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)

We have designed a system in which to test gene transfer into gut neurons consisting of an organ culture of neonatal rat small intestine. The tissue was exposed to herpes simplex- and adenovirus-derived vectors: (1) a temperature-sensitive herpes simplex virus-1 (HSV1) vector (tsK-beta gal) containing the lacZ gene encoding beta-galactosidase (beta-gal), under the transcriptional control of the HSV1 immediate-early 3 (IE3) promoter; (2) RAd35, an E1-/E3- replication-deficient adenovirus expressing lacZ under the control of a truncated HCMV major IE promoter; and (3) RAd122, an E1-/E3- replication-deficient adenovirus expressing the lacZ under the control of the RSV LTR. Forty-eight hours after the vector was added to the organ culture, we detected beta-gal using immunohistochemistry or X-gal histochemistry in tissue sections examined by light microscopy. We encountered a distinctive staining of cells arranged in two concentric circles corresponding in location to the myenteric and submucosal plexuses. Cells in these areas were of similar size and morphology to neonatal enteric neurons, as visualized by NADPH-diaphorase histochemistry and immunocytochemical staining with antibodies to the neuronally expressed proteins PGP 9.5, or neurofilaments. Double labelling with antibodies recognizing neurofilaments and beta-galactosidase revealed that most cells infected by tsK were neurons, while the RAd35 and 122 vectors only infected non-neuronal cells. We thus demonstrate that both HSV1- and adenovirus-derived vectors can be used to transfer genes to the gut in vitro, but they transduce different populations of target cells.
...
PMID:Gene transfer into enteric neurons of the rat small intestine in organ culture using a replication defective recombinant herpes simplex virus type 1 (HSV1) vector, but not recombinant adenovirus vectors. 917 19

The tissue kallikrein-kinin system has been postulated to play a role in blood pressure homeostasis and the pathogenesis of clinical hypertension. To demonstrate the potential therapeutic effects of somatic gene delivery in treating hypertension, we used spontaneously hypertensive rats (SHR) as a model. The gene encoding the human tissue kallikrein was used because of its powerful hypotensive action. The human kallikrein DNA constructs were placed under the control of the metallothionein metal response element, the cytomegalovirus promoter/enhancer or the Rous sarcoma virus 3'-LTR. The human tissue kallikrein DNA constructs were incorporated into adenoviral vectors via homologous recombination. The naked plasmid DNA constructs or adenovirus containing the kallikrein gene were first introduced into kidney 293 cells and the expression of human tissue kallikrein was identified by ELISA. The kallikrein gene was delivered into SHR via intramuscular, intravenous, portal vein, intraperitoneal, and intracerebroventricular routes. A single injection of naked human kallikrein DNA constructs caused a prolonged reduction of high blood pressure for up to 8 weeks. Adenoviral-mediated gene delivery results in high efficiency of human tissue kallikrein expression. Immunoreactive human kallikrein was detected in rat serum at the highest level at 1 day post gene delivery. Portal vein delivery of a reporter gene, AdCMV-LacZ, results in intense staining of beta-galactosidase in rat liver, suggesting that recombinant kallikrein is mainly produced in liver and secreted into the circulation. These results show that kallikrein gene delivery causes a sustained reduction of blood pressure in genetically hypertensive rats and provide important information for a potential gene therapy approach to human hypertension and related diseases.
...
PMID:Kallikrein gene therapy: a new strategy for hypertensive diseases. 922 51

I. Benhar and H. Engelberg-Kulka reported that a 55 nucleotide translational bypass occurs in decoding a fusion of the Escherichia coli tryptophan repressor, trpR, and lacZ genes. The start of the bypass occurred in the trpR gene and coding resumed in the lacZ gene. It was considered that bypassing likely occurred in expression of trpR itself to produce an additional 10 kDa product which may be biologically important. We report here that bypass is undetectable in the same and related trpR'-lacZ' fusions. The beta-galactosidase activity derived from the fusions is accounted for by unusual internal initiation and +1 frameshifting, both of which occur in the lacZ part of the fusion. The 10 kDa product reportedly encoded by the trpR gene was not detectable to a level of 1% of the full-length 12 kDa tryptophan repressor product, at least when expressed from a T7 promoter.
...
PMID:Reported translational bypass in a trpR'-lacZ' fusion is accounted for by unusual initiation and +1 frameshifting. 928 21

