DNA replication of human cytomegalovirus (HCMV) is a highly regulated process that requires specific interactions between cis-acting lytic origin of replication (oriLyt) and trans-acting viral proteins. Formation of the replication initiation complex is also regulated by specific interactions among viral replication proteins. HCMV replication proteins include origin-binding proteins, core proteins that work in replication forks, and regulatory proteins that modulate host cell functions. This letter describes intriguing questions regarding how HCMV origin-binding proteins interact with oriLyt to initiate DNA replication and how the regulatory UL112-113 proteins, which are found only in beta-herpesviruses, function to promote viral DNA replication.
Cytomegalovirus ; DNA ; DNA Replication ; DNA, Viral ; Humans ; Proteins ; Replication Origin ; Viral Proteins

Varicella-zoster virus (VZV) is a causative agent for shingles and herpes zoster. The genomes of VZV contain five reiteration (R) sequences and an origin of replication (ORI) sequences composed of tandem repeats whose numbers vary among different strains. Variation of the genome lengths among VZV strains could be attributed by the lengths of R sequences. There was a strong correlation between the lengths of VZV genome and R sequences, while variation of ORI did not contribute the variation of VZV genome length. The high G+C contents of The R sequences in ORF11, 14 and 22 influenced the codon usage of VZV in these ORFs. None of the most frequent 5 codons in R sequences was included in the top 5 most frequent codon in ORF11-14-22 or VZV genome, and vice versa.
Animals ; Base Composition ; Codon ; Ecthyma, Contagious ; Genome ; Herpes Zoster ; Herpesvirus 3, Human* ; Open Reading Frames ; Replication Origin ; Tandem Repeat Sequences

Streptoverticillum caespitosus ATCC27422 is a producing strain of mitomycin A for cancer therapy. Taking the advantage of the conserved sequences of genes flanking the oriC of high G + C Gram-positive bacteria, a 1.3 kb DNA fragment containing oriC and its flanking region was cloned by PCR. Nuleotide sequence comparisons revealed that the cloned fragment is more than 80% identical to the same region of S. coelicolor. There are 22 DnaA-boxes in the oriC region, and the conserved sequence of DnaA-box is TTGTCCACA. The plasmid containing the oriC of S. caespitosus was constructed (pMJ9), and it was able to transform the protoplast of Streptomyces lividans ZX7 at the frequency of 3.2 x 10(2) transformants/micrograms plasmid DNA. The colony and mycelia's morphology of the transformants are normal. The constructed plasmid can exist stable in the host as a low copy extra-chromosome replicon. The high rate of the homology and the cross genus replication initiation activity suggests close relationship between Streptomyces and Streptoverticillum in the evolution. While the maximum likelihood phylogenetic tree based upon the oriC of S. caespitosus and several Streptomyces spp. revealed that S. caespitosus differed extensively from the Streptomyces spp. This result supports the separation of Streptoverticillum from Streptomyces.
Actinomycetales ; genetics ; Base Sequence ; Blotting, Southern ; Cloning, Molecular ; Conserved Sequence ; Molecular Sequence Data ; Plasmids ; Replication Origin ; genetics ; Streptomyces ; genetics ; Transformation, Bacterial

HIV-1 p24 was cloned into multiple cloning site of pMV261, extrachromosomal expression vectors carrying BCG replication origin and BCG-specific heat-shock promoter, and then introduced into BCG and E. coli. Western blot experiments showed that the p24 efficiently expressed in recombinant BCG (rBCG), but not in E. coli. Recombinant p24 expression induced by a single heat-shock of rBCG was maintained longer than 3 weeks. Immunoblot experiments with intact rBCG did not show any distinctive positive signal, suggesting that the recombinant protein was not secreted or exposed at the surface of BCG. The guinea pigs immunized with live rBCG showed delayed type hypersensitivity (DTH) by the systemic area as well as an effective humoral immunity, suggesting that tbis rBCG is believed to elicit eKcient immune responses against p24, even though the expression is restricted only in the cytoplasm as reported previously with other antigen. These results demonstrate that BCG can be developed as a live recombinant vaccine vector against a broad spectrum of infectious disease.
Animals* ; Blotting, Western ; Clone Cells ; Cloning, Organism ; Communicable Diseases ; Cytoplasm ; Guinea Pigs ; HIV* ; HIV-1 ; Hypersensitivity ; Immunity, Humoral ; Mycobacterium bovis* ; Replication Origin

