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:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability to induce proliferation by temporary duct ligation suggested an hypothesis that retrovirus-mediated gene transfer into cells of the biliary tract could be accomplished. The time course of histologic changes, incorporation of 3H-thymidine and immunofluorescent staining with a monoclonal antibody to cytokeratin-19 (a marker for differentiated bile ducts) was studied in male Fischer F344 rats. A recombinant Gibbon ape leukemia virus (GALV), containing a gene encoding Escherichia coli beta-galactosidase was next introduced into 24 hr obstructed bile ducts. Gene transfer was maximal when virus was exposed to the obstructed duct for 12 hr (approximately 0.1%). The majority of X-gal positive cells were in cytokeratin-19 negative peribiliary tissues, which had the appearance of newly forming bile ducts. The data suggest that cells targeted by retroviral infection of the obstructed rat bile duct may be a precursor of mature, fully differentiated biliary epithelium.
...
PMID:Targeted retroviral gene transfer into the rat biliary tract. 864 91

Deficiency in p53-mediated cell death is common in human cancer, contributing to both tumorigenesis and chemoresistance. In an attempt to restore p53, we evaluated in vitro infectivity and cytotoxicity of a wild type (w.t.) p53-expressing adenovirus (Ad-p53) toward a panel of human cancer cell lines (n = 19). At a multiplicity of infection of 30, both Ad-p53 and adenovirus expressing beta-galactosidase (Ad-LacZ) infected greater than 99% of cells derived from brain, lung, breast, ovarian, colon, and prostate cancer, but failed to infect leukemia or lymphoma cells. Ad-p53, but not Ad-LacZ, infection of cancer cells was followed by nuclear accumulation of the CDK inhibitor p21WAFI/CIPI, cell cycle arrest and loss of viability. Ad-p53 induced apoptotic death in cancer cells that express mutant p53, including multi-drug resistant cells, but fewer deaths were observed in some w.t. p53 expressing cells. Ad-p53-infected SKBr3 breast cancer cells were more sensitive to cytotoxicity of the DNA damaging drugs mitomycin C or Adriamycin, but not the M-phase specific drug vincristine. Our results suggest that Ad-p53 is capable of infecting and killing cancer cells of diverse tissue origins (including multi-drug resistant cancer cells), that p21WAFI/CIPI may be a useful marker of p53 infectivity and that there may be synergy between Ad-p53 and either mitomycin C or Adriamycin induced cell death in tumors with p53 mutations.
...
PMID:In vitro evaluation of a p53-expressing adenovirus as an anti-cancer drug. 870 13

As a result of its capacity to establish and maintain a life-long latent infection in the nervous system, herpes simplex virus (HSV) has been promoted as an ideal vector for introducing DNA into mature, differentiated, post-mitotic neurons. Although delivery of foreign genes into neurons using HSV vectors has been well established, the potential of these vectors for scientific inquiry or therapeutic use has been hampered by the lack of efficient long-term expression of these foreign genes. In the few instances where expression from the latent genome has been reported, expression appears to be minimal and levels of mRNA present have not been established. Here we describe HSV viral vectors that express a foreign gene during latency in dorsal root ganglia (DRG). More particularly, we have constructed a vector that, by histochemical assays for the protein, expresses the beta-galactosidase (beta-Gal) gene for at least 18 months post infection. We have further characterized the expression of beta-Gal transcripts by quantitative reverse transcription polymerase chain reaction (RT-PCR) and determined that there are 32,000 copies of beta-Gal transcripts per 0.5 microgram of total RNA at 18 months post infection. The vector makes use of the mouse Moloney leukemia virus (MMLV) long terminal repeat (LTR) promoter located directly upstream from the latency-associated transcripts (LAT) promoter region and expresses mRNA from the DNA strand opposite to that expressing the LAT. Finally, the vector was constructed using a system that allows other promoter/gene constructs to be easily inserted into the viral genome. It may have utility in studying the effects of cellular or viral gene expression on establishment, maintenance or reactivation from latency or for the delivery and expression of therapeutic proteins employed in gene therapy of the nervous system.
...
PMID:Long-term expression of a foreign gene from a unique position in the latent herpes simplex virus genome. 884 4

The hamster polyomavirus (HaPV) is associated with spontaneously appearing skin epithelioma of the Syrian hamster Z3 strain. Virus particles prepared from the skin epithelioma cause lymphoma and leukemia when injected into newborn hamsters from a distinct Syrian hamster colony (HaP); in contrast to the skin epithelioma the hemopoietic tumors are virus free but accumulate viral DNA. To study the humoral immune response of HaPV-infected Z3 hamsters we produced recombinant HaPV proteins in Escherichia coli as beta-galactosidase-, TrpE- and dihydrofolate reductase-fusion proteins or as non-fused proteins. Recombinant plasmids carried segments of all putative early and late HaPV proteins. The recombinant proteins were detected in stained SDS polyacrylamide gels and in Western blots using monoclonal anti-TrpE and anti-beta-galactosidase antibodies and sera of HaPV-infected hamsters. Sera from HaPV-infected Z3 hamsters and crude lysates of all clones were applied to Western blots to characterize the humoral immune response in the animals. HaPV-specific antibodies were found to be directed against early protein segments translated from the first common exon and from the second unique exon of LT and MT, resp., as well as against the late proteins VP1 and VP2/3. The almost complete VP2 was recognized by all sera whereas VP1 was detected only by a half of the sera. Our data suggest the presence of at least 2 immunodominant regions in VP2, one in the C-terminal VP1 and at least 4 in early proteins.
...
PMID:Hamster polyomavirus-encoded proteins: gene cloning, heterologous expression and immunoreactivity. 888 64

