Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.1.21 (thymidine kinase)
7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The env and gag genes from feline leukaemia virus were expressed in a thymidine kinase-negative feline herpes-virus and a baculovirus. Cats were vaccinated with various combinations of these recombinant viruses and 100% protection against feline leukaemia virus challenge was achieved using an immunization schedule which utilized both env and gag products delivered at both a mucosal and systemic site.
...
PMID:The use of feline herpesvirus and baculovirus as vaccine vectors for the gag and env genes of feline leukaemia virus. 132 Dec 14

Chimeric plasmids in which the herpes thymidine kinase (tk) gene replaced portions of the Rous sarcoma viral genome were used to assess the relationship between viral transcription and that of an exogenous gene located within the viral genome. The entire tk gene and portions of the gene were positioned in both orientations within the viral gag and pol genomic region (which serves as intron for viral env mRNA). Microinjection assays then determined the amount of viral genomic transcription by quantitation of the amount of viral env mRNA produced. Separate injections also assayed for the presence of tk mRNA. Both mRNAs were produced unless the 3' region of the tk gene was present within the viral genome and in the same transcriptional sense. In this case viral env mRNA production was nearly abolished.
...
PMID:The effects of transcriptional regulatory sequences introduced into a retroviral genome. 301 46

The mammary gland specific, glucocorticoid controlled expression of MMTV makes it an ideal candidate for the basis of a nonpromiscuous regulated retroviral vector system. We have previously constructed an MMTV proviral variant that gives rise to virus particles upon introduction into cultured cells. This was used to construct a defective MMTV provirus in which the MMTV env gene was replaced by the neomycin resistance gene under the control of the herpes simplex thymidine kinase promotor. The defective provirus was packaged after transfection into two distinct MMTV producing cell lines. Conditioned medium from these cells contains virus particles which are able to infect cells of fibroblast and epithelial origin and to confer neomycin resistance upon them. This indicates that the defective MMTV provirus contains the sequences required for packaging of the genomic viral RNA. Transfection of the same MMTV-neo recombinant provirus into the MoMLV packaging cell line, psi 2, did not result in any infectious virus particles. Thus the packaging signals for MMTV and MoMLV appear to be distinct. Analysis of the MMTV infected cells reveals the presence of the MMTV-neo recombinant provirus. Expression of both MMTV and neomycin is detectable and augmented when the infected cells are grown in the presence of glucocorticoid hormone.
...
PMID:Mouse mammary tumor virus mediated transfer and expression of neomycin resistance to infected cultured cells. 302 73

A series of deletions and insertions utilizing the herpesvirus thymidine kinase gene (tk) were constructed in the murine retrovirus Friend spleen focus-forming virus (SFFV). In all cases, the coding region for the SFFV-specific glycoprotein (gp55), which is implicated in erythroleukemic transformation, was left intact. These SFFV-TK and SFFV deletion vectors were analyzed for expression of tk and gp55 after DNA-mediated gene transfer. In addition, virus rescued by cotransfection of these vectors with Moloney murine leukemia virus was analyzed for infectious TK-transducing virus, gp55 expression, and erythroleukemia-inducing ability. The experiments demonstrated that deletions or insertions within the intron for the gp55 env gene can interfere with expression of gp55 after both DNA-mediated gene transfer and virus infection. In contrast, the gene transfer efficiency of the tk gene was unaffected in the SFFV-TK vectors, and high-titer infectious TK virus could be recovered. Revertant viruses capable of inducing erythroleukemia and expressing gp55 were generated after cotransfection of the SFFV-TK vectors with murine leukemia virus. The revertant viruses lost both tk sequences and the ability to transduce TK- fibroblasts to a TK+ phenotype. These experiments demonstrate that segregation of the TK and erythroleukemia functions can occur in retrovirus vectors which initially carry both markers.
...
PMID:Retrovirus transduction: segregation of the viral transforming function and the herpes simplex virus tk gene in infectious Friend spleen focus-forming virus thymidine kinase vectors. 631 88

