[Transcription complexes in subnuclear fractions isolated from mammalian cells: ultrastructural study].

Miller Beatty's technique was adapted to the study of definite chromatin fractions (nucleolar and nonnucleolar chromatin) isolated from Mammalian cells. The ultrastructural organization of the transcriptional complexes obtained depended on the nuclear compartment studied. In isolated nucleoli, there were "Christmas-tree"-like figures. In nonnucleolar chromatin, the figures were different from the former by the internal structure of the RNP fibrils being synthesized.