The transcription factor Tax of the oncogenic human T-cell leukemia virus type 1 is likely to be responsible for viral replication in the host organism and for the induction of proliferation in infected cells. To investigate Tax-mediated transcription in vivo, we expressed Tax as well as CREB in Saccharomyces cerevisiae. The activity of these proteins was monitored by expression of a beta-galactosidase reporter gene, which was fused to two viral 21-bp repeats located upstream of the yeast cytochrome c1 oxidase minimal promoter. Coexpression of Tax and CREB in S. cerevisiae led to a 20-fold increase in beta-galactosidase activity in comparison with that in strains expressing either Tax or CREB alone. By screening a human cDNA library, we were able to demonstrate that the Tax transactivation assay using S. cerevisiae can be successfully applied to identify other cellular proteins forming ternary complexes with Tax and 21-bp repeats in vivo. Upon transformation in S. cerevisiae, 1 of 13,500 clones tested positive. Sequencing of the cDNA insert of the rescued plasmid revealed that this DNA encoded the ATF-1 protein. beta-Galactosidase induction was comparable to that of the Tax/CREB coexpression system. This indicates that Tax-mediated transcription is critically dependent on the presence of cellular CREB or ATF-1 in vivo. Stimulation of transcription initiation required an unmasked NH2 terminus of Tax. Fusion of Tax to the yeast Gal4 protein abolished the transactivation potential of Tax. Reconstitution of the transcriptional properties of viral Tax together with the cellular proteins of the ATF-1/CREB family in S. cerevisiae allows the functional characterization of these proteins in vivo.
...
PMID:The oncoprotein Tax of the human T-cell leukemia virus type 1 activates transcription via interaction with cellular ATF-1/CREB factors in Saccharomyces cerevisiae. 889 66

A new class of retroviral vector pseudotypes have an expanded host species range and can be concentrated to high titers by ultracentrifugation. These pantropic vectors contain the genome of the murine leukemia virus-based vectors and the envelope protein of vesicular stomatitis virus substituted for the amphotropic envelope protein. We tested (a) the ability of pseudotyped (pantropic) and unmodified (amphotropic) vectors to stably infect three different Xenopus laevis cell lines, including one derived from the embryonic retina; and (b) the ability of the concentrated pseudotyped virus to infect embryos and to mediate foreign gene expression in the embryonic CNS. Expression of the neomycin phosphotransferase gene and single copy integration of the provirus into the genome of the cell lines was demonstrated. Surprisingly, the amphotropic and pantropic vectors generated neomycin-resistant clones with similar efficiency. PCR amplification of genomic DNA from single stage 10, 20, and 25 embryos microinjected in the blastocoel or neural tube cavities with concentrated pantropic vector (10(8) cfu/ml) revealed proviral DNA. Microinjection of a concentrated pantropic vector containing the coding sequence for the beta-galactosidase gene into the neural tube lumen of 24-h embryos yielded beta-galactosidase expressing cells in the brain. Thus, retroviral vectors provide an additional approach to existing strategies for gene transfer in Xenopus embryos and cell lines.
...
PMID:Retrovirol gene transfer in Xenopus cell lines and embryos. 890 20

We generated several lines of mice transgenic for the lacZ reporter gene under the control of an HTLV-I LTR. Two different LTR were used; one was isolated from a case of Adult T-cell Leukemia (ATL), the other from a case of Tropical Spastic Paraparesis (TSP/HAM). These LTR differed at 18 nucleotide positions. The pattern of expression of the transgene, studied at the RNA level by RT-PCR, was the same regardless of the origin of the promoter. The beta-galactosidase activity was detected primarily in the central nervous system, in the parenchyma, the choroid plexus and the ependymal cells along the ventricles. In parenchyma, double labelling experiments showed that the cells expressing beta-galactosidase were neurons. These results show that choroid plexus cells and ependymal cells, as well as some neurons, are permissive for the activity of the HTLV-I promoter. The origin of the LTR had not influence on the pattern of expression of the reporter gene.
...
PMID:Analysis of the expression directed by two HTLV-I promoters in transgenic mice. 902 6

