EFFECTS OF PUROMYCIN ON RNA SYNTHESIS IN MAMMALIAN CELLS

Abstract

Puromycin is a potent inhibitor of protein synthesis both in vitro and in vivo.1, 2In addition, it is known to inhibit RNA replication of several RNA-containing mammalian viruses.3-5In studying this effect on poliovirus RNA synthesis, we have observed a depression of RNA synthesis in control uninfected HeLa cells.This seemed to differ from findings in bacteria where chloramphenicol inhibition of protein synthesis allows continued synthesis of bacterial ribosomal and transfer RNA6' 7 as well as phage messenger RNA.8The present report shows that puromycin inhibits synthesis of 30S and 18S ribosomal RNA and of larger ribosomal precursor RNA.Under the same con- ditions, puromycin is less inhibitory to the synthesis of transfer RNA and to the synthesis of an unstable RNA which may be mammalian cell messenger RNA.After this work was completed, a similar finding of puromycin inhibition of ribo- somal RNA synthesis was published by Tamaoki and Mueller.9The present paper provides inadvertent confirmation of their findings and, at the same time, further documentation and extension of their findings and conclusions.