Ballistic transfection, based on cell and tissue bombardment by the tungsten and gold microparticles covered with the gene DNA, was used for the delivery of a bacterial beta-galactosidase and a full-length cDNA copy of the human dystrophin genes into mouse skeletal muscles. CMV-lacZ, SV40-lacZ, LTR-lacZneo and full-length cDNA dystrophin (pDMD-1, approximately 16 kb) in eukaryotic expression vector pJ OMEGA driven by mouse leukaemia virus promotor (pMLVDy) were used throughout the studies. Musculus glutaeus superficialis of C57BL/6J and quadriceps femoris of mdx male mice were opened surgically under anesthesia and bombarded by means of the gene-gun technique originally developed by us. Different mixtures of gold and tungsten particles at ratios of 4:1, 1:1, 1:4 were applied. X-gal assay revealed marked beta-gal activity, both in total muscles and whole muscle fibers on histological sections, up to three months after transfection. The most intensive staining was observed after SV40-lacZ delivery. No staining was detected with LTR-lacZneo DNA as well as in untreated muscles. The higher tungsten particle concentration in the bombardment mixture correlated with more intense X-gal staining. At the gold/tungsten ratio of 1:4 the microparticles penetrated the musculus glutaeus superficialis and transfected the underlying musculus glutaeus medius as well. Immuno-cytochemical assay for human dystrophin revealed dystrophin positive myofibers (DPM) in the bombarded area up to two months after transfection. The proportion of DMP varied from 2.5% on day 17 up two 5% on day 60 after bombardment compared to only 0.5% in the control mdx mice. These results suggest the applicability of particle bombardment for gene delivery into muscle fibers.
...
PMID:Bacterial beta-galactosidase and human dystrophin genes are expressed in mouse skeletal muscle fibers after ballistic transfection. 931 10

The human aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator protein (ARNT) were coexpressed in the yeast Saccharomyces cerevisiae to create a system for the study of this heterodimeric transcription factor. Specific transcriptional activation mediated by AHR/ARNT heterodimer, which is a functional indicator of receptor expression, was assessed by beta-galactosidase activity produced from a reporter plasmid. Yeast expressing AHR and ARNT displayed constitutive transcriptional activity that was not augmented by addition of AHR agonists in strains that required exogenous tryptophan for viability. In contrast, strains with an intact pathway for tryptophan biosynthesis responded to AHR agonists and had lower levels of background beta-galactosidase activity. Hexachlorobenzene, benzo(a)pyrene, and beta-naphthoflavone were effective AHR agonists in the yeast system, and had EC50 values of 200, 40, and 20 nM, respectively, for beta-galactosidase activity induction. Tryptophan, indole, indole acetic acid, and tryptamine activated transcription in yeast coexpressing AHR and ARNT (EC50 values approximately 300 microM). Indole-3-carbinol was an exceptionally potent AHR agonist (EC50 approximately 10 microM) in yeast. This yeast system is useful for the study of AHR/ARNT protein complexes, and may be generally applicable to the investigation of other multiprotein complexes.
...
PMID:Expression of the human aryl hydrocarbon receptor complex in yeast. Activation of transcription by indole compounds. 940 59

