RELAXED CONTROL OF NUCLEIC ACID SYNTHESIS BY A MUTANT OF PSEUDOMONAS

Abstract

Synthetic activities of macromolecules by temperature-sensitive mutants of Pseudomonas-P were examined at elevated temperatures. One of the strains, Tm^s-7, exhibited unusually high synthetic activities of protein and nucleic acids under such conditions. Nucleic acid synthesis of this strain continued even in the absence of histidine, which is an amino acid required for growth. No appreciable protein synthesis occurred under these conditions. Analysis of nucleic acids synthesized in a histidine-free medium revealed that radioactive phosphate was incorporated into DNA, soluble and ribosomal RNAs, as well as into other heterogeneous RNAs. The synthesized RNAs were highly susceptible to enzymatic hydrolysis. The relaxed control of nucleic acid synthesis, however, appears to be unrelated to the temperature sensitivity.