A possible maturation pathway of calicivirus particles.

The assembly process of feline calicivirus, a representative member of the Caliciviridae, from subunit components in infected cells was monitored by labelling the virus-specific proteins with 3H-leucine for different periods and harvesting cellular extracts at various phases of infection. A series of protein subunit components was detected and the virus assembly process appeared to have occurred in at least two stages. The first stage involved the very rapid aggregation of precursor polypeptides into 5S subunits which possible through several 'unstable' intermediates formed the stable 15S subunit component. The second stage was the association of 15S subunits with the synthesized viral genomes to form the mature infectious FCV particles which sedimented at 170S. Within 30 min of the initiation of protein synthesis, the process of assembly was complete and mature FCV particles appeared in infected cells.