Summary
Cells of embryos carrying a lethal nucleolar mutation have been maintained in vitro for extended periods of time. Normally these mutants live only 9 to 12 days after fertilization but their cells in culture will survive for more than 3 months. The extent of ribosomal RNA (rRNA) synthesis was determined in primary cultures prepared from normal embryos and nucleolar mutants having different numbers of ribosomal RNA genes. We found that the accumulation of radioactivity into rRNA for normal and mutant embryos was similar in vivo and in vitro. In primary cultures of normal embryos which have two nucleoli per cell and mutant embryos which have only one nucleolus per cell, the incorporation of radio-activity into rRNA was similar even though the normal cells have twice as many rRNA genes. Thus the mechanism which regulates dosage compensation of the rRNA genes operates both in vivo and in vitro.
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References
Wallace, H., and M. L. Birnstiel. 1966. Ribosomal cistrons and the nucleolar organizer. Biochim. Biophys. Acta 114: 296–310.
Brown, D. D., and J. B. Gurdon. 1964. Absence of ribosomal RNA synthesis in the anucleolate mutant ofXenopus laevis. Proc. Natl. Acad. Sci. U.S.A. 51: 139–146.
Knowland, J. S., and L. Miller. 1970. Reduction of ribosomal RNA synthesis and ribosomal RNA genes in a mutant ofXenopus laevis which organizes only a partial nucleolus. I. Ribosomal RNA synthesis in embryos of different nucleolar type. J. Mol. Biol. 53: 321–328.
Miller, L., and J. B. Gurdon. 1970. Mutations affecting the size of the nucleolus inXenopus laevis. Nature 227: 1108–1110.
Miller, L., and J. Knowland. 1970. Reduction of ribosomal RNA genes in a mutant ofXenopus laevis which organizes only a partial nucleolus. II. The number of ribosomal RNA genes in animals of different nucleolar types. J. Mol. Biol. 53: 329–338.
Miller, L., and F. Gonzales. 1976. The relationship of ribosomal RNA synthesis to the formation of segregated nucleoli and nucleolus-like bodies. J. Cell Biol. 71: 939–949.
Nieuwkoop, P. D., and J. Faber. 1967.Normal Table of Xenopus laevis. North-Holland Publishing Co., Amsterdam.
Barth, L. G., and L. J. Barth. 1959. Differentiation of the cells of theRana pipiens gastrula in unconditioned medium. J. Embryol. Exp. Morphol. 7: 210–222.
Balls, M., and L. N. Ruben. 1966. Cultivationin vitro of normal and neoplastic cells ofXenopus laevis. Exp. Cell Res. 43: 694–695.
Laskey, R. A. 1970. The use of antibiotics in the preparation of amphibian cell cultures from highly contaminated material. J. Cell Sci. 7: 653–659.
Miller, L. 1973. Control of 5S RNA synthesis during early development of anucleolate and partial nucleolate mutants ofXenopus laevis. J. Cell Biol. 59: 624–632.
Brown, D. D., and E. Littna. 1964. RNA synthesis during the development ofXenopus laevis. J. Mol. Biol. 8: 669–687.
Zetterberg, A. 1970. Nuclear and cytoplasmic growth during interphase in mammalian cells. In: D. M. Prescott, L. Goldstein, and E. H. McConkey (Eds.),Advances in Cell Biology. Vol. I. Appleton-Century-Crofts, New York, pp. 211–232.
Gurdon, J. B. 1967. Control of gene activity during early development ofXenopus laevis. In: R. A. Brink (Ed.),Heritage from Mendel. University of Wisconsin Press, Madison, pp. 203–241.
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This work was supported by Grant GB38651 from the National Science Foundation.
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Miller, L., Daniel, J.C. Comparison of in vivo and in vitro ribosomal RNA synthesis in nucleolar mutants ofXenopus laevis . In Vitro 13, 557–563 (1977). https://doi.org/10.1007/BF02627851
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DOI: https://doi.org/10.1007/BF02627851