Recently the reverse genetics system contributed to the progresses in the investigation of positive-stranded RNA viruses. Here, we report the successful construction of a stable full-length infectious cDNA clone of the live attenuated JEV vaccine strain SA14-14-2. The eleven kilobase viral RNA genome was reverse transcribed, amplified as four overlapping DNA fragments and successively ligated into the low copy number plasmid pACYC184, which contains the p15A origin of replication. In vitro-transcribed RNAs had a specific infectivity of approximately 104 PFU/microgram RNA, and the resulting virus exhibited growth kinetics and plaque morphology similar to the parental virus in cell culture. The structural and functional integrity of the cDNA clone was stably maintained even after at least 150 generations in Escherichia coli strain TOP10. The cDNA clone was engineered to contain single nucleotide change to create a XhoI site and knock out a XbaI site (A to C at nt 9134) acting as a genetic marker. This genetic marker was retained in the recovered progeny virus. Our results suggest that the instability of the full-length infectious JEV cDNA clone can be overcome by employing low copy number plasmid pACYC184. This infectious JEV cDNA clone will aid future studies of pathogenesis, virulence, and replication. Furthermore, it will facilitate the development of SA14-14-2 based recombinant vaccines.
Asian Continental Ancestry Group* ; Cell Culture Techniques ; Clone Cells* ; DNA ; DNA, Complementary* ; Encephalitis Virus, Japanese* ; Encephalitis, Japanese* ; Escherichia coli ; Family Characteristics ; Genetic Markers ; Genome ; Humans ; Kinetics ; Parents ; Plasmids* ; Replication Origin ; Reverse Genetics ; RNA ; RNA Viruses ; RNA, Viral ; Vaccines, Synthetic ; Virulence

Recently the reverse genetics system contributed to the progresses in the investigation of positive-stranded RNA viruses. Here, we report the successful construction of a stable full-length infectious cDNA clone of the live attenuated JEV vaccine strain SA14-14-2. The eleven kilobase viral RNA genome was reverse transcribed, amplified as four overlapping DNA fragments and successively ligated into the low copy number plasmid pACYC184, which contains the p15A origin of replication. In vitro-transcribed RNAs had a specific infectivity of approximately 104 PFU/microgram RNA, and the resulting virus exhibited growth kinetics and plaque morphology similar to the parental virus in cell culture. The structural and functional integrity of the cDNA clone was stably maintained even after at least 150 generations in Escherichia coli strain TOP10. The cDNA clone was engineered to contain single nucleotide change to create a XhoI site and knock out a XbaI site (A to C at nt 9134) acting as a genetic marker. This genetic marker was retained in the recovered progeny virus. Our results suggest that the instability of the full-length infectious JEV cDNA clone can be overcome by employing low copy number plasmid pACYC184. This infectious JEV cDNA clone will aid future studies of pathogenesis, virulence, and replication. Furthermore, it will facilitate the development of SA14-14-2 based recombinant vaccines.
Asian Continental Ancestry Group* ; Cell Culture Techniques ; Clone Cells* ; DNA ; DNA, Complementary* ; Encephalitis Virus, Japanese* ; Encephalitis, Japanese* ; Escherichia coli ; Family Characteristics ; Genetic Markers ; Genome ; Humans ; Kinetics ; Parents ; Plasmids* ; Replication Origin ; Reverse Genetics ; RNA ; RNA Viruses ; RNA, Viral ; Vaccines, Synthetic ; Virulence

The study aimed to construct the amplicon vector of HSV-1 strain HF and explore its universal package function between different serotypes of HSV. OriS and pac elements were obtained by enzyme digestion from the Plasmid BAC-HSV-1 strain HF and sequenced. With red fluorescence (DsRed) as a reporter gene, the amplicon vector of HSV-1 strain HF was constructed based on pSilencer2.0-U6. The amplicon vector was transfected into Vero cells by lipofectamine 2000, then packaged by HSV-1 strain HF and HSV-2 strain HG52 as helper virus separately. The supernatant was collected after cytopathic effect. Red fluorescence was observed in Vero cells reinfected by the supernatant. In this study,the amplicon vector of HSV-1 strain HF was successfully constructed and it could be packaged by HSV-1 strain HF and HSV-2 strainHG52.
Animals ; Base Sequence ; Cercopithecus aethiops ; Gene Order ; Genes, Viral ; genetics ; Genetic Vectors ; genetics ; Herpesvirus 1, Human ; classification ; genetics ; Herpesvirus 2, Human ; genetics ; Molecular Sequence Data ; Replication Origin ; genetics ; Serotyping ; Vero Cells

