Herpes simplex virus type 1 (HSV-1) is a doublestranded DNA virus with broad host range and mainly causes periodic and repetitive lesions of skins and mucosa. In addition, HSV-1 can present long-term latency in nerval cells or exhibit a potential carcinogenic capability. It is these characteristics that make the HSV-1 an important tool for conducting research in the fields of gene expression regulation, signal transmission, cell apoptosis and gene therapy.
HSV-1 gene expression in lytic infection proceeds in a tightly regulated temporal cascade. Six proteins, termed infected-cell polypeptide 0 (ICP0), ICP4, ICP22, ICP27, ICP47 and US1.5, have been identified as being expressed first. ICP0 has received the most attention due to its potent promiscuous transactivated capability on heterologous viral and cellular promoters in transient assays (3, 10). Moreover, ICP0 has been shown to interact with multiple cellular proteins such as ND10 nuclear structures(12), centomeric protein CENP-C (4), transcription factor BMAL1 (6); translation elongation factor EF-1δ(5), cyclin D3 (7), ubiquitin specific protease USP7(2) and Class Ⅱ histone deacetylases (8), highlighting its involvement in many aspects of host cell metabolism.
Compared to other HSV-1 proteins, expression of entire ICP0 in prokaryotic cells is very difficult--no such evidence has been presented so far. In this study, an antigen peptide of ICP0 was expressed with high efficiency in prokaryotic cells followed by preparation of the relevant antibody. Our results showed that such an antibody can not only recognize the denatured ICP0 protein in vitro, but also the native ICP0 protein in cells. This provides a useful tool for further investigation of its biological function.
Expression of HSV-1 ICP0 Antigen Peptide in Prokaryotic Cells and Preparation of Specific Antibody*
- Received Date: 06 December 2006
- Accepted Date: 27 March 2007
Abstract: As an immediate-early protein of herpes simplex virus, infected-cell polypeptide 0 (ICP0) exhibits complicated interactions with host cells, and its regulatory function on gene expression is of great importance. Since the ICP0 encoding sequence contains many rare codons which are absent in E.coli, and ICP0 is highly unstable in prokaryotic cells, expression of entire ICP0 in prokaryotic cells has never been reported. In order to further investigate the function of ICP0, a recombinant plasmid was constructed by subcloning a cDNA fragment encoding an amino-terminal of 105 residues of the ICP0 protein into pGEX-5x-1 vector. The resulting GST-105 fusion antigen peptide was expressed with high efficiency in E.coli. Antibodies prepared after the immunization of mice with purified fusion protein can recognize not only the denatured ICP0 protein, but also the native ICP0 protein with normal biological conformation.