Contractile events resulting from phosphorylation of the 20-kDa myosin light chain (MLC20) have been implicated in the regulation of epithelial tight junction permeability. To address this question, Madin-Darby canine kidney cells were transfected with a murine leukemia retroviral vector containing DNA encoding either the catalytic domain of myosin light chain kinase (tMK) or the beta-galactosidase gene (beta-gal). Autoradiograms of sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of myosin immunoprecipitated from 32Pi-labeled transfected cells demonstrated that MLC20 phosphorylation was increased 3.1 +/- 0.9-fold in cells expressing tMK compared with cells expressing beta-gal. Phosphopeptide mapping confirmed that myosin light chain kinase was responsible for the increased MLC20 phosphorylation. Transepithelial electrical resistance, a measurement of barrier function, of tMK cell monolayers was consistently < 10% (123 +/- 20 omega.cm2) of that of monolayers comprised of wild-type cells (1,456 +/- 178 omega.cm2) or cells expressing beta-gal (1,452 +/- 174 omega.cm2). Dual 22Na+ and [3H]mannitol flux studies indicated that the decrease in resistance in tMK cells was attributable to increased paracellular flow. These data support the idea that MLC20 phosphorylation by myosin light chain kinase is involved in regulating epithelial tight junction permeability.
...
PMID:Expression of the catalytic domain of myosin light chain kinase increases paracellular permeability. 894 52

Adenovirus vectors have several features that make them attractive for potential use in gene therapy, including a broad tissue tropism and an ability to infect quiescent or postmitotic cells. In light of this, we examined whether recombinant adenovirus vectors could transfer genes into neoplastic cells of patients with chronic lymphocytic leukemia (CLL), a leukemia of "resting" B cells. Using high-titer recombinant adenovirus vectors, we found we could transfer genes encoding beta-galactosidase or murine CD80 (B7-1) into the CLL B cells of all patients tested (n = 10). The efficiency of gene transduction into CLL B cells was approximately 100 to 1,000-fold lower than into HeLa cells at any given multiplicity of infection (MOI). At a MOI of 500, 10% to 70% of the CLL B cells from different patients were made to express the transgene, as assessed by multiparameter flow cytometric analysis. Sustained levels of expression with little loss in the percentage of infected cells were maintained for up to 9 days, at which point the analysis was stopped. We found that CLL B cells have markedly lower expression levels of integrins that facilitate internalization of adenovirus particles into target cells, perhaps accounting, in part, for the reduced efficiency of adenovirus-mediated gene transfer compared with that in HeLa cells. Although HeLa cells express high levels of alpha(v)beta5, and detectable amounts of alpha(v)beta3, we find CLL cells from all patients tested express only low amounts of alpha(v)beta3, and no detectable alpha(v)beta5. Activation of CLL cells via CD40 cross-linking enhances expression of alpha(v)beta3, and induces expression of alpha(v)beta5. This phenotypic change is associated with a fivefold increase in the efficiency of adenovirus-mediated gene transfer into such activated CLL B cells. This study demonstrates that adenovirus vectors can transduce genes into CLL B cells and that the efficiency of gene transduction is enhanced by activation via CD40 cross-linking. This is the first demonstration that high proportions of CLL B cells can be made to express a selected transgene, suggesting that such gene transfer methods may become useful for the study of the pathogenesis and/or treatment of this disease.
...
PMID:Adenovirus vector infection of chronic lymphocytic leukemia B cells. 897 61

A retroviral packaging transcription unit was constructed in which the Moloney murine leukemia virus (MoMLV) gag-pol and env genes are expressed under the control of herpesvirus regulatory sequences. This transcription unit, lacking long terminal repeats, primer binding sites, and most of the retrovirus packaging signal but retaining both retroviral donor and acceptor splice sites, was cloned into a herpes simplex virus type 1 (HSV-1) amplicon plasmid, and amplicon vectors (the gag-pol-env [GPE] vectors) were generated by using a defective HSV-1 vector as helper virus. The GPE vector population was used to infect human TE671 cells (ATCC CRL 8805), harboring a lacZ provirus (TE-lac2 cells), and supernatants of infected cells were collected and filtered at different times after infection. These supernatants were found to contain infectious ecotropic lacZ retroviral particles, as shown both by reverse transcription-PCR and by their ability to transduce a beta-galactosidase activity to murine NIH 3T3 cells but not to human TE671 cells. The titer of retroviral vectors released by GPE vector-infected TE-lac2 cells increased with the dose of infectious amplicon particles. Retrovirus vector production was inhibited by superinfection with helper virus, indicating that helper virus coinfection negatively interfered with retrovirus production. Induction of retrovirus vectors by GPE vectors was neutralized by anti-HSV-1 but not by anti-MoMLV antiserum, while transduction of beta-galactosidase activity to NIH 3T3 cells by supernatants of GPE vector-infected TE-lac2 cells was neutralized by anti-MoMLV antiserum. These results demonstrate that HSV-1 GPE amplicon vectors can rescue defective lacZ retrovirus vectors and suggest that they could be used as a sort of launching ramp to fire defective retrovirus vectors from within virtually any in vitro or in vivo cell type containing defective retroviral vectors.
...
PMID:Defective herpes simplex virus type 1 vectors harboring gag, pol, and env genes can be used to rescue defective retrovirus vectors. 909 92


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---