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)

A method for detection of the primary binding of soluble tumor-associated antigens by antibodies has been developed by using an enzyme immunoassay (EIA). A heteroantiserum was produced by injecting tumor cells from a chemically induced murine sarcoma into rabbits, and antibodies reacting with most normal tissue components were removed by exhaustive in vivo absorption. A soluble preparation of tumor cells, obtained by 3 M KCl extraction, was conjugated to beta-galactosidase from Escherichia coli. The antibody binding was measured by determining the enzyme activity that could be separated by anti-antibody coprecepitation. The reaction follows saturation kinetics, and nonlabeled antigen can be readily quantitated by inhibition. The present method detects determinants common to several MC-induced tumors on the same mouse strain but absent in normal cells and nonrelated tumors in addition to individual tumor-specific transplantation antigens. The sensitivity and simplicity of the new method compare favorably with a binding assay that utilizes radioactive iodine as a label. Thus, EIA becomes a flexible tool for the further characterization and purification of these antigens.
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PMID:An in vitro immuno-enzymatic assay of tumor antigens in the mouse with beta-galactosidase. 78 74

The bone inducing factor derived from BF osteosarcoma was purified in the following manner. Step 1. The sarcoma, grown in CBA mice, was excised and lyophilized. Step 2. The powder was washed with chilled acetone. Step 3. The acetone-treated powder was then homogenized with chilled distilled water. Step 4. Washing with 0.15M KCl. Step 5. The precipitate was incubated in in 0.2 N NH2OH, pH7.0, for 48 H at 25 degrees. After Step 5, the bone-forming activity showed a slight increase; however, the factor remained insoluble. The properties of the factor were as follows. The factor is relatively relatively heat stable; the osteogenic activity survived the treatment at 75 degrees for 15 min or at 55 degrees for 19 h. The activity was easily lost by mechanical shaking. Incubation with DNase, RNase, neuraminidase, chondroitinase ABC and beta-galactosidase left the osteogenic activity intact, but treatment with either pronase or collagnease destroyed this activity. The results suggest that the factor may be a protein. The activity was seen with the lyophilized BF osteosarcoma cells (without matrix), and it is probable that the factor was exclusively synthesized in the cells. The bone formation, observed across a millipore filter when living BF osteosarcoma enclosed in a millipore chamber was implanted in mice, suggests the synthesis and secretion of the factor from the cells.
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PMID:Studies on a factor responsible for new bone formation from osteosarcoma in mice. 105 58

We report here that differentiated, primary, postmitotic neurons and photoreceptors in cultures obtained from embryonic chicks can express foreign genes after transfection by the calcium phosphate method. A variety of viral promoters were tested by using either beta-galactosidase or chloramphenicol acetyltransferase as reporter genes. Histochemical and immunocytochemical analysis showed beta-galactosidase expression by both neurons and photoreceptors. As commonly observed with dividing cells, transfection efficiencies showed inter-experimental variability, with efficiencies ranging from 2% to 20% using the same plasmid. On the other hand, intra-experimental variability between replicate dishes was much smaller. Analysis using the highly sensitive enzymatic assay for chloramphenicol acetyl transferase (CAT) showed that all of the promoter/enhancers-CAT constructs tested, with the exception of a construct containing the Maloney sarcoma virus promoter, led to the expression of detectable activity when transfected into cultured retinal cells. The calcium phosphate treatment used for cell transfection did not show detectable effects on overall cell survival, although it caused selective decreases in some metabolic activities of the cells. The studies demonstrate that it is possible to obtain expression of genes transfected into primary, postmitotic neuronal cells.
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PMID:Expression of transfected genes by differentiated, postmitotic neurons and photoreceptors in primary cell cultures. 231 22

