Biophysical Journal 2: 57-82 (1962)
© 1962 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by McCarthy, B. J. Articles by Roberts, R. B. Search for Related Content PubMed Articles by McCarthy, B. J. Articles by Roberts, R. B.

The Synthesis of Ribosomes in E. coli

III. Synthesis of Ribosomal RNA

ABSTRACT

Techniques of chromatography on columns of DEAE¹ cellulose and sedimentation analysis through a sucrose gradient have been used to study the flow of C¹⁴-uracil label through precursors to completed ribosomes. Analysis by chromatography shows the existence of two sequential precursors constituting together some 10 per cent of the total ribosomal RNA. The chromatographic separation into three fractions is ascribed to the lower protein/RNA ratios of the precursor. By sedimentation the primary precursor (eosome) is identified as a component of average sedimentation coefficient 14S. The second precursor stage (neosome) is divided among at least two particles, one of 43S and the other of about 30S. Detailed kinetic analysis shows that all the radioactivity passes through the eosome on its way to finished 50S and 30S ribosomes. The delay in the entry of radioactivity to ribosomes is that expected from the quantity of eosome precursor. The obvious conclusion that there exists a precursor-product relationship is discussed together with possible interpretations.

This article has been cited by other articles:

				C. Guthrie, H. Nashimoto, and M. Nomura Studies on the Assembly of Ribosomes in vivo Cold Spring Harb Symp Quant Biol, January 1, 1969; 34(0): 69 - 75. [Abstract] [PDF]