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 COX6 gene encodes subunit VI of cytochrome c oxidase. Previously, this gene and its mRNAs were characterized, and its expression has been shown to be subject to glucose repression/derepression. In this study we have examined the effects of heme and the HAP1 (CYP1) and HAP2 genes on the expression of COX6. By quantitating COX6 RNA levels and assaying beta-galactosidase activity in yeast cells carrying COX6-lacZ fusion genes, we have found that COX6 is regulated positively by heme and HAP2, but is unaffected by HAP1. Through 5' deletion analysis we have also found that the effects of heme and HAP2 on COX6 are mediated by sequences between 135 and 590 base pairs upstream of its initiation codon. These findings identify COX6 as the fourth respiratory protein gene that is known to be regulated positively by heme and HAP2. The other three, CYC1, COX4, and COX5a, encode iso-1-cytochrome c, cytochrome c oxidase subunit IV, and an isolog, Va, of cytochrome c oxidase subunit V, respectively. Thus, it appears that the biogenesis of two interacting proteins, cytochrome c and cytochrome c oxidase, in the mitochondrial respiratory chain, are under the control of common factors.
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PMID:Transcription of yeast COX6, the gene for cytochrome c oxidase subunit VI, is dependent on heme and on the HAP2 gene. 254 Jan 69

Expression of the allantoin system genes in Saccharomyces cerevisiae is induced by allophanate or its analog, oxalurate. This work provides evidence for the involvement of distinct types of cis-acting elements in the induction process. The first element was found to have the properties of an upstream activation sequence (UAS). This element was localized to a 16-base-pair (bp) DNA fragment containing a short 5-bp sequence that occurred repeatedly in the upstream region of DAL7. When present in two or more copies, the 16-bp fragment supported high-level beta-galactosidase production in a CYC1-lacZ expression vector; there was, however, no response to the allantoin pathway inducer. The second element had the properties of a negatively acting element or upstream repression sequence (URS). This element was localized to a 16-bp DNA fragment containing an 8-bp sequence that was repeated four times in the upstream region of DAL7. A fragment containing the 8-bp repeated sequence placed adjacent to the UAS-containing fragment mediated inhibition of the ability of the UAS to support lacZ expression regardless of whether inducer was present. A third element, designated an upstream induction sequence (UIS), was required for response to inducer. The UIS was localized to a small DNA fragment containing an approximately 10-bp sequence that was repeated twice in the upstream region of DAL7. When a fragment containing the 10-bp repeated sequence was placed adjacent to these UAS and URS elements, the construction (UIS-UAS-URS) supported normal oxalurate-mediated induction of beta-galactosidase synthesis. These data are consistent with the suggestion that multiple, cis-acting elements participate in the induction process.
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PMID:The DAL7 promoter consists of multiple elements that cooperatively mediate regulation of the gene's expression. 255 87

The cDNAs encoding full-length chicken oviduct progesterone receptor B (PRB) and a truncated receptor (C1C2) lacking the amino-terminal domain were expressed in yeast (Saccharomyces cerevisiae) using a ubiquitin fusion system. The expression of the fusion protein is under the control of a copper-responsive yeast metallothionein promoter, and the fusion protein is subsequently cleaved by the yeast host enzyme to produce receptor protein. Western immunoblot analyses of yeast extracts containing full-length PRB revealed a polypeptide co-migrating with authentic chicken oviduct PRB. Using a polyclonal antibody (907) directed against the "hinge" region of the authentic chicken progesterone receptor, a 42-kDa polypeptide was detected by Western analysis in yeast extracts containing C1C2 receptors. Standard hormone binding assays indicated that these receptors produced in yeast cells exhibited steroid binding affinity and specificity characteristic of the authentic chicken progesterone receptor. To test for progesterone receptor-mediated activation of transcription in yeast, reporter plasmids were constructed to transform yeast cells expressing PRB or C1C2 receptors. The reporter gene contained two copies of a progesterone response element upstream of the yeast proximal CYC1 promoter fused to the beta-galactosidase gene of Escherichia coli. The induction of beta-galactosidase activity by PRB and C1C2 was strictly dependent on specific ligand and the presence of a progesterone response element. However, overproduced C1C2 receptors had an adverse effect on the transcription of the lacZ gene. It was found that when overproduced C1C2 was activated by progesterone, an inhibitory effect on normal yeast cell growth was evident. These observations suggest that C1C2 is a potent trans-acting factor in yeast and that the amino-terminal domain of the chicken progesterone receptor may play a role in selective modulation of target gene activation.
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PMID:Expression of functional chicken oviduct progesterone receptors in yeast (Saccharomyces cerevisiae). 268 42

