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)

In conjugation with donor strains carrying proximal F merogenotes of KLF-1 type about 100-fold lower frequency of Leu+ or Lac+ recombinants was found. The determination of the level of beta-galactosidase synthesis during the initial period of mating indicated that the transfer process of plasmid DNA was not impaired. Among the recombinants selected a large fraction have not expressed the plasmic fertility functions. This phenomenon was found to be replicon specific and was observed only with proximal F merogenotes but not with classical F'lac and F'ORF-1 elements or R1-19 plasmid. The expression of KLF-1 plasmid functions in the cell seems to be affected by a chromosomal gene of the proximal F merogenote closely linked to leu marker.
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PMID:The maintenance affinities of KLF-1 proximal F merogenotes in Escherichia coli. 77 95

Varicella-zoster virus (VZV) ORF 47 lies in the unique long region of the VZV genome. Sequence homology studies have demonstrated that gene 47 possessed conserved protein kinase motifs. In this study, we investigated the properties of the ORF 47 product. First, a rabbit antiserum was raised against a protein generated from the fusion of the most antigenic ORF 47 domain with Escherichia coli beta-galactosidase. The high-titer antiserum reacted specifically with ORF 47 polypeptides translated in vitro. When incubated with VZV-infected cell lysate, the antiserum immunoprecipitated a phosphoprotein of M(r) 54,000, a size comparable with the predicted molecular mass. The precipitated viral protein was phosphorylated in a protein kinase assay; subsequent phosphoamino acid analysis indicated that the phosphotransferase associated with the ORF 47 protein was a serine protein kinase. Synthesis of the ORF 47 product in VZV-infected cell culture increased in the first and second days and plateaued after the third day of infection. The protein kinase activity associated with VZV ORF 47 had several distinctive biochemical properties: (i) its phosphotransferase activity was enhanced more by manganese than by magnesium, (ii) it utilized both ATP and GTP as donors of phosphate, and (iii) it phosphorylated both acidic and basic substrates. In summary, this report lends support to the computer homology data which predicted that VZV ORF 47 would encode a serine protein kinase.
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PMID:Serine protein kinase associated with varicella-zoster virus ORF 47. 132 39

In order to investigate whether or not the UL56 gene is involved in those processes determining the viral pathogenicity and latency, a recombinant virus HSV-1-M-LacZ was constructed in which the DNA sequences between nucleotide position (np) 116030 and 121753 were replaced by the E. coli beta-galactosidase (LacZ) gene. This deletion spans from the carboxyterminus of UL55 (np 116030) to the second exon of IE110 (np 121753) eliminating UL56 and the variable region of the BamHI DNA fragment B which were implicated in intraperitoneal pathogenicity and latency. The host range and growth kinetics of the recombinant virus HSV-1 M-LacZ were comparable to the parental strain HSV-1 F. As expected it was found that HSV-1-M-LacZ lost its virulent phenotype and was not able to develop acute infection in animals. The state of the UL56 gene was investigated by determining the cDNA sequence of the UL56 gene transcript of HSV-1 F using PCR products obtained after amplification of the cDNA with oligonucleotide primers corresponding to the translational start and stop codons of this gene. This analysis revealed that the DNA sequence of the UL56 gene of HSV-1 F differed from those DNA sequences determined for the genomic DNA of HSV-1 strain 17. Between nucleotide position 116343 and 116344 two nucleotides -AG- are inserted which prolong the ORF of the UL56 gene to 233 amino acids with a predicted molecular weight of 30 kDa.
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PMID:Elimination of UL56 gene by insertion of LacZ cassette between nucleotide position 116030 to 121753 of the herpes simplex virus type 1 genome abrogates intraperitoneal pathogenicity in tree shrews and mice. 166 44

