Abstract
With the aid of isotopic techniques the ribonucleic acid (RNA) and protein metabolism of embryonic chicken cells infected with fowl plague virus was studied. In addition to normal cell-RNA only viral RNA was found in the infected cells. The synthesis starts after 1 hour p.i. and proceeds during the rest of the infectious cycle. By labelling the viral subunits (s-antigen and hemagglutinin) with 14C-leucine it could be demonstrated, that the synthesis of their protein components starts also at about 1 hour post infectionem. p-Fluorophenylalanine (FPA) had no influence on the normal RNA and protein metabolism of the cells. If FPA was given immediately after infection, no virus RNA was synthesized. FPA given 2 hours p.i. did not interfere anymore with the production of viral RNA. This was taken as evidence for the existence of an “early protein” necessary for the induction of virus multiplication, s-antigen grown in the presence of FPA and demonstrable by serological methods was not incorporated into the intact virus particle. The findings suggest, that the synthesis of an “early protein” is necessary prior to viral RNA synthesis, that the RNA and the protein of the s-antigen are made simultaneously at the same site, and that the s-antigen acts as a template for the synthesis of the hemagglutinin-protein.