The pools of ribosomal proteins and ribosomal ribonucleic acids during relaxed control of Escherichia coli A19 (Hfr, rel met rns)

Abstract

The soluble fraction extracted from Escherichia coli A19 (Hfr, rel met rns) during early and late times of phenotypic and genotypic induced relaxed control have been examined for the possible accumulation of ribosomal proteins (r-proteins) and rRNA species during this time of unbalanced macromolecular synthesis. Ribosomal proteins and rRNA species were not found to accumulate within the soluble fraction at any time during this period of relaxed control; even after the typical rRNA accumulation had ceased, r-proteins did not accumulate. It is concluded, from these and related observations, that the r-proteins and rRNA species known to be produced during relaxation must immediately associate to form the unusual ribonucleoprotein particles (e.g. 'relaxed particles' and 'chloramphenicol particles') characteristic of periods of relaxed control. Since r-proteins do not accumulate even when net RNA accumulation halts, it appears that some elements of the normal, basic co-ordination between rRNA and r-protein synthesis/stability persist even during relaxed control.