We wished to construct cell lines that supply the gene products of gag, pol, and env for the growth of replication-defective reticuloendotheliosis retrovirus vectors without production of the helper virus. To do this, first we located by S1 mapping the donor and acceptor splice sites of reticuloendotheliosis virus strain A. The donor splice site is ca. 850 base pairs from the 5' end of proviral DNA. It is close to or overlaps the encapsidation sequences for viral RNA. The splice acceptor site is ca. 5.6 kilobase pairs from the 5' end of proviral DNA. Therefore, the encapsidation sequences and the donor splice site were removed from viral DNA to give expression of the gag and pol genes without virus production. The promoter in the long terminal repeat was fused to a site near the first ATG codon of the env gene, thereby deleting the encapsidation sequences and the gag and pol genes to give expression of the env gene without virus production. The permissive canine cell line D17 was transfected with the two modified viral DNAs. Two cell clones that contain both modified viral DNAs support the production of replication-defective spleen necrosis virus-thymidine kinase recombinant retrovirus vectors without the production of helper virus. To prevent recombination, the vector contains deletions that overlap with deletions in the integrated helper virus DNAs. This helper cell-vector system will be useful to derive infectious recombinant virus stocks of high titer (over 10(5) thymidine kinase transforming units per ml) which are able to infect avian, rat, and dog cells without the aid of helper virus.
...
PMID:Construction of a helper cell line for avian reticuloendotheliosis virus cloning vectors. 631 91

This work was aimed at generating a novel system for gene transfer to tumor cell, combining the advantages of non-viral gene transfer methods with those of transfer by recombinant retroviruses. We replaced the env gene of an infectious Moloney murine leukemia provirus with the gene coding for the thymidine kinase of Herpes Simplex Virus 1 (HSV1-TK). The sole transfection of this construction allows the production of viral particles, and the encapsidation of a viral genome carrying transgene. We show that this gene is expressed at a level sufficient for conferring sensitivity to ganciclovir, a nucleoside analog that is metabolised in a toxic compound by HSV1-TK. We also show that the complementation of this recombinant defective provirus with a gene coding for a retroviral envelope, either expressed constitutively by the transduced cell, or by co-transfection, leads to the formation of infectious viral particles capable of transducing HSV1-TK into tumor cells.
...
PMID:[Generation of a trans-complementable defective recombinant provirus and loading a transgene]. 867 19

Adult T cell leukemia/lymphoma (ATL) is derived from CD4+ T cells and has a poor prognosis because of its resistance to chemotherapy. To evaluate the effectiveness of gene therapy for ATL, the effect of ganciclovir on ATL cell lines transfected with the thymidine kinase gene of herpes simplex virus type 1 (HSV-TK) was analyzed. To transfer the HSV-TK gene to ATL cells, a human immunodeficiency virus (HIV) vector that has specific infectivity to CD4+ cells was used. HSV-TK was inserted into the long terminal repeats of HIV-1 and driven by the SL3 promoter HXBSL3TK. HXBSL3TK was co-transfected with HXBCAT as a reporter into MT2 or HUT102 cells by DEAE-dextran. The cells were incubated with ganciclovir, and chloramphenicol acetyltransferase (CAT) activity was analyzed. The CAT activity of the MT2 cells and HUT102 cells transfected with HXBSL3TK decreased dose-dependently with ganciclovir. HXBSL3TK was also co-transfected into COS cells with an HIV-1 packaging vector that has gag, pol, and env driven by a cytomegalovirus promoter. The supernatant was transferred to MT2 cells or Raji cells and incubated with ganciclovir. Ninety percent of the MT2 cells transduced by HXBSL3TK and incubated with ganciclovir were killed, but Raji cells were not killed. In addition, HXBTK that expresses the HSV-TK gene and Tat gene driven by the LTR of HIV-1 was constructed. HXBTK had a higher expression of the HSV-TK gene and higher sensitivity to ganciclovir than did HXBSL3TK.
...
PMID:Gene therapy for adult T cell leukemia using human immunodeficiency virus vector carrying the thymidine kinase gene of herpes simplex virus type 1. 895 10

