Molecular Pharmacology, Vol 1, 157-162, Copyright © 1965 by the American Society for Pharmacology and Experimental Therapeutics

Enhanced Messenger Activity of RNA from 8-Azaguanine-Treated Bacillus cereus

¹ Department of Pharmacology, The George Washington University School of Medicine, Washington, D. C.

The messenger activity of total RNA from normal and 8-azaguanine-treated Bacillus cereus cultures was measured by the stimulation of amino acid incorporation into proteins in the preincubated S-30 Escherichia coli system. RNA from 8-azaguanine-treated cells enhanced the incorporation of various amino acids into proteins to a greater extent than did RNA from normal cells.

After sucrose gradient centrifugation, the messenger activity of each individual fraction was tested. Most of this activity in both RNA samples was found to be localized between the 16 S and 4 S fractions. In the RNA from analog-treated cells, however, an appreciably greater proportion of this activity was associated with the ribosomal RNA fraction and extended to particles of 23 S and greater.

The greater total messenger activity in vitro of analog-treated RNA is discussed in relation to the accumulation of precursors of ribosomal RNA with changed secondary structure and having template activity in vitro for amino acid incorporation.

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ACKNOWLEDGMENT We wish to acknowledge the excellent technical assistance of Margit Riis. This research was supported by grants CA 02978 from the National Cancer Institute and AI-04264 from the Institute of Allergy and Infectious Diseases, United States Public Health Service, Bethesda, Maryland.