This family also contains the NS2 protein. Parvoviruses encode two non-structural proteins, NS1 and NS2. The mRNA for NS2 contains the coding sequence for the first 87 amino acids of NS1, then by an alternative splicing mechanism mRNA from a different reading frame, encoding the last 78 amino acids, makes up the full length of the NS2 mRNA [2]. NS1, is the major non-structural protein. It is essential for DNA replication. It is an 83-kDa nuclear phosphoprotein. It has DNA helicase and ATPase activity [1].

1: Nuclear targeting of the parvoviral replicator molecule NS1: evidence for self-association prior to nuclear transport. Nuesch JP, Tattersall P; Virology 1993;196:637-651. PMID:8372437

2: Nonstructural protein-2 and the replication of canine parvovirus. Wang D, Yuan W, Davis I, Parrish CR; Virology 1998;240:273-281. PMID:9454701