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 DNA fragments of the 5' and 3' halves of the putative env gene predicted from the DNA sequence of human T-cell leukemia virus (HTLV) provirus were inserted into expression vectors pORF2 and pORF1, respectively, and two hybrid proteins composed of env polypeptides and beta-galactosidase were efficiently produced in Escherichia coli. The hybrid proteins containing the NH2-terminal (EH9) and COOH-terminal (EA1) halves were both immunologically reactive with sera from adult T-cell leukemia patients, demonstrating the utility of the hybrid proteins for diagnosis of HTLV infection. Rabbit antisera against these hybrid proteins detected the two glycoproteins gp62 and gp46, which were previously identified as HTLV env gene products. With these rabbit antisera, two properties of the env gene products were studied. (i) The antisera inhibited syncytia formation of cat S+L- cells induced by HTLV, suggesting that one or both of the env gene products of HTLV, gp62 and gp46, are involved in induction of cell fusion. (ii) The env product gp62 or gp46 or both products are exposed on the surface of HTLV-infected cells and might modulate the proliferation of HTLV-infected T cells in the host because the antisera against the hybrid proteins were cytotoxic on HTLV-producing cell lines. The latter conclusion also is supported by the fact that adult T-cell leukemia patients and healthy HTLV carriers have antibodies to the env gene products.
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PMID:Envelope proteins of human T-cell leukemia virus: expression in Escherichia coli and its application to studies of env gene functions. 609 Nov 39

A method is presented whereby antigenic determinants recognized by specific monoclonal antibodies can be mapped to specific sites on a protein sequence with high resolution. Short DNase I-generated DNA fragments encoding portions of the protein of interest are molecularly cloned into the EcoRI site of the beta-galactosidase gene of phage lambda Charon 16 so as to obtain expression of random protein fragments as fusion proteins. The monoclonal antibody is used to screen the phage library to isolate phage expressing the specific antigenic determinant. DNA of immunoreactive phage can be analyzed rapidly and subcloned to allow DNA sequence determination. The method is generally applicable and permits antigenic determinants of functionally interesting monoclonal antibodies to be mapped and related to specific protein sequences. We have used this procedure to determine the region of the feline leukemia virus envelope protein gp70 recognized by a virus-neutralizing monoclonal antibody, cl.25. Antibody binding was mapped to a 14-amino acid region in the amino-terminal half of gp70. This region may be directly involved in an essential function of the gp70 protein, perhaps in gp70-mediated host recognition functions. Synthetic peptides derived from this region may provide useful vaccine antigens for the prevention of feline leukemia virus-associated disease in cats.
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PMID:Method to map antigenic determinants recognized by monoclonal antibodies: localization of a determinant of virus neutralization on the feline leukemia virus envelope protein gp70. 620 25

The biochemical activities of 8 lysosomal acid hydrolases in leukemic cells from 48 patients were examined. Characteristic alterations were found in alpha-mannosidase, beta-galactosidase and N-acetyl-beta-glucosaminidase activities of leukemic cells. The level of alpha-mannosidase activity was much higher in myelo(mono)genous leukemias (AML, AMoL, AMMoL, CML and CMMoL) than in lymphogenous ones (ALL, T-cell leukemia, hairy cell leukemia and CLL) without exception. The beta-galactosidase activity also differed as a result of alpha-mannosidase, except in T-cell leukemia. In T-cell leukemia it was within the range of normal lymphocytes, but in the other lymphogenous leukemias it was significantly below normal. N-acetyl-beta-glucosaminidase activity in myelo(mono)genous leukemic cells was above the range of normal granulocytes. The changes in these enzyme levels were consistent. The lymphocytic or myelocytic nature of three cases of acute undifferentiated leukemia could be determined by enzyme studies. In two cases it was lymphocytic and in one it was myelocytic. The enzymatic abnormalities were also found in morphologically mature neutrophils from patients but not only chronic types (CML, CMMoL) but also acute types (AMoL, AMMoL) of leukemias, and were similar to those of their respective leukemic cells. Analysis of lysosomal enzymes (at least three of those mentioned above), can elucidate one of the biochemical properties of leukemic cells and may be valuable in the differentiation of leukemias.
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PMID:Biochemical activities of lysosomal acid hydrolases in leukemic cells. 694 81