The nonviral gene delivery systems are usually not very effective in transferring gene into target cells, and the intensity and duration of the gene expression is very poor. The EBNA1/oriP maintain EBNA1/oriP-based plasmids as episome, contribute to nuclear transport of the plasmid and transcriptional up-regulation of target gene. The EBNA1/oriP based plasmid enhances the transfection rate as well as magnitude and longevity of gene expression. This article reviews recent preclinical gene therapy studies with the EBV plasmid vectors conducted against various diseases. For gene therapy against malignancies, the EBNA1/ oriP based plasmid encoding the HSV1-TK suicide gene was combined with a cationic polymer to transfer into HCC cell line. The expression level of TK gene was 100- to 1000-fold higher than the conventional plasmid. The sensitivity of HCC to ganciclovir (GCV) elevated several hundred-fold. The EBNA1/oriP based plasmid equipped with tumor specific promoter, such as CEA promoter, enabled targeted killing of CEA-positive tumor cell. Transfection of EBNA1/oriP based plasmid carrying IL-12 and IL-18 gene either locally, or systemically, induced therapeufic antitumor immune responses including augmentation of the cytotoxic T lymphocyte and natural killer activities and growth retardation of tumors. For gene therapy of congenital diseases and chronic diseases, the EBNA1/oriP based plasmid encoding the adenosine deaminase gene was transfered into human hematopoietic progenitor cells. The ADA activity was elevated 1.5-to 2-fold. Intracardiomuscrlar transfer of the EBNA1/oriP based plasmid encoding the beta-AR gene may be useful for the treatment of severe heart failure. Human tumor necrosis factoralpha (hTNFalpha) is one of the most important inflammatory cytokines. It has been implicated in many autoimmune and inflammatory diseases. sTNFR can efficiently neutralize the bioactivities of hTNFalpha. In primary study we cloned the chimeric protein sTNFR II-IgG Fc and expect to use it in the gene therapy of the inflammatory disease relative to TNF. In summary, The EBNA1/oriP based plasmid shows advantage in gene therapy of cancer, congenital and inflammatory diseases. Moreover, the EBNA1/oriP element may greatly contribute to the engineering of a human artificial chromosome, the ultimate device for controllable gene therapy.
Epstein-Barr Virus Nuclear Antigens ; genetics ; Genetic Therapy ; methods ; Genetic Vectors ; genetics ; Herpesvirus 4, Human ; genetics ; metabolism ; Humans ; Muscular Dystrophy, Duchenne ; therapy ; Neoplasms ; therapy ; Plasmids ; genetics ; Replication Origin ; genetics ; Transcription, Genetic ; Transfection ; methods

Murine gammaherpesvirus 68 (MHV-68), a member of the gammaherpesvirus family, replicates robustly in permissive cell lines and is able to infect laboratory mice. MHV-68 has emerged as a model for studying the basic aspects of viral replication and host-virus interactions of its human counterparts. Herpesvirus genome replication is mediated through a cis-element in the viral genome called the origin of lytic replication (oriLyt). A family of transcription factors, CCAAT/enhancer binding proteins (C/EBPs), assists in oriLyt-mediated DNA replication during gammaherpesvirus reactivation. In this study, we examined the role of C/EBPs in gammaherpesvirus DNA replication during de novo infection, using MHV-68 as a model. We found that C/EBP α and β bind to the CCAAT boxes in the MHV-68 oriLyt core region both in vitro and in vivo, as demonstrated by electrophoretic mobility shift assay and chromatin immunoprecipitation assay. A dominant negative form of C/EBPs significantly impaired the lytic replication efficiency of MHV-68 on both the plasmid and genome levels in a replication assay, indicating that functional C/EBPs are required for maximal MHV-68 genome DNA replication. Collectively, our data demonstrate that C/EBPs interact with the oriLyt core region and play an important role in MHV-68 lytic DNA replication during de novo infection.
Animals ; Base Sequence ; CCAAT-Enhancer-Binding Proteins ; genetics ; metabolism ; Cell Line ; Chromatin Immunoprecipitation ; Cricetinae ; DNA Replication ; DNA, Viral ; chemistry ; genetics ; metabolism ; Electrophoretic Mobility Shift Assay ; Genome, Viral ; Herpesviridae Infections ; genetics ; metabolism ; virology ; Humans ; Mice ; Molecular Sequence Data ; Plasmids ; Promoter Regions, Genetic ; Protein Isoforms ; genetics ; metabolism ; Replication Origin ; Rhadinovirus ; genetics ; metabolism ; Viral Proteins ; genetics ; metabolism ; Virus Latency ; genetics

OBJECTIVETo explore the expression of origin recognition complex 1 (ORC1) during the DNA replication of vascular muscle cells (VSMC).

METHODSVSMC of thoracic aorta in rats were obtained by the adherence method of tissue culture. The cell synchrony was obtained by the method of double-thymidine block, colchicine treatment and serum starvation. The expression of ORC1 mRNA at different cell cycles of VSMC was determined by RT-PCR and the protein expression of ORC1 was analyzed by Western blot.

RESULTSCultured VSMC were identified by light microscope and immunocytochemistry. Significant expression of ORC1 mRNA and protein in a quiescent stage of VSMC were not observed. Upon synchronization, the expression of ORC1 mRNA was significantly higher at G(1)/S phase of VSMC than that at S and G(2)/M phases. The expression of ORC1 protein followed same changes as the ORC1 mRNA expression at different stages of cell cycles.

CONCLUSIONORC1 may be an important regulatory factor at the initiation of proliferative process of VSMC.

Animals ; Aorta, Thoracic ; cytology ; Blotting, Western ; Cell Cycle ; Cell Proliferation ; Cells, Cultured ; DNA ; genetics ; DNA Replication ; Gene Expression Regulation, Neoplastic ; Male ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; metabolism ; Origin Recognition Complex ; biosynthesis ; genetics ; physiology ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction