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 HO gene product of Saccharomyces cerevisiae is a site-specific endonuclease that initiates mating type interconversion. We have determined the nucleotide sequence of a 3,129-base-pair (bp) segment containing HO. The segment contains a single long open reading frame encoding a polypeptide of 586 amino acids, which has unusual (unbiased) codon usage and is preceded by 762 bp of upstream region. The predicted HO protein is basic (16% lysine and arginine) and is calculated to have a secondary structure that is 30% helical. The corresponding transcript is initiated approximately 50 nucleotides prior to the presumed initiation codon. Insertion of an Escherichia coli lacZ gene fragment into the putative HO coding segment inactivated HO and formed a hybrid HO-lacZ gene whose beta-galactosidase activity was regulated by the mating type locus in the same manner as HO (repressed by a 1-alpha 2). Upstream regions of 1,360 and 762 bp conferred strong repression; 436 bp led to partial constitutivity and 301 bp to full constitutivity. Thus, DNA sequences that confer repression of HO by a1-alpha 2 are at least 250 nucleotides upstream of the transcription start point and are within 436 nucleotides of the HO initiation codon. The progressive loss of repression suggests that both the -762 to -436 and the -436 to -301 intervals contain sites for regulation by a1-alpha 2. The HO gene contains two distinct regions that promote autonomous replication of plasmids in S. cerevisiae. These regions contain sequences that are homologous to the two conserved sequences that are associated with ARS activity.
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PMID:Structure of the Saccharomyces cerevisiae HO gene and analysis of its upstream regulatory region. 302 49

The nucleotide sequence was determined for a 3-kilobase genomic fragment containing the ornithine decarboxylase gene of Saccharomyces cerevisiae. The fragment contained two open reading frames. Gene disruption localized the ornithine decarboxylase gene to a 1398-nucleotide open reading frame. Transcription of the yeast gene initiated at several sites 171 to 211 nucleotides 5' of the translational start site. The 3' end of the transcript extended approximately 300 nucleotides beyond the end of the ornithine decarboxylase coding region and contained two copies of the yeast ARS core sequence. Translation of the ornithine decarboxylase gene appeared to initiate at the first AUG condon of the open reading frame based upon translational fusions with the Escherichia coli beta-galactosidase gene. Since no introns were apparent, the 1398-nucleotide open reading frame was predicted to encode a 466-amino acid protein with a calculated Mr = 52,369. The deduced protein differed significantly in size from previous reports on yeast ornithine decarboxylase, but was very similar in size to mammalian ornithine decarboxylase. When the predicted amino acid sequence of yeast ornithine decarboxylase was compared with that of the mouse enzyme, alignment of the sequences revealed that 40% of the amino acid residues were identical. Chou-Fasman predictions of the secondary structure of the two enzymes indicated that secondary structure was also highly conserved.
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PMID:The gene and the primary structure of ornithine decarboxylase from Saccharomyces cerevisiae. 303 69

We have used a set of deletion mutations in the ARS1 element of Saccharomyces cerevisiae to measure their effect on chromosome stability. This work establishes the previously proposed existence of three domains in ARS1. Domain C, which we have previously inferred, but not proved, to be a part of ARS1, is now established. In addition, we show that increasingly large deletions of the domain have increasingly large effects, which was not realized before. Furthermore, we have provided the first positive evidence for the central importance of a 14-base-pair core sequence containing the ARS consensus element by showing that it has the ability to act as a replicator on a plasmid containing no other ARS1 flanking sequence. The method of analyzing plasmid stability used in our study employs a novel and sensitive flow cytometry assay for beta-galactosidase. We discuss ways in which flow cytometry, based on this assay, could be generalized beyond its particular application in this work to studying other aspects of the cell biology of yeast and higher cells. The actual flow cytometry method will be described in detail elsewhere.
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PMID:Effect of ARS1 mutations on chromosome stability in Saccharomyces cerevisiae. 389 34