The efficient genetic modification of solid tumors in situ to stimulate therapeutic immune responses against them is currently under active investigation, but is not yet possible using existing gene transfer technologies. Thus, ex vivo/in vivo vaccination strategies have been proposed in which the patient's tumor is surgically excised, single cell suspensions are prepared, the therapeutic genes are introduced and then the gene-modified cells, after being gamma-irradiated, are injected back into the patient. However, even with high-efficiency gene delivery systems, this is a labor-intensive process. Moreover, it is often difficult to obtain sufficient numbers of gene-modified primary tumor cells during short-term culturing. On the other hand, extended in vitro passaging of primary tumor explants may alter their immunophenotypic properties. One approach to overcome these limitations would be to design universal vaccines consisting of standardized gene-transduced neoplastic cell lines or mixtures of gene-transduced cell lines to be combined with autologous tumor samples if available. Melanoma, which is notable for being one of the most immunogenic human malignancies, represents a cancer where shared tumor-associated antigens have been identified. We developed and analyzed several different retroviral vectors for their ability to stably express exogenous genes at high levels in a panel of melanoma cell lines. All vectors contained a reporter gene (nlslacZ) encoding beta-galactosidase with a nuclear localization signal and the neomycin phosphotransferase (neo) gene as selectable marker. One vector, DCCMV, which carried a bicistronic nlslacZ-neo transcriptional unit under the control of the human cytomegalovirus immediate-early promoter in the U3 region of its 3' LTR, was found to perform consistently better than the other vectors. The DCCMV vector, which is an extreme example of the double-copy class of retroviral vectors, was subsequently used to generate melanoma cell lines constitutively secreting human interleukin-6 or a soluble form of the human interleukin-6 receptor for potential use in a phase II clinical vaccine trial for the treatment of melanoma patients. The DCCMV vector design may also be useful in gene therapy applications where the intent is to implant polymer-encapsulated cell lines genetically engineered to stably express high levels of bioactive proteins.
...
PMID:Double-copy bicistronic retroviral vector platform for gene therapy and tissue engineering: application to melanoma vaccine development. 941 12

The conformational changes in dimeric Kluyveromyces lactis beta-galactosidase induced by hydrostatic pressure were investigated by means of its intrinsic tryptophan fluorescence. At high pressure, the fluorescence emission spectrum was shifted to the red, indicating the exposure of buried Trp residues to the aqueous solvent. This spectral change was paralleled by a loss of enzyme activity. The shift of the emission spectrum was quantified by evaluating the centre of spectral mass ((nu(g))), which is an intensity-weighted mean wavenumber. The experimental data could be fitted to a two-state transition (native<-->denatured), corrected for a linear pressure dependence of (nu(g)), and allowed the determination of thermodynamic parameters deltaG0(app), V(app) and P(1/2). The results were consistent with a partial unfolding of the protein and not simply with dissociation of this dimeric enzyme. In the presence of polyols, the native conformation of beta-galactosidase was considerably more resistant to pressure. This protective effect of polyols is probably due to a reduced accessibility of water inside the protein structure, through the direct or indirect action of these additives on the enzyme.
...
PMID:Influence of polyols on the structural properties of Kluyveromyces lactis beta-galactosidase under high hydrostatic pressure. 969 20

Analysis of the expression of a number of known genes in cultured human cells has revealed UVB-induced changes that may be specific for melanocytic cells. The response of c-fos, p53 and HIV-LTR reporter constructs to UVB and UVC was reduced in MM96L melanoma cells compared to HeLa. Cell cycle arrest produced by UVA, gamma radiation, cisplatin or the antimetabolite deoxyinosine differed from that of UVB. Cell cycle analysis after multiple doses of UVB raised the possibility that UVB-induced pRb depletion could result in increased mutation and thus enhanced tumourigenesis of irradiated melanocytes in skin subjected to a defined pattern of UVB exposure. To extend the analysis of gene expression in cultured melanocytic cells to uncharacterised genes, promoter trap cell clones containing unknown genes 'tagged' by a beta-galactosidase reporter construct were generated from MM96L cells. Altered gene expression in clones treated with a panel of DNA-damaging agents was quantitated by measurement of beta-galactosidase activity. Of the clones containing 'tagged' endogenous promoters induced by UVB, 52% were induced only by UVB and not by other DNA-damaging agents (cisplatin, N-methyl-N-nitro-nitrsoguanidine, fotemustine). One third of the clones were also activated by TPA suggesting that general DNA damage responses involving PKC are activated less frequently than unique pathways of gene activation. Overall, 60% of the 50 clones that responded to the panel of agents were induced by only one of the agents, indicating that a high proportion of genes are induced by agent-specific mechanisms. In the long term, promoter trapping may allow the full repertoire of UVB-inducible genes to be characterised.
...
PMID:UVB-specific regulation of gene expression in human melanocytic cells: cell cycle effects and implication in the generation of melanoma. 992 Apr 26