It has been shown by us that the human blood-group MN antigenic determinants are not the products of allelomorphic genes as believed so far, but that N is the precursor substance of M and that the allelomorph to the M gene is amorph. The determinant structure of the N antigen is branched and possesses as non-reducing termini beta-d-galactopyranosyl (Gal) and alpha-N-acetylneuraminic acid (NANA) linked to beta-Gal. The M substance differs from N only in that alpha-NANA covers the terminal beta-Gal of the N determinant. Vicia graminea anti-N reacts with terminal beta-Gal of the N antigen as well as its precursor. A human blood-group N-like antigen in the cell surface of the TA3 mammary adenocarcinoma (ascites form) has been found by us. The TA3 cancer occurs as the non-strain specific Ha subline and as the strain-specific St subline. This is the first description of an N-like antigen in a non-primate as well as a tumor. This antigen reacts with Vicia anti-N. In serological specificity the Vicia agglutinin is closely related to the Thomsen-Friedenreich anti-T agglutinin present in most human and animal sera. These sera plus complement kill ordinary TA3-St cells and sialidase-treated Ha cells to less than 95 percent. Untreated TA3-Ha cells are fully resistant even though they absorb cytotoxin. Beta-galactosidase treatment of either Ha or St cells abolishes the killing activity of the sera. The cancer cells absorb anti-T but they lose this capability after exposure to beta-galactosidase. An immunological cross-relationship between the human blood-group MN antigens and the receptor for an oncogenic virus, the avian subgroup B leukosis sarcoma virus has been observed.
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PMID:Relation of human blood-groups MN to cancer cell surface antigens and to receptors for oncogenic viruses. 414 44

A fetal antigen (FA) was isolated from spent culture medium of a melanoma (M14) cell line. Allogeneic serum samples from melanoma patients, previously characterized with respect to anti-FA activity, were used as the source of anti-FA antibody. The FA activity was partially purified by membrane ultrafiltration, gel filtration, and chloroform:methanol extraction. The partially purified FA was then used to develop an enzyme-linked immunosorbent assay (ELISA). By indirect ELISA both the IgG and IgM classes of anti-FA antibodies were detected in the sera of cancer patients and normal volunteers. The incidences of anti-FA antibodies in the sera of cancer patients and normal volunteers were not significantly different. As detected by competitive inhibition in ELISA, FA activity was widely distributed among melanoma, sarcoma, and carcinoma tumor tissues and cultured tumor cells, as well as among fetal brain, skin, and muscle tissues. FA activity was destroyed by treatment with beta-galactosidase and hyaluronidase, but it was not destroyed by proteolytic and lipolytic enzymes. The antigen bound to immobilized ricin, peanut, and soybean lectins. FA activity in material purified by ricin-affinity chromatography was associated with molecules in the 60,000- to 70,000-dalton region as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These results suggest a glycoprotein nature for the FA isolated from the spent culture medium of melanoma (M14) cells; this FA apparently elicits formation of natural antibodies in the cancer patients and normal donors.
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PMID:Immunochemical characterization of fetal antigen isolated from spent medium of a human melanoma cell line. 619 35

Bacterial expression of the transforming region of Moloney murine sarcoma virus, designated mos, was obtained as a fusion protein with a portion of the small tumor antigen of polyoma virus. This was accomplished by fusing the entire mos open reading frame, encoding a 41,000-dalton protein, with a plasmid that expresses a beta-galactosidase-polyoma fusion protein under lac operon control. The resulting plasmid directed synthesis of the predicted polyoma antigen-sarcoma virus fusion protein of 59,000 daltons. This protein was immunoprecipitated by an anti-polyoma tumor antigen antiserum that recognized polyoma determinants at the NH2 terminus of the hybrid protein. This protein was also immunoprecipitated by an antiserum directed against a synthetic peptide containing the 12 COOH-terminal amino acids encoded by the mos open reading frame. This work confirms the existence of a long open reading frame in the mos gene and resolves a discrepancy between different nucleotide sequences for its COOH-terminal coding region.
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PMID:Expression of transforming region of Moloney murine sarcoma virus in Escherichia coli as a fusion protein with small tumor antigen of polyoma virus. 627 95

We developed a rapid assay for identifying growth-arrest genes to facilitate studies of cell cycle regulation. A7r5 vascular smooth muscle cells were transiently transfected with two plasmids: (i) a pMSV beta Gal reporter construct expressing beta-galactosidase (beta-gal) under transcriptional control of the murine sarcoma virus long terminal repeat; and (ii) a eukaryotic expression vector driving transcription of a potential growth inhibitory c-DNA under control of the cytomegalovirus promoter/enhancer. Twenty-four hours after transfection, cellular DNA was labeled for an additional 24 h with 5-bromo-2-deoxyuridine (BrdU) to label cellular DNA. After fixation, transfected cells were identified by histochemical staining with a beta-gal substrate, 6-chloro-3-indolyl-beta-D-galactopyranoside (i.e., Red-Gal). Transfected cells (beta-gal-positive) that traversed S phase (i.e., DNA synthesis) were quantified by indirect immunocytochemical staining for BrdU. Since autoradiography was not required to score for DNA synthesis, the length of experiments was much shorter than previously described growth-arrest assays performed with transiently transfected cells. Experiments with two growth-arrest genes, p53 and the p21 cyclin-dependent kinase inhibitor, demonstrated the utility of this assay.
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PMID:Rapid characterization of growth-arrest genes in transient transfection assays. 754 21

