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)

The ability of two different enzyme-antibody conjugates to detect specific antibodies has been compared. beta-Galactosidase was conjugated to antibodies raised against rabbit Fc fragments using m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS). Horseradish peroxidase (HRP) was conjugated to part of the same batch of antibodies using the periodate method. The beta-galactosidase and HRP labels enabled detection of approximately 8 fmoles and 4 fmoles respectively of human growth hormone (HGH) antibodies, when their enzyme activities were measured spectrophotometrically. The detection limit of the beta-galactosidase label was increased 4-fold when a fluorimetric detection system was employed.
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PMID:A comparison of the ability of beta-galactosidase and horseradish peroxidase enzyme-antibody conjugates to detect specific antibodies. 11 16

Oncogenic activation of ras results in changes in the transcription of several genes leading to uncontrolled cell growth. In this paper, we demonstrate that transformation of fibroblast cells by the ras oncogene leads to transcriptional repression of the smooth muscle alpha-actin promoter. Transient transfection analysis of plasmids containing the 5' upstream region of the human alpha-actin gene fused to human growth hormone or bacterial chloramphenicol acetyltransferase coding sequences into Rat-2 and ras-transformed Rat-2 (HO6) cells indicates that alpha-actin promoter is repressed in ras-transformed cells. In addition, stable rat fibroblast cell lines expressing human growth hormone or beta-galactosidase under the control of alpha-actin promoter exhibit repressed reporter gene activity following transformation by the ras oncogene. alpha-Actin promoter-driven beta-galactosidase activity is derepressed in revertants of ras-transformed stable cell lines. This revertant cell line expresses elevated levels of ras p21 protein and is resistant to retransformation by Ki and Ha-ras oncogenes. The revertant may have either a defective target protein whose activity is essential for the transforming activity of ras or an activated tumor suppressor gene which can suppress the activity of ras. These results indicate that smooth muscle alpha-actin promoter activity is a sensitive marker to follow phenotypic changes following transformation by ras and subsequent reversion. The advantages of this alpha-actin promoter-reporter gene assay system to screen for drugs that inhibit the transforming activity of ras, either directly or indirectly, are discussed.
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PMID:Regulation of smooth muscle alpha-actin promoter in ras-transformed cells: usefulness for setting up reporter gene-based assay system for drug screening. 145 76

A recombinant vaccinia virus was employed to demonstrate infection of cultured Xenopus laevis melanophores. The recombinant virus contains one copy each of the Escherichia coli lac Z and human growth hormone genes under the transcriptional control of two separate viral promoters. Western blot analysis and in situ staining revealed the dependency of beta-galactosidase production in infected Xenopus cells on time and multiplicity of infection (MOI). Western blot analysis was used to demonstrate the production of a 65 kD vaccinia late protein and its variation over time and with MOI. When virus preparations from infected Xenopus cells were attempted, no amplification of virus was observed and only a minute portion of the original innoculum was recovered. We therefore propose an abortive infection of Xenopus pigment cells by vaccinia virus: The amphibian cells allow for the synthesis of viral proteins, but not for the efficient replication of competent virus. The findings have implications not only for our understanding of the virus/host interaction, but also for the efficient expression of exogenously introduced genes in cultured Xenopus melanophores.
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PMID:A recombinant vaccinia virus infects Xenopus melanophores. 181 50

The ability to stably deliver recombinant proteins to the systemic circulation would facilitate the treatment of a variety of acquired and inherited diseases. To explore the feasibility of the use of genetically engineered myoblasts as a recombinant protein delivery system, stable transfectants of the murine C2C12 myoblast cell line were produced that synthesize and secrete high levels of human growth hormone (hGH) in vitro. Mice injected with hGH-transfected myoblasts had significant levels of hGH in both muscle and serum that were stable for at least 3 weeks after injection. Histological examination of muscles injected with beta-galactosidase-expressing C2C12 myoblasts demonstrated that many of the injected cells had fused to form multinucleated myotubes. Thus, genetically engineered myoblasts can be used for the stable delivery of recombinant proteins into the circulation.
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PMID:Systemic delivery of recombinant proteins by genetically modified myoblasts. 196 3

A recombinant gene encoding human growth hormone (hGH) was stably introduced into cultured myoblasts with a retroviral vector. After injection of genetically engineered myoblasts into mouse muscle, hGH could be detected in serum for 3 months. The fate of injected myoblasts was assessed by coinfecting the cells with two retroviral vectors, one encoding hGH and the other encoding beta-galactosidase from Escherichia coli. These results provide evidence that myoblasts, which can fuse into preexisting multinucleated myofibers that are vascularized and innervated, may be advantageous as vehicles for systemic delivery of recombinant proteins.
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PMID:Systemic delivery of human growth hormone by injection of genetically engineered myoblasts. 196 3