Transcriptional activation by the yeast CYC1 upstream activation site UAS2UP1 requires the products of both the HAP2 and HAP3 regulatory genes. We show here that both HAP2 and HAP3 in yeast extracts bind to UAS2UP1 and give rise to a single protein-DNA complex, termed C, in nondenaturing polyacrylamide gels. That both products are a part of complex C was shown by altering the mobility of the complex by fusing either HAP2 or HAP3 to beta-galactosidase. Further, methylation interference footprinting showed that sequences in UAS2UP1 contacted in complex C were identical to those contacted in either fusion protein complex. Binding was centered on the sequence TGATTGGT, also found in the UASs of other genes subject to activation by the HAP2-HAP3 system and homologous to the CCAAT box sequence found in higher cells. The binding of either HAP2 or HAP3 was abolished when synthesized in a strain mutant in the complementary HAP gene. Thus the binding of HAP2 and HAP3 to UAS2UP1 is interdependent. The involvement of multiple gene products in binding to a single site is discussed with reference to other systems in yeast and higher cells.
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PMID:Yeast HAP2 and HAP3 activators both bind to the CYC1 upstream activation site, UAS2, in an interdependent manner. 282 15

A regulatory element has been identified in the promoter region of the gene encoding the 11 kDa subunit VIII of the ubiquinol-cytochrome c oxidoreductase in Saccharomyces cerevisiae. The element, which is approximately 40 bp long and situated 185 bp upstream of the initiator ATG, is essential for induction of gene expression during growth in the presence of non-fermentable carbon sources. This is shown by the regulated synthesis of beta-galactosidase in yeast cells harbouring a CYC1-lacZ fusion gene, in which the CYC1 UAS's had been replaced by a 43 bp subunit VIII gene promoter fragment. In addition two DNA-binding activities, which may represent either separate factors or different forms of a single factor, have been detected. Both factors are abundant and they bind in a mutually exclusive fashion to a DNA sequence just upstream of the regulatory element. Although it is unlikely that these factors are directly involved in the response of the subunit VIII gene to catabolite repression, the position of their binding sites relative to the UAS and to the 3'-terminus of a gene located only 361 bp upstream suggest that they are important in modulating transcriptional activity of this region.
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PMID:Demarcation of a sequence involved in mediating catabolite repression of the gene for the 11 kDa subunit VIII of ubiquinol-cytochrome c oxidoreductase in Saccharomyces cerevisiae. 284 Jun 33

To initiate a genetic analysis of yeast ribosomal protein gene promoters, we have constructed a gene fusion between the yeast ribosomal protein gene RP39A and the Escherichia coli lacZ gene. This gene fusion contains approximately 1,030 nucleotides of the 5' flanking region and the first 49 1/3 codons of RP39A fused in frame to a large 3' end fragment of lacZ. Whether it is introduced into yeast cells on a moderately high-copy-number plasmid, or integrated into the yeast genome at the RP39A locus, this RP39A-lacZ gene directs the synthesis of a hybrid transcript which encodes beta-galactosidase activity. Deletions in the 5' flanking region of RP39A-lacZ were constructed by linker insertion and BAL 31 mutagenesis. The expression of the mutant genes in yeast cells was assayed by measuring RP39A-lacZ mRNA and beta-galactosidase levels. By these means we have shown that the sequences between nucleotides -256 and -170 upstream of RP39A are essential for expression of this gene. Three sequence motifs, HOMOL1, RPG, and a T-rich region, which were found in that order 5'----3' upstream of most yeast ribosomal protein genes, were present within this interval. We found that substitution of the CYC1-lacZ upstream activation site with the fragment from nucleotides -298 to -172 upstream of RP39A, containing the HOMOL1-RPG-T-rich motif in that 5'----3' orientation, fully restored expression of the CYC1-lacZ gene. The essentially of HOMOL1, the RPG sequence, and the T-rich region for wild-type levels of expression of RP39A, the conserved location and order of these sequence motifs in yeast ribosomal protein genes, and the ability of a DNA fragment carrying these three sequence elements to substitute for the upstream activation site regions of CYC1 indicate that these three oligonucleotides may be essential to the transcription of yeast ribosomal protein genes.
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PMID:Tripartite upstream promoter element essential for expression of Saccharomyces cerevisiae ribosomal protein genes. 302 62

