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)

During sporulation, Bacillus sphaericus 2362 produces a parasporal crystalline protein which is toxic for the larvae of a number of mosquito species. Using the Escherichia coli cloning vector lambda gt11, in which gene products of the inserts may be fused to beta-galactosidase, we isolated 29 bacteriophages which produced peptides-reacting with antiserum to crystal protein. On the basis of restriction enzyme analyses of the recombinants and Ouchterlony immunodiffusion experiments with induced lysogens as a source of antigens, the recombinants were assigned to three groups, designated A, B, and C. Group A consisted of three clones which appeared to express all or part of the B. sphaericus toxin gene from their own promoters and one clone producing a beta-galactosidase-toxin fusion protein. The host cells of two induced recombinant lysogens of this group were toxic to larvae of Culex pipiens. A cell suspension containing 174 ng (dry weight) of the more toxic recombinant per ml killed 50% of the larvae. Both recombinants formed peptides with molecular sizes of 27, 43, and 63 kilodaltons (kDa). The antigenically related 27- and 43-kDa peptides were distinct from the 63-kDa peptide, which resembled crystals from sporulating cells of B. sphaericus in which antigenically distinct 43- and 63-kDa proteins are derived from a 125-kDa precursor. A 3.5-kilobase HindIII fragment from recombinants having toxic activity against larvae was subcloned into pGEM-3-blue. E. coli cells harboring this fragment were toxic to mosquito larvae and produced peptides of 27, 43, and 63 kDa. The distribution of the A gene among strains of B. sphaericus of different toxicities suggested that it is the sole or principal gene encoding the larvicidal crystal protein. The two recombinants of group B and the 23 of group C were all beta-galactosidase fusion proteins, suggesting that in E. coli these genes were not readily expressed from their own promoters. The distribution of these two genes in different strains of B. sphaericus suggested that they do not have a role in the toxicity of this species to mosquito larvae.
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PMID:Cloning of the gene for the larvicidal toxin of Bacillus sphaericus 2362: evidence for a family of related sequences. 244 36

A 3.3-kilobase DNA complementary to human microtubule-associated protein 2 (MAP2) was sequenced by the dideoxy method. The 3' end terminates at an internal EcoRI site before the polyA tail. Due to the arrangement of the cDNA insert in the lambda gt11 vector, the MAP2 fragment is not fused to beta-galactosidase when expressed. The Chou Fasman algorithm for the initial 58 amino acids from the first in-frame methionine predicts an alpha helix. Beyond this point, a series of turns is predicted until amino acid 160. The frequent presence of basic residues in proximity to serines or threonines is consistent with multiple phosphorylation sites. The minimum specificity determinant for Ca2+/calmodulin-dependent kinase is repeated 13 times. The sequence of a region containing a MAP2 epitope that is shared with the Alzheimer neurofibrillary tangle was determined by DNase treatment of the cDNA and antibody selecting the small resultant clones in a lambda gt11 sublibrary. Likewise, a MAP2 epitope that is not shared with the neurofibrillary tangle also has been located. Both epitopes are in the projection portion of the molecule. A bovine MAP2 cyanogen bromide fragment, which contains the epitope shared with the neurofibrillary tangle, is partially insoluble under aqueous conditions, probably due to the aggregation of oppositely charged residues. Thus, rapid cleavage of MAP2 to small peptides is probably necessary in vivo to prevent the aggregation of larger cleavage fragments.
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PMID:Partial sequence of MAP2 in the region of a shared epitope with Alzheimer neurofibrillary tangles. 245 76

A 3.2 kb EcoRI genomic DNA fragment of Coxiella burnetii was isolated by virtue of its ability to suppress mucoidy in Escherichia coli. Nucleotide sequence analysis revealed the presence of the genes homologous to rnc, era and recO of E. coli. Suppression of capsule synthesis, measured by beta-galactosidase expression in lon- cps-lac fusion strains of E. coli, is caused by gene-dosage effects of the plasmid-borne rnc genes of either C. burnetii or E. coli. The rnc gene of C. burnetii complemented rnc- E. coli hosts for lambda plaque morphology and stimulation of lambda N gene expression. We also demonstrated heterologous complementation of an E. coli strain defective for the expression of Era, an essential protein in E. coli, using the plasmid-borne C. burnetii era. Under the control of the bacteriophage lambda PL promoter, this 3.2 kb EcoRI DNA fragment directed the synthesis in E. coli of three proteins with approximate molecular masses of 35, 27 and 25 kDa. Antibodies against purified E. coli Era protein cross-reacted with the 35 kDa protein of C. burnetii on Western blots.
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PMID:Analysis of the rnc locus of Coxiella burnetii. 783 May 73

