INTERVENTION OF RNA IN LIVING CELLS 31 



Staphylococci themselves, largely restores the activity of the system. 



Another important observation of Gale and Folkes (1954, 1955a) 

 is that the addition of a mixture of purines and pyrimidines stimu- 

 lates the induced synthesis of glucozymase in their disrupted staphylo- 

 cocci system, provided that amino acids are also present. After 

 the disrupted cells have been depleted of their nucleic acids, addi- 

 tion of staphylococcal nucleic acids stimulates the induced enzyme 

 synthesis. RNA is more effective for catalase synthesis than DNA, 

 while the latter is required to restore /5-galactosidase synthesis. 



The experimental results, as pointed out by Gale and Folkes 

 (1954), can be accounted for by the following hypothesis: DNA, 

 perhaps associated with a protein, is an initial organizing structure. 

 It is incapable of synthesizing protein itself, but it acts as an organ- 

 izer for the synthesis of RNA. Once RNA has been synthesized, 

 protein synthesis can take place at a rate dependent upon the 

 amount of the specific RNA present. 



More recently, Gale and Folkes (1955b) and Gale (1956a, b) 

 have reported on important developments of this work. While un- 

 specific RNA from yeast or liver is unable to restore the incorpo- 

 ration of amino acids into the proteins, ribonuclease digests of 

 these ribonucleic acids are active. In the case of the staphylococcal 

 nucleic acids, DNA loses some of its activity on digestion. In con- 

 trast, the stimulating activity of staphylococcal RNA is enhanced 

 after the digestion. These observations led Gale and Folkes (1955b) 

 to an extensive fractionation of staphylococcal RNA digests by 

 chromatography and ionophoresis. Various fractions could be 

 isolated, which promoted the incorporation of the various amino 

 acids to different extents. Some of ths fractions obtained were at 

 least 100 times more active than the initial RNA. Gale's conclusion 

 was (1956 b) "that the whole RNA complex is not necessary for 

 the incorporation of any particular amino acid and that RNA can 

 be replaced by small fragments obtained by ribonuclease digestion 

 of the whole RNA structure". 



Gale's (1956 a, b) efforts to purify the active fraction present in 

 the ribonuclease digest have recently been concentrated on the 

 factor which promotes the incorporation of glycine (GIF). Un- 



References p. 50/54 



