ARTICLE

SITES OF NUCLEOLUS PRODUCTION IN CULTURED CHINESE HAMSTER CELLS

Stephanie Gordon Phillips ¹ and David M. Phillips ¹

¹ From the Laboratory of Cytogenetics, Children's Cancer Research Foundation, Boston, Massachusetts 02115; the Whitman Laboratory, Department of Zoology, The University of Chicago, Chicago, Illinois 60637; and the Department of Anatomy, Harvard Medical School, Boston, Massachusetts 02115. The authors' present address is Department of Biology, Washington University, St. Louis, Missouri 63130

Chinese hamster cell strains in the early passages in culture display wide variation in number of nucleolus-like bodies per cell, though such strains are characteristically euploid. A variety of criteria indicate that the nucleolus-like bodies are true nucleoli. Their Azure B- and fast green-staining properties indicate the presence of RNA and protein; they have typical nucleolar fine structure, including both fibrous and granular components; radioautography reveals that their patterns of uptake of uridine-³H into RNA are similar to those reported for nucleoli of other cell types; actinomycin D, at a level which selectively inhibits ribosomal RNA synthesis, greatly reduces their RNA synthesis and also causes segregation of fibrous and granular nucleolar components. Colchicine was used to experimentally fragment the nuclei of these cells into a number of separate karyomeres, each presumably containing some, or only one, of the chromosomes of the complement. Almost all the karyomeres contain nucleolus-like bodies which, by the same criteria applied to the multiple nucleolus-like bodies of uninuclear cells, appear to be true nucleoli. The nucleoli of individual karyomeres of the same cell often differ from each other in fine structure while the multiple nucleoli of a uninuclear cell generally resemble each other. The evidence presented in this study indicates that Chinese hamster cells contain many nucleolus-producing sites scattered through the genome.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Emerson, C. P. Jr., Humphreys, T. (1971). Ribosomal RNA Synthesis and the Multiple, Atypical Nucleoli in Cleaving Embryos. Science 171: 898-901 [Abstract]  

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents