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 gene structure for S-100 beta subunit has been elucidated. The gene spans about 8 kbp and consists of 3 exons and 2 introns. The transcription initiation site was determined by an S1 nuclease mapping. The promoter region contains TATA-box-like and CAAT-box-like sequences. To examine the activity of the promoter sequence, a transfection of pS100 beta-lacZ fused gene to the cultured cells was carried out. C6 glioma cells showed a positive expression of beta-galactosidase. Gene-deletion experiments suggested the functional importance of the DNA fragment (22 bp) containing TATA-box-like and CAAT-box-like sequences. A factor protein that binds to the 100 bp DNA fragment containing the promoter sequence was specifically detected in the rat brain nuclear extract.
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PMID:Structure and expression of rat S-100 beta subunit gene. 165 88

The MET14 gene of Saccharomyces cerevisiae, encoding APS kinase (ATP:adenylylsulfate-3'-phosphotransferase, EC 2.7.1.25), has been cloned. The nucleotide sequence predicts a protein of 202 amino acids with a molecular mass of 23,060 dalton. Translational fusions of MET14 with the beta-galactosidase gene (lacZ) of Escherichia coli confirmed the results of primer extension and Northern blot analyses indicating that the ca. 0.7 kb mRNA is transcriptionally repressed by the presence of methionine in the growth medium. By primer extension the MET14 transcripts were found to start between positions -25 and -45 upstream of the initiator codon. Located upstream of the MET14 gene is a perfect match (positions -222 to -229) with the previously proposed methionine-specific upstream activating sequence (UASMet). This is the same as the consensus sequence of the Centromere DNA Element I (CDEI) that binds the Centromere Promoter Factor I (CPFI) and of two regulatory elements of the PHO5 gene to which the yeast protein PHO4 binds. The human oncogenic protein c-Myc also has the same recognition sequence. Furthermore, in the 270 bp upstream of the MET14 coding region there are several matches with a methionine-specific upstream negative (URSMet) control element. The significance of these sequences was investigated using different upstream deletion mutations of the MET14 gene which were fused to the lacZ gene of E. coli and chromosomally integrated. We find that the methionine-specific UASMet and one of the URSMet lie in regions necessary for strong activation and weak repression of MET14 transcription, respectively. We propose that both types of control are exerted on MET14.
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PMID:Cloning, nucleotide sequence, and regulation of MET14, the gene encoding the APS kinase of Saccharomyces cerevisiae. 165 9

The ROX3 gene was identified during a hunt for mutants with increased expression of the heme-regulated CYC7 gene, which encodes the minor species of cytochrome c in the yeast Saccharomyces cerevisiae. The rox3 mutants caused a 10-fold increase in CYC7 expression both in the presence and absence of heme, had slightly increased anaerobic expression of the heme-activated CYC1 gene, and caused decreases in the anaerobic expression of the heme-repressed ANB1 gene and the aerobic expression of its heme-induced homolog. The wild-type ROX3 gene was cloned, and the sequence indicated that it encodes a 220-amino-acid protein. This protein is essential; deletion of the coding sequence was lethal. The coding sequence for beta-galactosidase was fused to the 3' end of the ROX3 coding sequence, and the fusion product was found to be localized in the nucleus, strongly suggesting that the wild-type protein carries out a nuclear function. Mutations in the rox3 gene showed an interesting pattern of intragenic complementation. A deletion of the 5' coding region complemented a nonsense mutation at codon 128 but could not prevent the lethality of the null mutation. These results suggest that the amino-terminal domain is required for an essential function, while the carboxy-terminal domain can be supplied in trans to achieve the wild-type expression of CYC7. Finally, RNA blots demonstrated that the ROX3 mRNA was expressed at higher levels anaerobically but was not subject to heme repression. The nuclear localization and the lack of viability of null mutants suggest that the ROX3 protein is a general regulatory factor.
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PMID:The ROX3 gene encodes an essential nuclear protein involved in CYC7 gene expression in Saccharomyces cerevisiae. 165 37

