Various factors/pathways including hormonal regulation have been suggested to control herpes simplex virus type 1 （HSV-1） latency and reactivation. Our computer analysis identified a DNA repeat containing thyroid ho...Various factors/pathways including hormonal regulation have been suggested to control herpes simplex virus type 1 （HSV-1） latency and reactivation. Our computer analysis identified a DNA repeat containing thyroid hormoneresponsive elements （TRE） in the regulatory region of HSV-1 latency-associated transcript （LAT）. Thyroid hormone （triiodothyronine, T3） functions via its receptor TR （thyroid hormone receptor）, a transcription factor. Present study investigated the roles of TR and T3 in HSV-1 gene expression using cultured neuoroblastoma cell lines. We demonstrated that liganded TR activated LAT transcription, but repressed infected cell protein no. 0 （ICP0） transcription in the presence of LAT TRE. Chromatin immunoprecipitation （CHIP） assays showed that TRs were recruited to LAT TREs independently of T3 and hyperacetylated H4 was associated with the LAT promoter that was transcriptionally active. In addition, ChIP results showed that the chromatin insulator protein CCCTC-binding factor was enriched at the LAT TREs in the presence of TR and T3. In addition, the BRG1 chromatin remodeling complex is found to participate in the T3/TR-mediated LAT activation since overexpression of BRG1 enhanced the LAT transcription and the dominant-negative mutant K785R abolished the activation. This is the first report revealing that TR elicits epigenetic regulation on HSV-1 ICP0 expression in neuronal cells and could have a role in the complex processes of HSV-1 latency/reactivation.展开更多
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...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.展开更多
文摘Various factors/pathways including hormonal regulation have been suggested to control herpes simplex virus type 1 （HSV-1） latency and reactivation. Our computer analysis identified a DNA repeat containing thyroid hormoneresponsive elements （TRE） in the regulatory region of HSV-1 latency-associated transcript （LAT）. Thyroid hormone （triiodothyronine, T3） functions via its receptor TR （thyroid hormone receptor）, a transcription factor. Present study investigated the roles of TR and T3 in HSV-1 gene expression using cultured neuoroblastoma cell lines. We demonstrated that liganded TR activated LAT transcription, but repressed infected cell protein no. 0 （ICP0） transcription in the presence of LAT TRE. Chromatin immunoprecipitation （CHIP） assays showed that TRs were recruited to LAT TREs independently of T3 and hyperacetylated H4 was associated with the LAT promoter that was transcriptionally active. In addition, ChIP results showed that the chromatin insulator protein CCCTC-binding factor was enriched at the LAT TREs in the presence of TR and T3. In addition, the BRG1 chromatin remodeling complex is found to participate in the T3/TR-mediated LAT activation since overexpression of BRG1 enhanced the LAT transcription and the dominant-negative mutant K785R abolished the activation. This is the first report revealing that TR elicits epigenetic regulation on HSV-1 ICP0 expression in neuronal cells and could have a role in the complex processes of HSV-1 latency/reactivation.
基金National natural science foundation items (30570081 and 30670094)
文摘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.
