Molecular cloning and characterization of the pseudorabies virus US1 gene

M.L. Li, J.H. Chen, Z.Y. Zhao, K.J. Zhang, Z. Li, J. Li, J.Y. Mai, X.M. Zhu and M.S. Cai
Published January 22, 2013
Genet. Mol. Res. 12 (1): 85-98 (2013)

About the authors
M.L. Li, J.H. Chen, Z.Y. Zhao, K.J. Zhang, Z. Li, J. Li, J.Y. Mai, X.M. Zhu and M.S. Cai

Corresponding author
M.S. Cai


Using polymerase chain reaction, a 1050-bp sequence of the US1 gene was amplified from the pseudorabies virus (PRV) Becker strain genome; identification of the US1 gene was confirmed by further cloning and sequencing. Bioinformatics analysis indicated that the PRV US1 gene encodes a putative polypeptide with 349 amino acids. The encoded protein, designated PICP22, had a conserved Herpes_IE68 domain, which was found to be closely related with the herpes virus immediate early regulatory protein family and is highly conserved among the counterparts encoded by Herpes_IE68 genes. Multiple nucleic acid sequence and amino acid sequence alignments suggested that the product of PRV US1 has a relatively higher homology with ICP22-like proteins of genus Varicellovirus than with those of other genera of Alphaherpesvirinae. In addition, phylogenetic analysis showed that PRV US1 has a close evolutionary relationship with members of the genus Varicellovirus, especially Equid herpes virus 1 (EHV-1), EHV-4 and EHV-9. Antigen prediction indicated that several potential B-cell epitopes are located in PICP22. Also, subcellular localization analysis demonstrated that PICP22 is predominantly located in the cytoplasm,suggesting that it might function as a cytoplasmic-targeted protein.

Key words: Pseudorabies virus; US1; ICP22; Cloning; Bioinformatics; Molecular characterization

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