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

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

Hybrid proteins composed of beta-galactosidase and polypeptides of the bovine leukaemia virus (BLV) including those of the main core protein p24, the envelope protein gp51 and the transmembrane protein gp30 were produced in Escherichia coli and immunologically characterized. The hybrid proteins were immunologically reactive with sera from cattle naturally infected with BLV, demonstrating a possible use for diagnosis of BLV infection. Detection of antibodies was most sensitive with the p24 derivative.
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PMID:Immunological characterization of BLV proteins synthesized in Escherichia coli. 170 91

The ADP/ATP translocator, a transmembrane protein of the mitochondrial inner membrane, is coded in Saccharomyces cerevisiae by the nuclear gene PET9. DNA sequence analysis of the PET9 gene showed that it encoded a protein of 309 amino acids which exhibited a high degree of homology with mitochondrial translocator proteins from other sources. This mitochondrial precursor, in contrast to many others, does not contain a transient presequence which has been shown to direct the posttranslational localization of proteins in the organelle. Gene fusions between the PET9 gene and the gene encoding beta-galactosidase (lacZ) were constructed to define the location of sequences necessary for the mitochondrial delivery of the ADP/ATP translocator protein in vivo. These studies reveal that the information to target the hybrid molecule to the mitochondria is present within the first 115 residues of the protein. In addition, these studies suggest that the "import information" of the amino-terminal region of the ADP/ATP translocator precursor is twofold. In addition to providing targeting function of the precursor to the organelle, these amino-terminal sequences act to prevent membrane-anchoring sequences located between residues 78 and 98 from stopping import at the outer mitochondrial membrane. These results are discussed in light of the function of distinct protein elements at the amino terminus of mitochondrially destined precursors in both organelle delivery and correct membrane localization.
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PMID:Sequences required for delivery and localization of the ADP/ATP translocator to the mitochondrial inner membrane. 302 60

Serologic testing for human immunodeficiency virus type 1 (HIV-1) is currently based on enzyme linked immunosorbent assay (ELISA) as screening method. Positive ELISA-results have to be confirmed by at least one second procedure such as Western blotting or immunofluorescence. To obtain new diagnostic reagents for confirmatory testing, we expressed viral antigens in procaryotic systems. Peptides representing epitopes of structural core (gag)- and envelope (env)-proteins of HIV were produced in E. coli as stable immunogenic beta-galactosidase fusion proteins. Recombinant proteins were taken for immunoblot-assays. The results of Western blotting with those fusion proteins were in general comparable with conventional ELISA, immunofluorescence, immunoblot with cell-culture derived virus and commercially available ELISA tests based on recombinant proteins. Immunoblots using recombinant transmembrane protein (gp41) derived polypeptide were more sensitive than the conventional procedure with purified virion proteins. Western blotting with recombinant fusionproteins provide reliable and inexpensive serodiagnostics without handling of infectious cell cultures.
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PMID:[Serologic AIDS diagnosis with polypeptides obtained by genetic technics of the human immunodeficiency virus (HIV-1)]. 332 45

Ectopic expression of neutral proteins, such as beta-galactosidase, in developing embryos has been an invaluable tool for studies of gene expression and embryonic development. However, expression of beta-galactosidase does not reveal the shape of the cells containing it. We have examined the suitability of rat CD2, a small transmembrane protein of the immunoglobulin superfamily, as a marker of cell morphology in Drosophila. We selected the regulatory sequences of the Drosophila mesoderm-specific gene twist to express CD2 and prepared a chimeric gene, twi-CD2. Embryos containing twi-CD2 faithfully express CD2 in the same pattern as Twist. Expression of CD2 on the surface of cells reveals the shape of cells when stained with existing monoclonal antibodies. We have also constructed a CD2 gene that can be used with the GAL4 system and show that CD2 can be expressed on the surface of epithelial cells and along the length of axons.
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PMID:Mammalian CD2 is an effective heterologous marker of the cell surface in Drosophila. 772 1

