An arginine-dependent step in the maturation of type 2 adenovirus

Abstract

Of all amino acids in Eagle's basal medium, only arginine is essential for synthesis of complete, infectious progeny virus in KB cells infected with type 2 adenovirus. Omission of any one or all of the other AA's from the medium permits limited virus replication, but none whatever can be detected in absence of medium arginine. When arginine was restored to infected cultures after 28–32 hours of deprivation, infectious virus was made without detectable lag and increased exponentially at the “normal” rate. Simultaneous addition of FUDR failed to inhibit virus production, suggesting that viral DNA had been synthesized in absence of arginine. Accordingly, when thymidine- 3H was added to cultures only during arginine starvation, label was recovered in virus produced following restoration. Immunofluorescence and hemagglutination tests showed that “early” antigen as well as proteins associated with the hexon and penton-fiber subunits were synthesized during the arginine-free period. Thus all previously identified components of the mature virion appear to be made, at least to a limited extent, in the absence of external arginine. When the arginine restored to previously deprived infected cultures was tritium-labeled, radioactivity was associated with the purified virus yield. It is proposed that arginine plays a specific role in a late synthetic step essential for virion maturation.