We report the possibility to transfer marker genes coding for beta-galactosidase activity using retroviral vectors into human peripheral blood CD34+ cells, peripheral blood T-lymphocytes and into the growth factor-dependent human hematopoietic cell line TF-1. Using the MFG-nisLacZ and the FLac vector and various packaging cell lines, we demonstrated retroviral transfer and high expression of a bacterial beta-galactosidase activity induced by the nisLacZ gene or the Sh-ble/LacZ gene. Kinetics of expression of the transgenes were analyzed both in primary cells and cell lines. Absence of cytotoxicity related to the expression of the bacterial beta-galactosidase was assessed in both cell types. These results open interesting prospectives for the use of the beta-galactosidase activity to mark and follow the fate of genetically modified cells isolated from patients prior to reimplantation.
Leukemia 1995 Oct
PMID:Hematological reconstitution and gene therapy: retroviral transfer of the bacterial beta-galactosidase activity into human hematopoietic CD34+ cell populations and into T lymphocytes derived from the peripheral blood. 747 15

Recent developments in gene therapy techniques enable us to introduce new genetic information into hematopoietic cells. Among the various techniques, we focused on two viral vector systems, one using a retrovirus and the other an adenovirus. By using an adenoviral vector we could transduce and highly express bacterial beta-galactosidase (LacZ) gene under the control of the CAG (cytomegalovirus enhancer with chicken beta-actin promoter) promoter in various hematopoietic cells, although the expression persisted for only two weeks. The retroviral vector (MFG) could transduce the LacZ gene into hematopoietic cells almost as well as the adenoviral vector using the repetitive infection protocol. The retroviral system could maintain the expression of transduced cells quite longer than the adenoviral system. Differential use of these two vector systems may be helpful for the gene transduction into various kinds of hematopoietic cells (Lin et al., manuscript in preparation).
Leukemia 1995 Oct
PMID:Transduction of LacZ gene into leukemia cells using viral vectors of retrovirus and adenovirus. 747 16

A problem in utilizing herpes simplex virus (HSV) as a vector for expression of foreign genes in CNS neurons has been the inability to facilitate long-term expression of the engineered genes. Previously, we showed that the murine moloney leukemia virus LTR would drive beta-galactosidase (beta-gal) transcription for extended periods from the latent viral genome in sensory, but not motor neurons. In this communication we further evaluate the utility of the LTR promoter for use in long-term expression vectors. Following stereotactic injection of 8117/43 (an ICP4 minus, non-replicating virus with the LTR driving the beta-gal gene, or KD6 (an ICP4 minus non-replicating virus not expressing beta-gal) into the hippocampus of rats, polymerase chain reaction (PCR) analysis of viral DNA after 2 months indicated that latent infections were established. Assaying by both x-gal staining and reverse transcriptase PCR we demonstrate that (1) beta-gal can be detected for at least 6 months in hippocampal neurons, and (2) although the number of beta-gal transcripts in these cells drops considerably by 2 weeks, they can be detected during the period studied. These studies indicate that the LTR promoter is active and affords long-term expression in the CNS, albeit at comparatively low levels compared to those observed at acute times.
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PMID:Long-term expression of a reporter gene from latent herpes simplex virus in the rat hippocampus. 747 33

Genetically modified myogenic cells have a number of potentially relevant applications for gene therapy of genetic defects. Retroviral vectors proved to be a safe and efficient tool to transfer and express genes into satellite cells and their differentiated progeny, although muscle-specific regulation of the transferred gene is very difficult to achieve in a conventional vector framework. We modified a Moloney murine leukemia virus (MoMLV)-derived retroviral vector containing a bacterial beta-galactosidase (beta-Gal) reporter gene by inserting a muscle creatinine kinase (MCK) enhancer element into the U3 region of the viral long terminal repeat (LTR). The resulting vector (mLBSN) was transferred into cells of different histological origin, including undifferentiated murine and human myogenic cells, which were unable to express the transgene at detectable levels. Instead, gene expression from the modified LTR was obtained in a mouse myogenic cell line and in human primary satellite cells upon induction of differentiation into myotubes in culture, and correlated with the activation of the muscle differentiation program. beta-Gal-negative, mLBSN-transduced human satellite cells were also transplanted into the quadricep muscle of immunodeficient mice, where activation of the transgene expression was observed in vivo after differentiation and fusion into muscle fibers. These results show that retroviral vectors carrying LTRs modified in the enhancer sequences may be used to target tissue- and differentiation-specific gene expression into the muscle. For practical purposes, satellite cells engineered by muscle-specific retroviral vectors might represent an effective tool to deliver expression of a given gene product specifically into the muscle tissue, avoiding undesired protein accumulation in mononucleated cells. More generally, this type of vector might be useful whenever regulated expression of a transferred gene is necessary in a target cell or tissue.
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PMID:A retroviral vector containing a muscle-specific enhancer drives gene expression only in differentiated muscle fibers. 754 73