In order to have a proper biosynthesis and secretion of the melanin-pigment granules (melanosomes) the melanocyte may require a melanosome-associated molecule that provides a signal for assembly and organization of melanogenic enzymes and proteins within the compartment of melanosomes. This study reports the presence of a Ca(2+)-binding phosphoprotein, p90, which can be engaged in such melanogenic function, located on the melanosomal membrane of human melanocytes. A human melanoma cDNA expression library in lambda Zap II was screened with a rabbit polyclonal antibody raised against human melanosomes isolated from cultured human melanoma cells, SK MEL 23. A cDNA encoding a melanosomal protein, M(r) 90 kDa, was identified through this immunoscreening. A partial sequencing of nucleotides (822 bp from the N-terminal domain) of this clone (3.8 kb) and predicted amino acids showed more than 90% homology with dog calnexin, a previously reported endoplasmic reticulum (ER) transmembrane protein. A fusion protein of this p90 with beta-galactosidase expressed in Escherichia coli revealed both the immuno-cross-reactivity with anti-dog calnexin and anti-human melanosome antibodies and the Ca(2+)-binding property. Upon immunohistochemistry, the anti-dog calnexin antibody revealed the positive immunoreactivities with both normal and malignant human melanocytes, showing a much higher expression of antigenic epitope than nonmelanocytic human cells. The laser scanning confocal immunofluorescence, using an antibody against a human melanosome-specific antigen (HMSA-5), and immunoelectron microscopy, using immunogold, confirmed the major localization of anti-dog calnexin antibody epitope on the melanosomes and ER.
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PMID:Identification of a cDNA coding for a Ca(2+)-binding phosphoprotein (p90), calnexin, on melanosomes in normal and malignant human melanocytes. 826 46

To generate T cell-specific retroviral vectors an scFv phage display library derived from immunized mice was selected for binding to the human T cell line Molt-4/8. The scFv cDNAs recovered from the selected phages were transiently expressed as an N-terminal fusion of the spleen necrosis virus (SNV) transmembrane protein (TM) subunit of the viral envelope protein (Env) in the cell line DSH-cxl, which packages the beta-galactosidase gene into SNV particles. Screening of supernatants from about 150 transfections resulted in the identification of 5 scFvs that mediated efficient transduction of Molt-4/8 cells. Using stable packaging cell lines vector preparations with titers greater than 10(4) EFU/ml on human T cells were obtained. The scFv 7A5 in particular was able to mediate selective transduction of human T cells with high efficiency. Titers of up to 106 EFU/ml were reached on Molt-4/8, Jurkat, and A301 cells, while titers on HeLa cells, TE671 cells, 293T cells, and HT1080 cells were below 102 EFU/ml. Transduction of stimulated primary human peripheral blood cells, which consisted mainly of T cells, was about fivefold more efficient than transduction of B cells. Western blot analysis of supernatant from the 7A5 packaging cells demonstrated incorporation of 7A5-TM into vector particles and indicated proteolytic processing of the coexpressed unmodified TM during particle formation. Binding of bacterially expressed 7A5-scFv to a panel of cell lines correlated well with the transduction results. These data provide the first proof of concept that a general approach can be taken to obtain scFvs able to mediate selective gene transfer into target cells.
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PMID:Targeting human T cells by retroviral vectors displaying antibody domains selected from a phage display library. 1068 Aug 43

Gene trapping in mouse embryonic stem cells is an efficient method for identifying new genes and examining their functions. This method has been used in an effort to identify some novel genes involved in mouse development. In the present paper, one such gene named IZP6 is reported. Expression of the IZP6 gene, as monitored by beta-galactosidase expression in heterozygous mice, was detected in a developmentally regulated fashion: the expression pattern has two phases during the embryogenesis. In the first phase, from embryonic day 11.5 (E11.5) until E14.5, the reporter gene is mainly expressed in the forebrain. In the second phase, from E15.5 until birth, expression in the forebrain becomes weaker but is still observed in the olfactory bulb and the skin around the eyes, nose, limbs and tail. Thus, IZP6 gene expression changes from the central nervous system (the first phase) to the peripheral tissues (the second phase) during development. The IZP6 gene encodes a protein of 228 amino acids. Analysis of the secondary structure of the IZP6 protein revealed four hydrophobic regions, indicating that the IZP6 protein is a four transmembrane region protein. These results suggest that IZP6 is a transmembrane protein related to neurogenesis in the mouse.
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PMID:A novel putative transmembrane protein, IZP6, is expressed in neural cells during embryogenesis. 1142 94

