Particles of Nuclear Origin Carrying Rapidly Labelled RNA

Abstract

Nuclei of KB cells have been isolated and incubated at 37° in pH 8.0 saline. The experiments described in this paper provide evidence that: a) Isolated nuclei release well defined nucleoprotein particles, which contain RNAs not detectable in untreated nuclei. b) These particles carry rapidly labelled RNA. c) In cytoplasm they cosediment with the long known smaller ribosomal particles. d) Chase experiments suggest that nuclear particles are precursors of cytoplasmic particles.