Retinoic acid (RA) is a signalling molecule important for pattern formation during development. There are three known types of nuclear receptors for RA in mammals, RAR-alpha, RAR-beta and RAR-gamma, which transduce the RA signal by inducing or repressing the transcription of target genes. Here we describe the developmental expression pattern of the mouse RAR-beta 2 promoter. Independent lines of transgenic animals expressing RAR-beta 2 promoter sequences fused to the E. coli beta-galactosidase gene were examined throughout the course of embryogenesis and found to exhibit reproducible and specific patterns of beta-galactosidase expression in a majority of sites that have been shown previously to contain mRAR-beta transcripts. In the limbs, mRAR-beta 2 promoter activity and mRAR-beta transcripts were both excluded from precartilagenous condensations; interestingly, mRAR-beta 2 promoter activity was observed in the apical ectodermal ridge (AER) where mRAR-beta transcripts could not be detected, while no mRAR-beta 2 promoter activity or mRAR-beta transcripts were associated with the limb region that contains the zone of polarizing activity (ZPA). Analysis of the lacZ expression pattern in embryos from mothers treated with teratogenic doses of RA, indicated that mRAR-beta 2 promoter is selectively induced in a manner suggesting that overexpression of the mRAR-beta 2 isoform is involved in RA-generated malformations. The normal and induced expression pattern of the mRAR-beta 2 promoter suggests several possible roles for mRAR-beta 2 in development of the limbs, as an inhibitor of cartilage formation, in programmed cell death and in the formation of loose connective tissue.
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PMID:Developmental analysis of the retinoic acid-inducible RAR-beta 2 promoter in transgenic animals. 166 76

Screening of a Mycobacterium tuberculosis genomic DNA library in the lambda gt11 expression vector was carried out by using, as probes, sera from tuberculous patients and murine monoclonal antibody H61.3 recognizing a mycobacterial 35-kilodalton protein present only on the M. tuberculosis complex. The recombinant beta-galactosidase-fused protein present in the crude lysate induced the proliferation of T lymphocytes from patients with tuberculous pleuritis. As the recombinant insert contains an internal EcoRI restriction site, it was possible to identify two fragments, one proximal to the lacZ gene and 1.7 kilobases (kb) in size and the other distal to the lacZ gene and 2.2 kb in size. Southern blot analysis showed that both of them hybridized with the genomic DNA from M. tuberculosis and M. bovis but not with the DNA from other mycobacterial species. To perform extensive immunological studies, the amount of beta-galactosidase-fused protein being very low, we fused the 1.7-kb fragment to the N-terminal part of the gene coding for the DNA polymerase of bacteriophage MS2 in the expression vector pEx34. The fusion protein was partially purified, and subsequent Western blotting (immunoblotting) and T-cell proliferation experiments confirmed the presence of B- and T-cell mycobacterial epitopes. Furthermore, to isolate the chromosomal region containing the 35-kilodalton gene, we constructed another mycobacterial genomic library in the lambda 2001 vector by cloning 15 to 20 kb of foreign DNA. Screening of this library was carried out by using 1.7- and 2.2-kb recombinant fragments as probes. Restriction maps of some clones isolated were determined.
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PMID:Identification of a 35-kilodalton Mycobacterium tuberculosis protein containing B- and T-cell epitopes. 168 20

Overexpression of the reverse transcriptase was designed in E. coli. For a high level of expression, HIV protein was expressed as a protein fusion with beta-galactosidase. When the proviral DNA fragment covering the 3' half of the gag gene and the entire pol gene was ligated to the 3' end of the lacZ gene to fuse the truncated gag to lacZ in frame, a small quantity of reverse transcriptase was produced, indicating that frameshifting and post-translational processing have occurred. Much more reverse transcriptase was produced when the entire pol region was directly fused to the lacZ gene. From a one liter culture of bacteria, 1 mg of highly purified reverse transcriptase consisting of approximately equimolar amounts of two species (p64 and p51) was obtained. These proteins had identical N-termini consistent with the deduced amino acid sequence and therefore, might be correctly processed from the fusion protein in E. coli by the protease encoded by the pol region. The purified reverse transcriptase was enzymatically as active as the enzyme purified from the virus particles, and immunoreactive to the sera of HIV carriers with high sensitivity and specificity.
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PMID:Overproduction of human immunodeficiency virus type I reverse transcriptase in Escherichia coli and purification of the enzyme. 169 13

