Stimulation of measles virus replication by cyclic guanosine monophosphate

Measles virus (MV) replication in acutely infected human cells was markedly stimulated following exposure to guanosine 3',5'-monophosphate (cyclic GMP). Addition of cyclic GMP to tissue culture fluids immediately following infection with the virus resulted in acceleration of virus-mediated cell fusion, increased synthesis of virus-specified proteins and a 50-fold increase in infectious particle production. No evidence of altered viral protein phosphorylation was found. The results suggest that cyclic GMP stimulates multiple stages of the MV replication cycle.