The retroviral nucleocapsid (NC) protein contains highly conserved amino acid sequences (-Cys-X2-Cys-X4-His-X4-Cys-) designated retroviral (CCHC) Zn2+ fingers. The NC protein of murine leukemia viruses contains one NC Zn2+ finger and mutants that were competent in metal binding (CCCC and CCHH) packaged wild-type levels of full-length viral RNA but were not infectious. These studies were extended to human immunodeficiency virus type 1 (HIV-1), a virus with two NC Zn2+ fingers. Viruses with combinations of CCHC, CCCC, and CCHH Zn2+ fingers in each position of HIV-1 NC were characterized. Mutant particles contained the normal complement of processed viral proteins. Four mutants packaged roughly wild-type levels of genomic RNA, whereas the remaining mutants packaged reduced levels. Virions with mutated C-terminal position NC fingers were replication competent. One interesting mutant, containing a CCCC Zn2+ finger in the N-terminal position of NC, packaged wild-type levels of viral RNA and showed approximately 5% wild-type levels of infectivity when examined in CD4-expressing HeLa cells containing an HIV-1 LTR/beta-galactosidase construct. However, this particular mutant was replication defective in H9 cells; all other mutants were replication defective over the 8-week course of the assay. Two long terminal repeat viral DNA species could be detected in the CCCC mutant but not in any of the other replication-defective mutants. These studies show that the N-terminal Zn2+ finger position is more sensitive to alterations than the C-terminal position with respect to replication. Additionally, the retroviral (CCHC) NC Zn2+ finger is required for early infection processes. The evolutionary pressure to maintain CCHC NC Zn2+ fingers depends mainly on its function in infection processes, in addition to its function in genome packaging.
...
PMID:Strict conservation of the retroviral nucleocapsid protein zinc finger is strongly influenced by its role in viral infection processes: characterization of HIV-1 particles containing mutant nucleocapsid zinc-coordinating sequences. 1008 30

We have cloned the 5'-region of the murine N-methyl-d-aspartate (NMDA) receptor channel subunit NR2C (GluRepsilon3) gene and characterized the cis- and trans-activating regulatory elements responsible for its tissue specific activity. By using a native epsilon3-promoter/lacZ-construct & various 5'-deletion constructs, we compared beta-galactosidase expression in non-neuronal NIH3T3 cells and in neuronal epsilon3-gene-expressing HT-4 cells and show that large parts of the epsilon3 promoter are responsible for the repression of the epsilon3 gene in non-neuronal cells. Deletion of exon 1 sequences led to an enhancement of epsilon3 transcription, suggesting a role of the 5'-untranslated region in epsilon3 gene regulation. Sequence analysis of the promoter region revealed potential binding sites for the transcription factor Sp1, the murine fushi tarazu factor1 (FTZ-F1) homologues, embryonic LTR binding proteins (ELP1,2,3) and steroidogenic factor (SF-1), as well as for the chicken ovalbumin upstream promoter transcription-factor (COUP-TF). Electrophoretic mobility shift assays confirmed specific binding of Sp1, SF-1 and COUP-TFI. Whereas point mutation studies indicate that, in neuronal HT-4 cells, Sp1 is apparently not critically involved in basal epsilon3 gene transcription, SF1 is a positive regulator. This was evident from a selective enhancement of epsilon3-promoter-driven reporter gene expression upon cotransfection of an SF1-expression vector, which was reverted by deletion and point mutation of the SF1 binding site.
...
PMID:Regulation of the murine NMDA-receptor-subunit NR2C promoter by Sp1 and fushi tarazu factor1 (FTZ-F1) homologues. 1033 77


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

---