The introduction of genetic sequences into hematopoietic stem cells (HSC) has allowed study of HSC proliferation in vivo by proviral-sequence molecular analysis in the DNA of progeny. Analysis of HSC proliferation could be enhanced by development of a retroviral vector that encodes a reporter gene that allows sensitive detection of transduced cells. We developed a recombinant retrovirus vector encoding the reporter gene lacZ under the transcriptional control of the myeloproliferative sarcoma virus long-terminal repeat (LTR). Bone marrow cells from C3H mice were co-cultured on retrovirus producer cell lines and cultured for growth of colony-forming unit granulocyte/macrophage (CFU-GM) and high proliferative potential colony-forming cells (HPP-CFC) in semisolid media or were transplanted into irradiated recipients. In other experiments, recombinant retrovirus was injected in vivo into the liver of developing fetal rat pups, and circulating hematopoietic cells of the postnatal rats were analyzed for evidence of proviral integration and expression of beta-galactosidase. Expression of lacZ was detected in both CFU-GM and HPP-CFC that were cultured immediately following in vitro infection of mouse bone marrow. Beta-galactosidase activity from the retrovirus was also detected in both marrow cells isolated from reconstituted mice 22 weeks following transplantation as well as in blood cells of postnatal rats transduced in utero with the recombinant retrovirus. This strategy may be especially useful for characterizing proliferation of transduced populations of hematopoietic cells and in the development of protocols for somatic gene therapy.
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PMID:Myeloproliferative sarcoma virus directed expression of beta-galactosidase following retroviral transduction of murine hematopoietic cells. 760 Dec 55

Several series of microinjection of the RSV-lacZ gene (the Escherichia coli beta-galactosidase gene under the control of the long terminal repeat of the Raus sarcoma virus) into fertilized mud loach eggs were carried out. The expression of the transgene in 3-5 day-old fry was shown to depend neither upon the stage of fry development at which the RSV-lacZ gene was introduced (early blastodisc, late blastodisc, 2-blastomere embryo) nor upon the region of transgene injection (blastodisc cytoplasm or egg yolk). Additionally, when injected into yolk, a smaller number of transgene expression points were observed and their distribution was confined to the surface of the yolk sac. In some experimental series, transgene expression was observed in 100% of embryos. The presence of exogenous genetic material in one of the experimental series was proved for 100% of 5- to 6-week old juveniles, when injected into cytoplasm, and for 67% of juveniles, when injected into yolk. This work provides evidence of the possibility of 100% transfer and expression of exogenous DNA when transgenic loachs are generated by injection into embryos and fry at different stages of their development.
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PMID:[Analysis of expression of the RSV-lacZ-gene in transgenic embryos of the loach Misgurnus fossilis L. during different variations of injection]. 763 15

To express high levels of proteins encoded by transfected DNA constructs in a variety of cultured cells, including neuronal cells, the activities of nine different promoters were evaluated using Escherichia coli beta-galactosidase (beta-gal) (LacZ) as a reporter gene. These nine promoters were categorized into three distinct groups (high, intermediate, and low expresser), in terms of the levels of beta-gal expression. An expression vector containing the cytomegalovirus enhancer and the chick beta-actin promoter (high expresser) showed the highest levels of expression, followed by vectors containing the cytomegalovirus promoter/enhancer and the SV40 promoter/enhancer (intermediate expresser). The rest of the promoters (thymidine kinase, adenovirus, murine proliferative sarcoma virus, nerve growth factor receptor, Rous sarcoma and mouse mammary tumor virus, and beta-amyloid precursor protein) expressed low levels of beta-gal. These results were consistent for eight different cell types. A particularly attractive model is the stem cell, P19; cultures differentiating into progeny consisting predominantly of cholinergic neurons could be readily transfected with expression vectors using liposomes and expressed beta-gal without significant morphologic changes of the differentiated neurons. The systems should be useful for the study of promoters and various expressed proteins, including those involved in axonal transport.
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PMID:Activity assays of nine heterogeneous promoters in neural and other cultured cells. 806 55


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