This 1991 review article highlights significant advances in virology research across multiple virus families. Key achievements include the first cell-free synthesis of infectious poliovirus from its RNA genome, establishing a milestone in understanding picornavirus replication. The review extensively covers genomic characterization of hepatitis C and E viruses, recently identified causative agents of non-A, non-B hepatitis. For hepatitis E virus, researchers determined genome sequences revealing three open reading frames and subgenomic transcripts. Hepatitis C virus studies identified at least three major genotypes with high genetic heterogeneity. The article also describes X-ray crystallographic and cryo-electron microscopy structures of parvovirus, adenovirus, and herpesvirus capsids, revealing detailed virion architecture and protein arrangements. Canine parvovirus was shown to undergo rapid antigenic drift despite low mutation rates. Adeno-associated virus type 2 demonstrates site-specific integration into human chromosome 19, with potential applications for gene therapy. These structural and genomic advances provided new frameworks for understanding viral replication, protein function, and virus evolution across diverse families.

Key findings

• First successful cell-free synthesis of infectious poliovirus from RNA genome, demonstrating complete viral replication cycle without intact cells
• Hepatitis C virus identified as belonging to at least three genetically distinct types with 30% amino acid differences, showing high variability particularly in envelope proteins
• Hepatitis E virus genome organization similar to caliciviruses, containing three open reading frames and generating subgenomic transcripts during infection
• Cryo-electron microscopy and X-ray crystallography revealed detailed three-dimensional structures of parvovirus, adenovirus, and herpesvirus capsids, with parvovirus VP2 showing structural similarity to picornavirus capsid proteins
• Adeno-associated virus type 2 integrates site-specifically at chromosome 19 in humans, unique among eukaryotic viruses and relevant for potential gene therapy applications