par Geuskens, Maurice
Référence Experimental cell research, 39, 2-3, page (400-412)
Publication Publié, 1965-09
Article révisé par les pairs
Résumé : The inhibition of the incorporation of RNA precursors by actinomycin D is much more rapid in the nucleolus than in other cellular sites of starfish oocytes. The labeled RNA synthesized in the nucleolus prior to the inhibitory action remains stable. With the electron microscope, one can observe the transfer of ribonucleic material from the nucleus to the cytoplasm, during the growth of the oocyte. This transfer of material is probably of nucleolar origin and is not inhibited by actinomycin D even for incubation periods up to 5 hr. However, after 17 hr incubation with the inhibitor, one observes no further transfer of material to the cytoplasm of the ovocytes. The nuclei of the oocytes become ameboïd in shape and the nucleoli become fragmented. The nucleolar fragments disaggregate into granules of 150 Å in diameter. These granules pass into the cytoplasm through the "pores" of the nuclear membrane; they have the same appearance as ribosomes. These results are discussed. © 1965.