The HOX11 homeobox gene was identified via the translocation t(10;14) in T cell leukaemia. To determine the function of this gene in mice, null mutations were made using homologous recombination in ES cells to incorporate lacZ into the hox11 transcription unit. Production of beta-galactosidase from the recombinant hox11 allele in +/- mutants allowed identification of sites of hox11 expression which included the developing spleen. Newborn hox11 -/- mice exhibit asplenia. Spleen formation commences normally at E11.5 in hox11 -/- mutant embryos but the spleen anlage undergoes rapid and complete resorption between E12.5 and E13.5. Dying spleen cells exhibit molecular features of apoptosis, suggesting that programmed cell death is initiated at this stage of organ development in the absence of hox11 protein. Thus hox11 is not required to initiate spleen development but is essential for the survival of splenic precursors during organogenesis. This function for hox11 suggests that enhanced cell survival may result from the t(10;14) which activates HOX11 in T cell leukaemias, further strengthening the association between oncogene-induced cell survival and tumorigenesis.
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PMID:The Hox11 gene is essential for cell survival during spleen development. 755 17

We have developed a model system in the rat to test the feasibility of recombinant protein expression by genetically modified peritoneal mesothelial cells following autologous peritoneal implantation. Rat primary peritoneal mesothelial cells, isolated from parietal peritoneum by enzymatic digestion, were stably transduced (using a Moloney murine leukemia virus (MoMLV)-derived retroviral vector, BAG, expressing the Escherichia coli lacZ gene) to mark the cells with a reporter protein (beta-galactosidase, beta-gal). Such transduced mesothelial cells, tagged with DiO, a fluorescent lipophilic dye used for long-term tracing of transplanted cells, were then reseeded on the denuded peritoneal surface of syngeneic recipients. DiO-labeled, BAG-transduced mesothelial cells were observed to repopulate the denuded areas and remain attached there for > 90 days. Moreover, these genetically modified mesothelial cells continued to express the reporter gene product in vivo (ie beta-gal activity was present for at least 1 month). Our results demonstrate the feasibility of ex vivo gene therapy using peritoneal mesothelial cells.
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PMID:Mesothelial cell-mediated gene therapy: feasibility of an ex vivo strategy. 758 14

Rat natural killer cell Met-ase-1 (RNK-Met-1) is a 30,000 M(r) serine protease (granzyme) found in the cytolytic granules of CD3- large granular lymphocytes (LGL) with natural killer (NK) activity. To characterize the genomic sequences responsible for the CD3- LGL-restricted expression of this gene, we screened a rat genomic library with RNK-Met-1 cDNA, and obtained bacteriophage clones that contained the RNK-Met-1 gene. The RNK-Met-1 gene comprises 5 exons and spans approximately 5.2 kilobases (kb), exhibiting a similar structural organization to a class of CTL-serine proteases with protease catalytic residues encoded near the borders of exons 2, 3, and 5. The 5'-flanking region of the RNK-Met-1 gene contains a number of putative promoter and enhancer regulatory elements and shares several regions of homology with the 5'-flanking region of the mouse perforin gene. We have prepared nested deletions from approximately 3.3 kb of the 5'-flanking region of the RNK-Met-1 gene, and inserted these upstream of the chloramphenicol acetyltransferase (CAT) reporter gene. These 5'-flanking RNK-Met-1-CAT constructs were transiently transfected into rat LGL leukemia, T-lymphoma, and basophilic leukemia cell lines. The transcriptional activity of the RNK-Met-1 5'-flanking region was strong, restricted to the RNK-16 LGL leukemia and controlled by several positive cis-acting regions spread over at least 3.3 kb. The longest and most active 5'-flanking region (-3341 to -33) was also used to drive specific expression of beta-galactosidase in RNK-16. These data are consistent with the NK cell-specific expression of RNK-Met-1 and suggest the potential utility of this gene promoter in the development of transgene models of NK cell biology in vivo.
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PMID:Cloning and characterization of a novel NK cell-specific serine protease gene and its functional 5'-flanking sequences. 760 1


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