The Spec1 and Spec2 genes of Strongylocentrotus purpuratus are closely associated with the differentiation of aboral ectoderm. To examine cis-regulatory elements involved in the spatial expression of the Spec genes, we fused the Escherichia coli lacZ gene containing a nuclear targeting signal to 5'flanking DNA plus 5' untranslated leader sequences from Spec1, Spec2a, and Spec2c. All three genes contain 700 bp of highly conserved DNA in their upstream regions, but in Spec1 and Spec2c large insertions interrupt the conserved regions. The Spec-lacZ reporter gene plasmids were microinjected into eggs of S. purpuratus, Lytechinus variegatus, and L. pictus, and beta-galactosidase activity was determined in situ by X-gal staining. The Spec2a-lacZ fusion gene, which contained 1516 bp of 5' flanking DNA and 18 bp of 5' untranslated leader sequence, was preferentially expressed in aboral ectoderm cells in all three species. The Spec1-lacZ fusion gene was expressed in a strikingly different fashion--preferentially in primary and secondary mesenchyme cells, occasionally in aboral ectoderm cells, and less often in oral ectoderm and endoderm cells. The staining pattern was the same in either homologous or heterologous embryos. The Spec2c-lacZ fusion gene, like Spec2a-lacZ, was preferentially expressed in aboral ectoderm, but staining of other cell types was frequently observed. To further delineate sequences required for correct spatial expression, we deleted 800 bp of 5' flanking DNA from the Spec2a-lacZ fusion gene, resulting in a delta Spec2a-lacZ fusion gene that contained only the conserved DNA region. This gene fusion showed preferential expression in aboral ectoderm cells. However, the cell type specificity was not as great as with the parental Spec2a-lacZ plasmid. These experiments implied that the conserved DNA region, associated with all Spec genes examined, was insufficient for complete aboral ectoderm specificity, and suggested that a spatial repressor element existed between -1516 and -697 bp in the 5' flanking DNA of Spec2a.
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PMID:Regulatory elements from the related spec genes of Strongylocentrotus purpuratus yield different spatial patterns with a lacZ reporter gene. 170 36

In this study, we demonstrated that lipofectin-treated DNAs which were injected into mouse brain could be incorporated and expressed by brain cells. When L7RH-beta gal plasmid DNA harboring E. coli beta-galactosidase gene fused with the nuclear location signal of SV40 T-antigen gene was injected into brains of 1-week-old mice, cells whose nuclei appeared to be densely stained with the chromogenic substrate X-gal were detected in several portions of the brain till 9 days after injection. Injection of pMLV-CAT plasmid DNA which contains the E. coli chloramphenicol acetyltransferase (CAT) gene also resulted in cells immunoreactive to the anti-CAT antibody.
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PMID:Plasmid DNAs directly injected into mouse brain with lipofectin can be incorporated and expressed by brain cells. 171 37

Two short linear peptides, 17 and 14 amino acids long, on the Semliki Forest virus (SFV) E2-envelope polypeptide are shown to be involved in the protection of mice against lethal challenge with SFV. Peptides corresponding to these two regions, designated H and L, were selected for study on the basis of our model for prediction of protective epitopes on E2 polypeptide of alphaviruses. These peptides were produced in Escherichia coli as recombinant proteins fused to the amino terminus of beta-galactosidase. Both the H epitope (amino acid positions 227-243 on E2) and L epitope (amino acid positions 297-310) are recognized by antibodies raised against SFV, and both trigger antibodies that interact with native SFV-E2. Vaccination of mice with the H-beta-galactosidase polypeptide confers 64-87% protection against a lethal viral challenge (250 LD50), and immunization with L-beta-galactosidase leads to 23-66% protection of challenged mice. The efficacy of the L-based synthetic vaccine could be improved further (up to 100% protection) by presentation of this epitope as a dimer fused to beta-galactosidase. These results provide evidence that the algorithm and the methodology proposed by us previously are effective tools for identification of linear protective epitopes on E2-envelope of SFV.
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PMID:Delineation of protective epitopes on the E2-envelope glycoprotein of Semliki Forest virus. 171 35

In order to study the expression of an exogenous gene in developing mouse embryos during the preimplantation period, DNA carrying the SV40 early promoter fused with the Escherichia coli beta-galactosidase gene (lacZ) was microinjected into the pronucleus of fertilized mouse eggs. Expression of lacZ gene was detected by staining embryos with 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) as a substrate at pH 7.2. The embryos expressing the lacZ gene showed various intensities of blue staining, all showing a mosaic pattern. The exogenous gene was expressed from the 4-cell stage until the blastocyst stage. The proportion of embryos expressing the lacZ gene was maximal (38%) at the morula stage, and the expression was dependent on the presence of the SV40 promoter.
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PMID:Expression of SV40-lacZ gene in mouse preimplantation embryos after pronuclear microinjection. 172 7


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