The control of cellular physiology and gene expression in response to extracellular signals is a basic property of living systems. We have constructed a synthetic bacterial signal transduction pathway in which gene expression is controlled by extracellular Zn2+. In this system a computationally designed Zn2+-binding periplasmic receptor senses the extracellular solute and triggers a two-component signal transduction pathway via a chimeric transmembrane protein, resulting in transcriptional up-regulation of a beta-galactosidase reporter gene. The Zn2+-binding site in the designed receptor is based on a four-coordinate, tetrahedral primary coordination sphere consisting of histidines and glutamates. In addition, mutations were introduced in a secondary coordination sphere to satisfy the residual hydrogen-bonding potential of the histidines coordinated to the metal. The importance of the secondary shell interactions is demonstrated by their effect on metal affinity and selectivity, as well as protein stability. Three designed protein sequences, comprising two distinct metal-binding positions, were all shown to bind Zn2+ and to function in the cell-based assay, indicating the generality of the design methodology. These experiments demonstrate that biological systems can be manipulated with computationally designed proteins that have drastically altered ligand-binding specificities, thereby extending the repertoire of genetic control by extracellular signals.
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PMID:Computational design of a Zn2+ receptor that controls bacterial gene expression. 1450 Sep 2

The glomerular filtration barrier separates the blood from the urinary space. Nephrin is a transmembrane protein that belongs to the immunoglobulin superfamily and is localized to the slit diaphragms that are a critical component of this filtration barrier. Mutations in the nephrin gene (NPHS1) lead to congenital Finnish nephropathy, whereas alterations in the level of nephrin expression have been identified in a wide range of acquired glomerular diseases. A 186-bp fragment from the human NPHS1 promoter is capable of directing podocyte-specific expression of a beta-galactosidase transgene when placed in front of a heterologous minimal promoter in transgenic mice. The Wilms tumor suppressor gene (WT1) is a zinc-finger-containing transcription factor that is coexpressed with NPHS1 in differentiated podocytes; gel shift binding assays demonstrate that a recombinant WT1 protein can bind and activate the 186-bp NPHS1 fragment in a sequence-specific manner. Taken together, these results suggest that WT1 may be required for regulation of the NPHS1 gene in vivo.
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PMID:WT1 activates a glomerular-specific enhancer identified from the human nephrin gene. 1550 38

The cytoplasmic domain of human immunodeficiency virus type 1 (HIV-1) envelope (Env) transmembrane protein gp41 interacts with the viral matrix MA protein, which facilitates incorporation of the trimeric Env complex into the virus. It is thus feasible to design an anti-HIV strategy targeting this interaction. We herein describe that Gag expression can be downregulated by a cytoplasmic domain fusion protein of the Env transmembrane protein, beta-galactosidase (beta-gal)/706-856, which contains the cytoplasmic tail of gp41 fused at the C terminus of Escherichia coli beta-gal. This mediator depleted intracellular Gag molecules in a dose-dependent manner. Sucrose gradient ultracentrifugation and confocal microscopy revealed that Gag and beta-gal/706-856 had stable interactions and formed aggregated complexes in perinuclear, intracellular sites. Pulse-chase and cycloheximide chase analyses demonstrated that this mediator enhanced unmyristylated Gag degradation. The results demonstrate a novel mode of HIV-1 Gag downregulation by directing Gag to an intracellular site via the interaction of Gag with a gp41 cytoplasmic domain fusion protein.
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PMID:Downregulation of human immunodeficiency virus type 1 Gag expression by a gp41 cytoplasmic domain fusion protein. 1647 34


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