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 series of expression plasmids was constructed to compare the usefulness of various promoters for the synthesis of a given protein in the Saccharomyces cerevisiae. The plasmids pMBL212, -213, -214, -215 and -216 can be used to synthesize the protein of interest directly as a non-fused protein or, if the protein is difficult to detect, indirectly as an enzymatically active beta-galactosidase fusion protein. The plasmids were employed to identify which yeast promoter and strain are suitable for the synthesis of poliovirus protein VP2. It was concluded that the GAL7 and PGK promoters in combination with strain X904 can be used for efficient synthesis of a VP2 in the form of a N-terminally fused VP2-beta-galactosidase protein.
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PMID:Construction of expression plasmids for Saccharomyces cerevisiae: application for synthesis of poliovirus protein VP2. 312 75

The ability of the bacteriophage 434 operator/repressor system to function in a eukaryotic cell has been explored. An idealized 434 operator was placed at various positions in the PGK promoter of Saccharomyces cerevisiae: within the upstream activator sequence, close to the TATA box, and downstream of the transcription-initiation site. Expression of the 434 cI gene from a 2 microns-based plasmid resulted in significant repression of gene expression from constructs containing the altered promoters linked to a beta-galactosidase reporter gene. Attempts to use a variant of the 434 repressor that has the binding specificity of the P22 repressor (434P22) were unsuccessful, due to a severely inhibitory effect of this gene-product on the growth of the yeast cells.
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PMID:The bacteriophage 434 operator/repressor system in yeast. 749 31

Possible functions of the c-mos proto-oncogene during spermatogenesis were investigated through perturbations of its expression in transgenic mice. Two promoters, one from the pre-meiotic male germ cell-specific mouse phosphoglycerate kinase 2 gene, and the other from the post-meiotic male germ cell-specific rat RT7 gene were used to direct expression of c-mos. Northern blot analysis of testis RNA from transgenic PGK-c-mos mice indicated elevated levels of c-mos RNA in spermatocytes and spermatids compared to controls. No transgene expression was detected in any other tissue examined, suggesting that the mouse PGK2 promoter, like the previously used human PGK2 promoter, confers correct cell-specific expression onto c-mos. The promoter from a newly characterized rat gene, RT7, was shown to direct expression specific to post-meiotic spermatids. Transgenic mice carrying an RT7-lacZ construct displayed immunoreactive bacterial beta-galactosidase as well as enzyme activity in round spermatids. The cellular specificity for beta-galactosidase expression observed in RT7-lacZ transgenic animals was in agreement with endogenous RT7 transcript expression. Northern blot analysis of testis RNA of RT7-c-mos transgenic mice showed elevated levels of c-mos in spermatids, but not in other cells or tissues examined. Western blot analysis demonstrated elevated levels of p43c-mos in spermatids of both PGK-c-mos and RT7-c-mos transgenic animals, but only PGK-c-mos transgenics had increased p43c-mos levels in spermatocytes. Both RT7-c-mos and PGK-c-mos transgenic mice are fertile and show no tendency toward transformation. RT7-c-mos mice have no discernible phenotype associated with the c-mos overexpression in spermatids. However, PGK-c-mos transgenic males exhibited a significant increase in germ cell number, as determined by cell counts using total germ cells and germ cells fractionated by centrifugal elutriation. Because mitotic divisions of germ cells occur prior to PGK-c-mos transgene expression, our observations suggest that c-mos overexpression in spermatocytes causes an alteration in cell-cell interactions.
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PMID:Cell interactions in testis development: overexpression of c-mos in spermatocytes leads to increased germ cell proliferation. 773 67

In order to realize a novel vaccination treatment for malignant gliomas using tumor cells genetically modified to express certain cytokines, it is essential to achieve an efficient gene transduction into primary cultured cells. We investigated the feasibility of preparing a glioma vaccine through retrovirus-mediated gene transduction. Glioma cells were cultured primarily from surgically resected tumor tissues of six patients. We obtained more than 1000-fold proliferation of cultures within eight weeks in all six cases. In vitro infection with a recombinant retrovirus GKlacZ carrying an Escherichia coli beta-galactosidase marker gene resulted in over 65% gene transfer to the primary cultured glioma cells. Further enrichment (approximately 90%) of transduced cells was possible by employing repeated infections or using vectors with neo' marker gene. Two cytokine genes, granulocyte-macrophage colony-stimulating factor and interleukin-4, were introduced into glioma cells by sequential transduction with two single-expression GK vectors. The transduced glioma cells produced high levels of both cytokines. We also evaluated simultaneous introduction of two genes with double-expression GK vectors containing internal ribosomal entry site (IRES) or internal promoter (PGK). Although the cells transduced with double-expression vectors secreted both cytokines, the level of the gene product following IRES or PGK was 10 times lower than that of the upstream gene product. The transduced cells retained cytokine secretion in vitro for 14 days after 100 Gy irradiation. Our data indicate the feasibility of retrovirus-mediated preparation of gene-modified tumor vaccines from clinical glioma materials, which could be useful for potentiating antitumor immunity in glioma patients.
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PMID:Efficient retrovirus-mediated cytokine-gene transduction of primary-cultured human glioma cells for tumor vaccination therapy. 914 Jan 15

Cystic fibrosis (CF) is a common autosomal recesses disease in which loss of CFTR-Cl- channel function of defective cAMP-stimulated Cl- transport transfer across airway epithelia. Recombinant adenoviruses have shown progress as vectors with which to transfer CFTR cDNA to CF airway epithelia. Here we investigated variables involved in adenovirus-mediated transfer of CFTR by measuring cAMP- stimulated Cl- transport in CF airway epithelia grown as monolayers on permeable filter supports. When we compared the effects of different promoters, we found that persistent correction of Cl- transport was obtained when the vector contained the E1a promoter, or to a lesser extent the PGK promoter. Vector containing the CMV promoter produced a greater initial cAMP-stimulated Cl- current, but the duration of correction was shorter and the infection procedure itself increased CFTR expression, suggesting that high input doses of virus stimulate expression. We compared the level of expression, measured with a beta-galactosidase reporter of CFTR mRNA, with CFTR-mediated Cl- transport. Even low levels of expression generated significant Cl- current and marked increases in expression produced only modest increments in Cl- current. Correction of the CF Cl- transport defect was also improved when the concentration of adenovirus vector was high and when the duration of contact with the epithelium was prolonged. These findings may help optimize the ability of adenovirus vectors encoding CFTR to correct the CF Cl- transport defect.
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PMID:Adenovirus-mediated generation of cAMP-stimulated Cl- transport in cystic fibrosis airway epithelia in vitro: effect of promoter and administration method. 915 6

A new Cre-reporter strain of mouse has been developed that expresses a fusion protein derived from the lacZ gene fused to GFP with a nuclear localization signal. This construct is expressed from the ROSA26 locus upon Cre-mediated recombination that removes a loxP-flanked PGK-neo cassette, thus allowing for detection of Cre activity in all tissues. This reporter strain, which is similar to prior R26R and R26EGFP strains, has certain advantages related to the nuclear expression and the combined expression of both beta-galactosidase and GFP activities. We show that the use of this newly developed reporter line allows for enhanced resolution, detection and co-localization. Thus, we report a previously unrecognized subset of venous endothelial cells derived from Pax3 expressing precursors.
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PMID:Cre reporter mouse expressing a nuclear localized fusion of GFP and beta-galactosidase reveals new derivatives of Pax3-expressing precursors. 1839 35