Identification and characterization of the herpes simplex virus type 2 gene encoding the essential capsid protein ICP32/VP19c.
We describe the characterization of the herpes simplex virus type 2 (HSV-2) gene encoding infected cell protein 32 (ICP32) and virion protein 19c (VP19c). We also demonstrate that the HSV-1 UL38/ORF.553 open reading frame (ORF), which has been shown to specify a viral protein essential for capsid formation (B. Pertuiset, M. Boccara, J. Cebrian, N. Berthelot, S. Chousterman, F. Puvian-Dutilleul, J. Sisman, and P. Sheldrick, J. Virol. 63: 2169-2179, 1989), must encode the cognate HSV type 1 (HSV-1) ICP32/VP19c protein. The region of the HSV-2 genome deduced to contain the gene specifying ICP32/VP19c was isolated and subcloned, and the nucleotide sequence of 2,158 base pairs of HSV-2 DNA mapping immediately upstream of the gene encoding the large subunit of the viral ribonucleotide reductase was determined. This region of the HSV-2 genome contains a large ORF capable of encoding two related 50,538- and 49,472-molecular-weight polypeptides. Direct evidence that this ORF encodes HSV-2 ICP32/VP19c was provided by immunoblotting experiments that utilized antisera directed against synthetic oligopeptides corresponding to internal portions of the predicted polypeptides encoded by the HSV-2 ORF or antisera directed against a TrpE/HSV-2 ORF fusion protein. The type-common immunoreactivity of the two antisera and comparison of the primary amino acid sequences of the predicted products of the HSV-2 ORF and the equivalent genomic region of HSV-1 provided evidence that the HSV-1 UL38 ORF encodes the HSV-1 ICP32/VP19c. Analysis of the expression of the HSV-1 and HSV-2 ICP32/VP19c cognate proteins indicated that there may be differences in their modes of synthesis. Comparison of the predicted structure of the HSV-2 ICP32/VP19c protein with the structures of related proteins encoded by other herpes viruses suggested that the internal capsid architecture of the herpes family of viruses varies substantially.
Yei
S P
SP
Department of Microbiology, University of Texas Dental Branch, University of Texas Health Science Center, Houston 77030.
Chowdhury
S I
SI
Bhat
B M
BM
Conley
A J
AJ
Wold
W S
WS
Batterson
W
W
D000595:Amino Acid Sequence; D001483:Base Sequence; D002213:Capsid / Q000235:genetics*; D036022:Capsid Proteins; D002460:Cell Line; D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000235:genetics; D005814:Genes, Viral; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis; D010746:Phosphonoacetic Acid / Q000494:pharmacology; D011487:Protein Conformation; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D018139:Simplexvirus / Q000187:drug effects / Q000235:genetics*; D015678:Viral Structural Proteins / Q000235:genetics*
D036022:Capsid Proteins; D004279:DNA, Viral; C063128:ICP32-VP19c capsid protein, herpes simplex virus type 2; D010455:Peptides; D015678:Viral Structural Proteins; D010746:Phosphonoacetic Acid