We have studied the effect of poly(ADP-ribose) synthetase on the interferon-gamma (IFN-gamma)-inducible expression of major histocompatibility complex (MHC) class II molecules. We constructed an expression plasmid capable of expressing either a sense RNA (MT-ARS) or an antisense RNA (pAS-FL or pAS-5') for poly(ADP-ribose) synthetase. We transfected the plasmid into mouse or human macrophage tumor cells and examined the effect on the expression of MHC class II molecules. The IFN-gamma-inducible expression of MHC class II gene was considerably reduced in transformant clones (A-2, B-2), in which the synthetase was highly expressed, whereas the depletion of the synthetase due to the expression of antisense RNA for the synthetase amplified the expression of MHC class II molecules. The results indicate that the level of the synthetase critically regulates the IFN-gamma-inducible MHC class II molecules. Next, we analyzed DNase I hypersensitive sites (DHS) of mouse MHC class II, I-A beta gene and found two sites, one in the promoter region and the other one in the first intron. The DHS in first intron was less sensitive towards DNase I attack in transformant clones (A-2, B-2) in which the synthetase was synthesized in a large quantity. Thus we constructed two beta-galactosidase reporter genes, one (A beta 2.0kb-lac z) containing the promoter region to a part of the second exon of the class II gene, and the other (A beta pro-lac z) containing the promoter region of the class II gene alone. The expression of the reporter gene was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) and found that the expression of A beta 2.0kb-lac z was suppressed in the transformant clones (A-2, B-2) relevant to control cells but the expression of A beta pro-lac z was the same level among those cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of poly(ADP-ribose) synthetase on the expression of major histocompatibility complex (MHC) class II genes. 757 32

A new, versatile baculovirus vector was developed for the generation of recombinants in the yeast Saccharomyces cerevisiae and for the expression of foreign proteins in both insect larvae and in insect cells. This vector is based on Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV) and exploits the 10-kDa protein promoter (p10) for the expression of the foreign gene. The p10 locus was used for the insertion of a yeast-selectable marker system (ARS-URA-URA3) and of a gene for screening and titration of recombinants in insect cells (beta-galactosidase). The polyhedron-positive phenotype of this vector is maintained allowing its use in insect larvae, by feeding polyhedra, and in insect cells, by infecting with budded virus. The generation of this baculovirus vector requires a single recombination step in yeast prior to infection of insect cells, but has the advantage over the vector designed previously (Patel et al., A new method for the isolation of recombinant baculovirus, Nucleic Acids Research 20 (1992) 97-104) that these vectors can also be used in insects.
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PMID:Generation of a p10-based baculovirus expression vector in yeast with infectivity for insect larvae and insect cells. 939 40

The functionality of beta-galactosidase encoded by the E. coli lacZ gene as a reporter of gene expression in C. glabrata was investigated. C. glabrata/E. coli shuttle vectors were constructed, containing both a C. glabrata CEN-ARS cassette, to allow regular segregation and episomal replication of the plasmids, and the lacZ coding sequence of E. coli. The functionality of beta-galactosidase in C. glabrata was verified by inserting the promoter and the 5' coding region of the HIS3 gene from C. glabrata directionally upstream of the lacZ gene. By fusing the promoter of the copper-controlled MTII gene to the lacZ reporter, we showed that beta-galactosidase activity can be differentially induced in C. glabrata. beta-galactosidase reporter activities were detected qualitatively by an indirect filter assay and quantitatively from permeabilized cells.
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PMID:Candida glabrata shuttle vectors suitable for translational fusions to lacZ and use of beta-galactosidase as a reporter of gene expression. 1076 36

We established a novel and convenient method to construct a ura3 strain (ura3/ura3) of the asporogenous and diploid yeast, Candida tropicalis, that produces dicarboxylic acid. One copy of the URA3 gene was disrupted using a mutated hygromycin B resistance gene (HYG#). The obtained hygromycin-resistant strain was further transformed with a URA3 disruption cassette and selected on a plate containing 5-fluoroorotic acid. The obtained strains were analyzed and the disruption of the gene was confirmed by PCR and Southern blot analysis. The results showed that the strains were obtained in which allelic URA3 genes were simultaneously disrupted. Furthermore, we established a cotransformation method for this gene disruption, using HYG# in C. tropicalis. In order to disrupt the allelic POX4 genes (encoding acyl-CoA oxidase) of dicarboxylic acid-producing strains, the ARS plasmid (which contained HYG#) and a POX4 disruption cassette (which carried the LAC4 gene encoding beta-galactosidase of Kluyveromyces lactis) were simultaneously introduced by transformation. As a result, the allelic POX4 gene was successfully disrupted.
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PMID:Novel and convenient methods for Candida tropicalis gene disruption using a mutated hygromycin B resistance gene. 1170 78