THE RELATIONSHIP OF THE NUCLEOLUS TO THE SYNTHESIS OF RIBOSOMAL RNA IN HELA CELLS

Abstract

DNA has been prepared from nucleolus-associated chromatin of isolated nucleoli of HeLa cells grown in suspension culture. The extent of formation of molecular hybrids between this DNA and 28S ribosomal RNA has been determined and compared with hybrid formation between total cell DNA and ribosomal RNA. These experiments demonstrate that there is a concentration of DNA complementary to ribosomal RNA in the nucleolus-associated chromatin. A tentative estimate of the number of cistrons involved in ribosomal RNA production in HeLa cells is presented.