Tc1 is a transposon present in several copies in the genome of all natural isolates of the nematode C.elegans; it is actively transposing in many strains. In those strains Tc1 insertion is the main cause of spontaneous mutations. The transposon contains one large ORF that we call TcA; we assume that the TcA protein is the transposase of Tc1. We expressed TcA in E.coli, purified the protein and showed that it has a strong affinity for DNA (both single stranded and double stranded). A fusion protein of beta-galactosidase and TcA also exhibits DNA binding; deletion derivatives of this fusion protein were tested for DNA binding. A deletion of 39 amino acids at the N-terminal region of TcA abolishes the DNA binding, whereas a deletion of 108 C-terminal amino acids does not affect DNA binding. This shows that the DNA binding domain of TcA is near the N-terminal region. The DNA binding capacity of TcA supports the assumption that TcA is a transposase of Tc1.
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PMID:TcA, the putative transposase of the C. elegans Tc1 transposon, has an N-terminal DNA binding domain. 215 34

Mouse hepatitis virus (MHV) gene 5 contains two open reading frames. We have expressed the second open reading frame of this gene (gene 5 ORF 2) in an Escherichia coli expression system. This system utilized a plasmid which contained the promoter and the first 36 codons of the recA gene fused in frame with the MHV gene 5 ORF 2, which is fused in turn to the beta-galactosidase gene. The protein product of this gene fusion was used to raise antibody to gene 5 ORF 2. The specificity of the antibody was verified by immunoprecipitation of the in vitro transcribed and translated protein product of gene 5 ORF 2. The second reading frame of MHV gene 5 was shown to be expressed during the course of infection by immunocytochemistry and radioimmunoprecipitation using the antibody raised against the E. coli fusion protein and by two-dimensional gel electrophoresis.
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PMID:Detection of a murine coronavirus nonstructural protein encoded in a downstream open reading frame. 283 66

Sequence analysis of the hepatitis B virus (HBV) genome revealed the presence of an open reading frame (ORF X) which has the potential to encode a 154-amino acid polypeptide. A fusion protein containing 145 of the amino acids encoded by ORF X and 8 amino acids of beta-galactosidase was expressed and characterized in bacterial extracts. Immunoprecipitations with the ORF X fusion protein as a radioactively labeled antigen were performed to screen sera of humans infected with HBV for the presence of antibodies against ORF X-encoded determinants (anti-X). Such antibodies were identified in 9 samples from a set of 26 sera characterized as positive for HBV surface antigen but were not found in 16 normal human sera. The data reported here demonstrate that sera from some patients with markers of HBV infection contain antibodies directed against the polypeptide encoded by ORF X. As such, these findings represent evidence that ORF X constitutes a gene, or a portion of a gene, which is expressed during HBV infection. Although there does not appear to be a direct relationship between anti-X and any individual markers of HBV infection, our data suggest that anti-X is more prevalent in HBV-positive sera containing antibodies to HBe3 antigen (anti-HBe3).
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PMID:Hepatitis B virus polypeptide X: expression in Escherichia coli and identification of specific antibodies in sera from hepatitis B virus-infected humans. 351 Mar 11

A recombinant plasmid, pCB300, was constructed which carries a cauliflower mosaic virus (CaMV) DNA insert corresponding to nucleotides 1825-2280, including the coding sequence (1830-2219) of open reading frame III (ORF III). This CaMV DNA insert was fused with the amino-terminal portion of the beta-galactosidase gene. Transcription of the hybrid gene is controlled by the lac promoter, which is repressed in Escherichia coli strain JM103 and can be induced by isopropylthio-beta-D-galactoside (IPTG). When the promoter is derepressed, cells harboring the chimeric plasmid produce an Mr 16 000 fusion protein. This protein is immunodetected by antibodies raised against an amino terminal synthetic peptide of 19 amino acids corresponding to a sequence predicted from the nucleotide sequence of ORF III.
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PMID:Expression of a putative plant viral gene in Escherichia coli. 609 36