The Drosophila melanogaster vital gene, embryonic lethal abnormal visual system (elav), is required for the postdeterminative development of the nervous system. Its gene product encodes an RNA binding protein that was found to be expressed in all neurons right after their birth. This specific, ubiquitous, and continuous pattern of neural expression has led to the increasingly popular use of ELAV protein as a neural-specific marker. To understand the molecular basis of this neural-specific expression, we have defined and analyzed the structure of the elav promoter. Cis-acting sequences important for conferring the neural specificity of elav expression were identified by analyzing the reporter gene expression in transformants carrying different elav-beta-galactosidase fusion genes. This analysis delimits a 333-bp region (-92 to +241) that is necessary for specifying the elav pattern of nervous system expression. A 3.5-kb promoter fragment encompassing this region was designed for targeting gene expression specifically to the nervous system and would be a useful tool for the analysis of nervous system function.
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PMID:Neural specificity of elav expression: defining a Drosophila promoter for directing expression to the nervous system. 820 45

A 3.6-kb EcoRI-SalI fragment of Paracoccus denitrificans DNA hybridized with a DNA probe carrying the poly(3-hydroxyalkanoate) (PHA) synthase gene (phaC) of Alcaligenes eutrophus. Nucleotide sequence analysis of this region showed the presence of a 1,872-bp open reading frame (ORF), which corresponded to a polypeptide with a molecular weight of 69,537. Upstream of the ORF, a promoter-like sequence was found. Escherichia coli carrying the fusion gene between lacZ and the ORF accumulated a level of poly(3-hydroxybutyrate) that was as much as 20 wt% of the cell dry weight in the presence of beta-ketothiolase and acetoacetylcoenzyme A reductase genes of A. eutrophus. The ORF was designated phaCPd. A plasmid vector carrying the phaCPd'-'lacZ fusion gene downstream of the promoter-like sequence expressed beta-galactosidase activity in P. denitrificans. When a multicopy and broad-host-range vector carrying the ORF along with the promoter-like sequence was introduced into P. denitrificans, the PHA content in the cells increased by twofold compared with cells carrying only a vector sequence.
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PMID:Molecular analysis of the poly(3-hydroxyalkanoate) synthase gene from a methylotrophic bacterium, Paracoccus denitrificans. 855 May 12

Incubation of human vitamin D3-binding protein (Gc protein), with a mixture of immobilized beta-galactosidase and sialidase, efficiently generated a potent macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. Stepwise incubation of Gc protein with immobilized beta-galactosidase and sialidase, and isolation of the intermediates with immobilized lectins, revealed that either sequence of hydrolysis of Gc glycoprotein by these glycosidases yields the macrophage-activating factor, implying that Gc protein carries a trisaccharide composed of N-acetylgalactosamine and dibranched galactose and sialic acid termini. A 3 hr incubation of mouse peritoneal macrophages with picomolar amounts of the enzymatically generated macrophage-activating factor (GcMAF) resulted in a greatly enhanced phagocytic activity. Administration of a minute amount (10-50 pg/mouse) of GcMAF resulted in a seven- to nine-fold enhanced phagocytic activity of macrophages. Injection of sheep red blood cells (SRBC) along with GcMAF into mice produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days.
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PMID:Structural definition of a potent macrophage activating factor derived from vitamin D3-binding protein with adjuvant activity for antibody production. 907 Jun 63

Choline acetyltransferase (ChAT) is a specific phenotypic marker of cholinergic neurons. Previous reports showed that different upstream regions of the ChAT gene are necessary for cell type-specific expression of reporter genes in cholinergic cell lines. The identity of the mouse ChAT promoter region controlling the establishment, maintenance, and plasticity of the cholinergic phenotype in vivo is not known. We characterized a promoter region of the mouse ChAT gene in transgenic mice, using beta-galactosidase (LacZ) as a reporter gene. A 3,402-bp segment from the 5'-untranslated region of the mouse ChAT gene (from -3,356 to +46, +1 being the translation initiation site) was sufficient to direct the expression of LacZ to selected neurons of the nervous system; however, it did not provide complete cholinergic specificity. A larger fragment (6,417 bp, from -6,371 to +46) of this region contains the requisite regulatory elements that restrict expression of the LacZ reporter gene only in cholinergic neurons of transgenic mice. This 6.4-kb DNA fragment encompasses 633 bp of the 5'-flanking region of the mouse vesicular acetylcholine transporter (VAChT), the entire open reading frame of the VAChT gene, contained within the first intron of the ChAT gene, and sequences upstream of the start coding sequences of the ChAT gene. This promoter will allow targeting of specific gene products to cholinergic neurons to evaluate the mechanisms of diseases characterized by dysfunction of cholinergic neurons and will be valuable in design strategies to correct those disorders.
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PMID:Identification and transgenic analysis of a murine promoter that targets cholinergic neuron expression. 988 50

