Ribosome formation by puromycin-treated Bacillus subtilis

Abstract

Puromycin causes an unbalanced synthesis of RNA in Bacillus subtilis, while net increase in protein of the cell is prevented. Under these conditions, an accumulation of abnormal particles (between 18 S and 25 S) containing newly formed ribosomal RNA (16 S and 23 S) occurs. Experiments on the fate of the RNA contained in these particles have provided the following information. 1. 1. The ribosomal RNA contained in the abnormal particles is unstable, as indicated by its degradation to acid-soluble material when synthesis of RNA de novo is blocked by actinomycin D. 2. 2. When puromycin is removed from the culture, most of the pre-formed ribosomal RNA is incorporated into ribosomes by combining with ribosomal protein synthesized preferentially by the recovering cells. 3. 3. The preferential synthesis of ribosomal protein during recovery from puromycin treatment can also occur in the presence of actinomycin D, resulting in incorporation of some of the pre-formed RNA directly into ribosomes. An accumulation of the information for ribosomal protein during puromycin treatment is indicated.