The chloroplast trnK gene for tRNALys(UUU) from mustard contains a 2574 bp group II intron with a long open reading frame for 524 amino acids. The encoded polypeptide appears to be structurally related to mitochondrial maturases which are involved in splicing. To study the properties of the intron encoded protein, we overexpressed the trnK ORF as a beta-galactosidase fusion protein in E. coli and carried out RNA-protein binding experiments with crude bacterial extracts and the purified fusion protein. Both gel-shift and UV-crosslinking experiments revealed preferential binding to the trnK precursor transcript. Of two other RNA probes containing chloroplast group II introns, the trnG precursor was recognized by the trnK ORF protein, but the rps16 precursor was not. Competition binding experiments indicate that G-residues seem to play a role in RNA-protein interaction. RNA-binding activity of the trnK intron encoded polypeptide is consistent with its suggested function as a plastid maturase, hence justifying the assignment matK for this gene.
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PMID:RNA-binding activity of the matK protein encoded by the chloroplast trnK intron from mustard (Sinapis alba L.). 753 69

In Bacillus subtilis, the AhrC protein represses genes encoding enzymes of arginine biosynthesis and activates those mediating its catabolism. To determine how this repressor also functions as an activator, we attempted to clone catabolic genes by searching for insertions of the Tn917-lacZ transposon that express AhrC-dependent, arginine-inducible beta-galactosidase activity. One such isolate was obtained. The region upstream of lacZ was subcloned in Escherichia coli in such a way that it could be replaced in the B. subtilis chromosome after appropriate manipulation. Analysis of exonuclease III-derived deletions located an AhrC-dependent, arginine-inducible promoter to within a ca. 1.9 kb fragment. The sequence revealed: the 3' end of an ORF homologous to gdh genes encoding glutamate dehydrogenase, with highest homology to the homologue from Clostridium difficile; the 5' end of an ORF homologous to a Saccharomyces cerevisiae gene encoding delta 1-pyrroline 5-carboxylate dehydrogenase (P5CDH), an enzyme of arginine catabolism; and just upstream of the latter, a sequence with homology to known AhrC binding sites in the upstream part of the biosynthetic argCJBD-cpa-F cluster. The same region has also been sequenced by others as part of the B. subtilis genome sequencing project, revealing that the P5CDH gene is the first in a cluster termed rocABC. Restriction fragments containing the putative AhrC-binding sequence, but not those lacking it, showed retarded electrophoretic mobility in the presence of purified AhrC. A 277 bp AhrC-binding fragment also showed anomalous mobility in the absence of AhrC, consistent with its being intrinsically bent. DNAse I footprinting localized AhrC binding to bp -16/-22 to +1 (the transcription startpoint). Such a location for an activator binding site, i.e. overlapping the transcription start, is unusual.
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PMID:A binding site for activation by the Bacillus subtilis AhrC protein, a repressor/activator of arginine metabolism. 756 95

Serial passage of nuclear polyhedrosis viruses (NPVs) through cultured cell lines results in the appearance of mutants with a complex phenotype referred to as the 'few polyhedra' (FP) phenotype. The altered plaque morphology and reduced occlusion production associated with the FP phenotype have been observed in Autographa californica multinucleocapsid nuclear polyhedrosis virus (AcMNPV) bearing mutations in the gene encoding the 25 kDa protein (25K gene). In this study, we sequenced the 25K genes of four spontaneously occurring AcMNPV FP mutants. These mutants, together with an artificially generated FP mutant (AcFP beta gal, in which the gene for beta-galactosidase is fused in frame with the 25K ORF), were examined at the ultrastructural level to see if they exhibited the reduced virion occlusion and intranuclear envelopment which is associated with the FP phenotype. Observations on Spodoptera frugiperda Sf9 cells infected with the FP mutants revealed that all five mutants were impaired in virion occlusion and intranuclear nucleocapsid envelopment. The 25K mutants were also found to release two- to fivefold more infectious virus (p.f.u.) into the media of infected Sf9 cells. Marker rescue of AcFP beta gal restored wild-type virion occlusion, intranuclear envelopment and levels of infectious virus production.
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PMID:Mutations in the Autographa californica multinucleocapsid nuclear polyhedrosis virus 25 kDa protein gene result in reduced virion occlusion, altered intranuclear envelopment and enhanced virus production. 778 73


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