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. Author manuscript; available in PMC: 2012 Aug 1.
Published in final edited form as: Expert Rev Respir Med. 2011 Oct;5(5):683–697. doi: 10.1586/ers.11.51

Figure 1. Structure and function of simian virus 40.

Figure 1

(A) Physical and functional map of the SV40 genome. The circular DNA genome is 5243 bp. Ori (black). Tag, tag and 17KT (black): ‘Early gene’ mRNAs, controlled by the pE (blue). pL (blue) shares the same sequence with pE, but is oriented in the opposite direction. VP1, VP2, VP3, VP4 and Agno (blue): transcripts of ‘late genes’, are under control of pL and encode capsid proteins VP1, VP2, VP3, and VP4 and Agnoprotein assembly promoting proteins. VP2-4 share the same stop codon. (B) SV40 early proteins: Tag, 17KT and tag share the first 82 amino acid residues at the N-terminal (gray). Tag extends up to 708 residues in length (blue), but skips the tag encoding region (black), owing to differential splicing. 17KT encodes a 135 amino acids protein, sharing the first 131 residues (gray and blue) with Tag, followed by four amino acids encoded by the third intron of the Tag gene, retained by an alternative splicing. SV40 tag is a 174 residue protein.

Ori: Origin of viral DNA replication; pE: Early promoter; pL: Late promoter; SV40: Simian virus 40; Tag: Large T antigen; tag: Small t antigen.