A 3.2 kilobase pair DNA fragment from Thermus thermophilus HB27 coding for a beta-galactosidase activity was cloned and sequenced. A gene and a truncated open reading frame orf1 encoding respectively a beta-glycosidase (ttbeta-gly) and probably a sugar permease were located directly adjacent to each other. The deduced aminoacid sequence of the enzyme Ttbeta-gly showed strong identity with those of beta-glycosidases belonging to the glycosyl hydrolase family 1. The enzyme was overexpressed in Escherichia coli and was purified by a two-step purification procedure. The recombinant enzyme is monomeric with a molecular mass of 49-kDa. It catalyzes the hydrolysis of beta-D-galactoside, beta-D-glucoside and beta-D-fucoside derivatives. However, the kcat/Km ratio is much higher for p-nitrophenyl-beta-D-glucoside and p-nitrophenyl-beta-D-fucoside than for p-nitrophenyl-beta-D-galactoside. The specificity towards linkage positions of the disaccharides tested decreased in the following order: beta1-3 (100%) > beta1-2 (71%) > beta1-4 (40%) > beta1-6 (10%). Ttbeta-gly is a thermostable enzyme displaying an optimum temperature of 88 degrees C and a half life of 10 min at 90 degrees C. It performs transglycosylation reactions at high temperature with a yield exceeding 63% for transfucosylation reactions. On the basis of this work, the enzyme appears to be an attractive tool in the synthesis of fucosyl adducts and fucosyl sugars.
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PMID:Cloning and expression of a beta-glycosidase gene from Thermus thermophilus. Sequence and biochemical characterization of the encoded enzyme. 1058 Jun 48

The structure of the mouse Cyp2g1 gene was determined to identify regulatory regions important for its olfactory mucosa-specific expression. Two Cyp2g1 genomic clones were isolated and characterized. A 3.6-kilobase 5'-flanking sequence was used to prepare a Cyp2g1--LacZ fusion gene for transgenic mice production. Transgene expression, as determined by beta-galactosidase activity in tissue extracts, was detected in the olfactory mucosa, but not in any other tissues examined, in five different transgenic lines. Thus, the 3.6-kilobase fragment contained regulatory elements sufficient for olfactory mucosa-specific and proper developmental expression of the reporter gene. However, histological and immunohistochemical studies indicated that the expression of the transgene in the olfactory mucosa was patchy and the cellular expression patterns of the transgene did not exactly match that of the endogenous gene. These results implicate the presence of additional regulatory sequences that are necessary for the correct cell type-selectivity within the olfactory mucosa.
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PMID:Mouse cyp2g1 gene: promoter structure and tissue-specific expression of a cyp2g1-lacz fusion gene in transgenic mice. 1141 93

While somatic gene therapy has the potential to treat many genetic disorders, recent clinical trials suggest that an efficient and safe delivery vehicle for successful gene therapy is lacking. The current study examines the influence of two different preparation (the solvent evaporation method and the complex coacervation method) methods on the encapsulation of a model plasmid with chitosan. The ability of different molecular weights of chitosan to form nanoparticles with a plasmid, and particulated polymers to stabilize a plasmid in a supercoiled form, were examined by agarose gel electrophoresis. Protection of encapsulated pDNA offered by these nanoparticles from nuclease attack was confirmed by assessing degradation in the presence of DNase I, and the transformation of the plasmids with incubated nanoparticles were examined by beta-galactosidase assay. Model pDNA existed as a mixture of both supercoiled (84.2%) and open circular (15.8%) forms. Our results demonstrated that supercoiled forms decreased while open circular forms and fragmented linear forms increased during the preparation of formulations. F1 formulation prepared by the complex coacervation method protected the supercoiled form of pDNA effectively. There weren't any significant changes in nanoparticle size and zeta potential values at pH 5.5 for a period of 3 months, but differences in particle sizes were observed after lyophilization with a cryoprotective agent. The efficiency of nanoparticles mediated transformation to Escherichia coli cells was significantly higher than naked DNA or poly-L-lysine (PLL)-DNA polycation complexes. The transfection studies were performed in COS-7 cells. A 3-fold increase in gene expression was produced by nanoparticles as compared to the same amount of naked plasmid DNA (pDNA). These observations suggest that formulations with high molecular weight (HMW) chitosan can be an effective non-viral method of gene vector in animal studies.
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PMID:Chitosan-DNA nanoparticles: effect on DNA integrity, bacterial transformation and transfection efficiency. 1551 79


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