We mapped the canarypox virus (CaPV) thymidine kinase (TK) gene within a 5.8-kbp XbaI fragment of the genome by Southern blotting using the fowlpox virus (FPV) TK gene as a probe. Nucleotide sequence analysis of the fragment revealed seven open reading frames (ORFs) showing gene organization similar to that of FPV. The TK gene contained in this region had an ORF of 179 amino acids encoding a polypeptide with a putative molecular mass of 20.0 kDa. An A/T-rich region and a transcription termination signal, TTTTTAT, were found upstream and at the end of the ORF, which is consistent with poxvirus early gene regulation. The consensus sequence of the late promoter TAAAT also overlapped with the initiation codon of the ORF. The amino acid sequence similarity between the TK genes of CaPV and FPV, avipoxviruses, was 64.2%, which was lower than the similarities between vaccinia and variola orthopoxviruses (97.2%) and between Shope fibroma and myxoma leporipoxviruses (82.6%). However, the monophyly of avian clades of CaPV and FPV was supported by phylogenetic analysis. We then inserted the genes encoding lacZ, luciferase (luci), and envelope of human T-lymphotropic virus type 1 (HTLV-1 env) into the TK gene of CaPV to evaluate its suitability as an expression vector. The recombinant viruses obtained were unstable, although the foreign genes were expressed efficiently in the mammalian cells infected with the viruses.
...
PMID:Identification of the canarypox virus thymidine kinase gene and insertion of foreign genes. 1019 Nov 93

We constructed two recombinant feline herpesvirus type 1 (FHV-1) expressing the envelope (Env) protein of feline immunodeficiency virus (FIV). One recombinant, designated dlTK-env, has the whole FIV env gene inserted at a thymidine kinase (TK) deletion site. The second recombinant, designated dlTK(gCp)-env, has a cassette containing a partial FIV env gene fused with the signal sequence of the gC protein of FHV-1 (under the control of the gC promoter) inserted at the same site. Growth kinetics of both the recombinants in Crandell feline kidney (CRFK) cells were similar to that of the parent strain of FHV-1. By indirect immunofluorescence assays and immunoblot analyses, we confirmed the expression of the FIV Env protein in CRFK cells infected with both recombinants. Enzyme-linked immunosorbent assays showed that the maximum Env expression level achieved by dlTK(gCp)-env was more than four times higher than that observed for dlTK-env. Flow cytometric analyses revealed that the Env protein produced by both recombinants was efficiently expressed on the cell surface. The dlTK(gCp)-env reported here may thus be a promising candidate for a live recombinant vaccine to protect against FIV infection.
...
PMID:Efficient expression of the envelope protein of feline immunodeficiency virus in a recombinant feline herpesvirus type 1 (FHV-1) using the gC promoter of FHV-1. 1107 21

Oka varicella vaccine has been used to confer active immunity to varicella-zoster virus (VZV) in healthy and immunocompromised hosts. Based on its attenuated nature, Oka varicella vaccine expressing human immunodeficiency virus (HIV) env antigen was constructed by inserting the HIVenv gene into the viral genome and its immunogenicity was assessed in guinea pigs. The HIVenv gene encoding 296-463 amino acids was inserted between the sequences of the hepatitis B surface antigen and the thymidine kinase gene of the cloned plasmid and the recombinant virus was isolated by cotransfection of the chimeric plasmid with viral DNA. Insertion of the HIVenv gene into the viral genome was confirmed by PCR and sequencing of the viral genome of the recombinant virus. The recombinant virus expressed 30k HIVenv fusion protein in its infected cells. In guinea pigs, immunization with the recombinant virus induced an antibody response to both the HIV antigen and the V3 peptide of gp120 as well as VZV gE:gI. Cell-mediated immunity to the HIV antigen and gE:gI was assessed by the cutaneous reaction representing delayed type hypersensitivity. Immunized guinea pigs responded well to both the HIV antigen and gE:gI. Thus the recombinant Oka varicella vaccine expressing the HIVenv antigen induced both a humoral and cell-mediated immunity to the HIV antigen similar to VZV as Oka varicella vaccine induces humoral and cell-mediated immunity to VZV in the vaccinees. This recombinant Oka varicella vaccine expressing the HIVenv antigen may be evaluated for its immunogenicity as one of the AIDS vaccine candidates.
...
PMID:Construction of Oka varicella vaccine expressing human immunodeficiency virus env antigen. 1136 Feb 39


1 2 Next >>

---