The BMLF1 region of the Epstein-Barr virus (EBV) genome and the immediate-early (IE) region of human cytomegalovirus (HCMV) both encode proteins which can trans-activate heterologous promoter/chloramphenicol acetyl transferase (CAT) constructs, including a human immunodeficiency virus type-1 promoter/CAT construct. We demonstrate here that this trans-activation by the EBV BMLF1 gene product, which we have previously shown to be largely post-transcriptional, is reporter gene dependent. In contrast, trans-activation by the HCMV-IE gene product(s), previously shown to be mediated at the RNA level, is seen regardless of whether CAT, human growth hormone, or beta-galactosidase is used as the reporter gene. Mutational analysis revealed no specific cis-acting sequences within the HIV-1 promoter which were required for trans-activation by the HCMV-IE gene product(s).
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PMID:Disparate effects of two herpesvirus [corrected] immediate-early gene trans-activators on the HIV-1 LTR. 255 54

The spatially restricted expression of mammalian homeobox genes in teh embryonic central nervous system (CNS) provides an opportunity to study the basis of spatial gene regulation in mammalian development. Here, we define a regulatory region of the murine Hox 1.3 gene that mediates such a region-specific expression pattern. The Hox 1.3 gene contains two exons, encodes a putative protein of 270 amino acids, and is expressed preferentially in the spinal cord at midgestation. We have analyzed transgenic mice containing various Hox 1.3 DNA fragments fused to reporter sequences, such as a human growth hormone gene fragment or the E. coli lacZ structural gene. As shown by RNAase protection assays or by in situ analyses of beta-galactosidase activity, several hybrid genes are expressed in the embryonic central nervous system in a spatially restricted manner, along both the rostrocaudal and dorsoventral axes. A 912 nucleotide sequence located immediately upstream of the Hox 1.3 coding sequence is sufficient to direct expression to the dorsolateral cells of the brachial spinal cord.
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PMID:Spatial regulation of homeobox gene fusions in the embryonic central nervous system of transgenic mice. 290 48

For use in monitoring transcription in operon fusion, we have constructed a lacZ sequence with the initiation codon ATG and the Escherichia coli consensus Shine-Dalgarno site. There are unique restriction endonuclease sites flanking the sequence to allow easy isolation of the lacZ sequence with or without the Shine-Dalgarno site. We have placed this lacZ sequence behind the bovine growth hormone (BGH) gene and found that the lacZ product beta-galactosidase synthesized reflects the level of BGH-specific mRNA.
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PMID:Use of lacZ expression to monitor transcription. 314 48

We have isolated several recombinant clones carrying the complementary DNA (cDNA) sequence of the rainbow trout (rt) Salmo gairdneri growth hormone (GH) mRNA by immunoblot screening using an antiserum to chum salmon (Oncorhyncus keta) GH. The nucleotide sequence of one of the rtGH cDNA clones (pAF51) was determined. The rt cDNA sequence in pAF51 encodes a hybrid polypeptide of 199 amino acid residues containing 9 amino acid residues of the bacterial beta-galactosidase, one residue from the codon at the junction of the beta-galactosidase gene, and the rtGH cDNA sequence, an additional residue from the presumptive signal peptide of the pre-rtGH and the entire sequence of the mature rtGH (188 amino acid residues). Pairwise matrix comparisons of the hydropathy profiles of bovine, human, rat, and rainbow trout GH polypeptides indicate that regions of similarity exist between the rtGH and mammalian GH. In particular, there are two major regions of similarity found near the amino-terminal region and at the carboxy-terminal region. These regions correspond to hydrophilic domains of the GH molecules. The possible significance of these domains is discussed.
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PMID:Rainbow trout growth hormone: molecular cloning of cDNA and expression in Escherichia coli. 354 20

We studied reporter gene expression in synovial tissue after intra-articular administration of an expression plasmid into the knees of rabbits and rats. In both species, administration of a plasmid encoding beta-galactosidase led to gene expression in the synovial cells lining the joint. Expression correlated with the presence of plasmid DNA in synovial tissue extracts. Studies with a plasmid encoding chloramphenicol acetyltransferase demonstrated that gene expression persists for 2-5 days after administration. Southern blotting demonstrated that the administered plasmid was taken up rapidly by synovial tissue and degraded. By 24 hr after administration, no intact plasmid could be detected by Southern blotting, although small amounts of plasmid could be amplified by PCR up to 7 days. Administration of a plasmid encoding human growth hormone demonstrated that this product could be expressed from synovial cells and secreted into the synovial fluid. The histological distribution of gene expression in synovium resembles the known distribution of particulate materials injected into the joint and suggests that plasmid DNA is taken up by nonspecific endocytosis like other particulate materials during the remodeling of synovial fluid.
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PMID:Gene transfer to synovial cells by intra-articular administration of plasmid DNA. 757 97


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