HGPRT-), so that we can select for rare cells in which reactivation has occurred (Migeon 1972). Clonal populations of skin fibroblasts from females heterozygous for both G6PDA and HGPRT-, but expressing only the alleles on the active X, are subjected to a variety of treatments, and the phenotype with regard to both loci is ascertained following treatment. The resultant phenotype is interpreted according to Table 1. The G6PD heteropolymer, because it is never found in mixtures of the two cells under conditions used for these studies, is a sensitive indicator of two functional X chromosomes within the same cell, while the presence of variants at two X-linked loci helps distinguish reactivation from other events such as reversion, somatic crossing over, or contamination with cells of other phenotype.

Keywords

Hybrid Clone Fibroblast Clone HGPRT Activity Human G6PD Somatic Exchange 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Coinings, D. E. 1966. The inactive X chromosome. The Lancet ii: 1137–1138.CrossRefGoogle Scholar
  2. Corsaro, C. M. and B. R. Migeon. 1978. Gene expression in euploid human hybrid cells: Ouabain-resistance is codominant. Somat. Cell Genet., in press.Google Scholar
  3. Davidson, R. G., H. M. Nitowsky, and B. Childs. 1963. Demonstrations of two populations of cells in the human female heterozygous for glucose-6-phosphate dehydrogenase variants. Proc. Natl. Acad. Sci. USA 50: 481–485.PubMedCrossRefGoogle Scholar
  4. Davidson, R. and P. Gerald. 1976. Improved techniques for the induction of mammalian cell hybridization by polyethylene glycol. Som. Cell Genet. 2 : 165–176.CrossRefGoogle Scholar
  5. Der Kaloustian, V. M., R. Byrne, W. J. Young, and B. Childs. 1969. An electrophoretic method for detecting hypoxanthine-guanine phos-phoribosyl transferase variants. Biochem. Genet. 3: 299.CrossRefGoogle Scholar
  6. Harris, H., J. F. Watkins, C. E. Ford, and G. I. Schoefl. 1966. Artificial heterokaryons of animal cells from different species. J. Cell Sci. 1: 1–30.PubMedGoogle Scholar
  7. Kahan, B. and R. DeMars. 1975. Localized derepression on the human inactive X chromosome in mouse-human cell hybrids. Proc. Natl. Acad. Sci. USA 72: 1510–1514.PubMedCrossRefGoogle Scholar
  8. Meera Khan, P. 1971. Enzyme electrophoresis on cellulose acetate gel: Zymogram patterns in man-mouse and man-uinen hamster somatic cell hybrids. Arch, of Biochem. and Biophys. 145: 470–483.CrossRefGoogle Scholar
  9. Migeon, B. R. 1972. Stability of X chromosome inactivation in human somatic cells. Nature 239: 87–89.PubMedCrossRefGoogle Scholar
  10. Migeon, B. R. and J. F. Kennedy. 1975. Evidence for the inactivation of X chromosome early in the development of the human female. Amer. J. of Hum. Genet. 27 : 233–239.Google Scholar
  11. Migeon, B. R., R. A. Norum, and C. M. Corsaro. 1974. Isolation and analysis of somatic hybrids from two human diploid cells. Proc. Natl. Acad. Sci. USA 71: 937–941.PubMedCrossRefGoogle Scholar
  12. Peterson, J. and M. Weiss. 1972. Expression of differentiated functions in hepatoma cell hybrids: Induction of mouse albumin production in rat hepatoma-mouse fibroblast hybrids. Proc. Nat. Acad. Sci. 69: 571–575.PubMedCrossRefGoogle Scholar
  13. Romeo, G. and B. R. Migeon. 1975. Stability of X chromosomal inactivation in human somatic cells transformed by SV-40. Humangenetik 29: 165–170.PubMedCrossRefGoogle Scholar
  14. Tavares, A. S. 1966. Sex chromatin in tumors. In, The Sex Chromatin, K. L. Moore, Ed. Saunders, Philadelphia, pp. 405–433.Google Scholar

Copyright information

© Plenum Press, New York 1978

Authors and Affiliations

  • Barbara R. Migeon
    • 1
  • Joyce A. Sprenkle
    • 1
  • Tai T. Do
    • 1
  1. 1.Department of Pediatrics, School of MedicineJohns Hopkins UniversityBaltimoreUSA

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