The relative rates of synthesis of Saccharomyces cerevisiae ribosomal proteins increase coordinately during a nutritional upshift. We constructed a gene fusion which contained 528 base pairs of sequence upstream from and including the TATA box of ribosomal protein gene rp55-1 (S16A-1) fused to a CYC1-lacZ fusion. This fusion was integrated in single copy at the rp55-1 locus in the yeast genome. During a nutritional upshift, in which glucose was added to cells growing in an ethanol-based medium, we found that the increase in the relative rate of synthesis of the beta-galactosidase protein product followed the same kinetics as the change in relative rates of synthesis of several ribosomal proteins measured in the same experiment. This demonstrates that the nontranscribed sequences upstream from the rp55-1 gene, which are present in the fusion, are sufficient to mediate the change in rates of synthesis characteristic of ribosomal proteins under these conditions. The results also suggest that a change in transcription rates is mainly responsible for the increase in relative rates of synthesis of ribosomal proteins during a nutritional upshift in S. cerevisiae.
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PMID:Transcriptional regulation of ribosomal proteins during a nutritional upshift in Saccharomyces cerevisiae. 302 33

We report yeast/Escherichia coli shuttle vectors suitable for fusing yeast promoter and coding sequences to the lacZ gene of E. coli. The vectors contain a region of multiple unique restriction sites including EcoRI, KpnI, SmaI, BamHI, XbaI, SalI, PstI, SphI and HindIII. The region with the unique cloning sites has been introduced in both orientations with respect to lacZ and occurs proximal to the eighth codon of the gene. All the restriction sites have been phased to three different reading frames. Two series of vectors have been constructed. The first series (YEp) has two origins of replication (ori), i.e., of the yeast 2 mu circle and of the ColE1 plasmid of E. coli, and can therefore replicate autonomously in both organisms. These shuttle vectors also have the ApR gene of E. coli and either the yeast LEU2 or URA3 genes to allow for selection of both E. coli and yeast transformants. The second series of vectors (YIp) are identical in all respects to the YEp vectors except that they lack the 2 mu ori. The YIp vectors can be used to integrate lacZ fusions into yeast chromosomal DNA. None of the vectors express beta-galactosidase (beta Gal) in yeast or E. coli in the absence of inserted yeast promoter sequences. The 5'-nontranslated sequences and parts of the coding sequences of various yeast genes have been cloned into representative lacZ fusion vectors. In-frame gene fusions can be detected by beta Gal activity when either yeast or E. coli clones are plated on media containing XGal indicator. Quantitative determinations of promoter activity were made by colorimetric assay of beta Gal activity in whole cells. Fusion of the yeast CYC1 gene to lacZ in one of the vectors allowed detection of regulated expression of this gene when cells were grown under conditions of catabolite repression or derepression.
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PMID:Yeast shuttle and integrative vectors with multiple cloning sites suitable for construction of lacZ fusions. 302 15

In contrast to the Escherichia coli lac operon, the yeast beta-galactosidase gene is positively regulated. In the 5'-noncoding region of the Kluyveromyces lactis LAC4 gene, we mapped an upstream activation site (UAS) that is required for induction. This sequence, located between positions -435 and -326 from the start of translation, functions irrespective of its orientation and can confer lactose regulation to the heterologous CYC1 promoter. It is composed of at least two subsequences that must act in concert. One of these subsequences showed a strong homology to the UAS consensus sequence of the Saccharomyces cerevisiae GAL genes (E. Giniger, S. M. Varnum, and M. Ptashne, Cell 40:767-774, 1985). We propose that this region of homology located at about position -426 is a binding site for the product of the regulatory gene LAC9 which probably induces transcription of the LAC4 gene in a manner analogous to that of the GAL4 protein.
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PMID:Positive regulation of the beta-galactosidase gene from Kluyveromyces lactis is mediated by an upstream activation site that shows homology to the GAL upstream activation site of Saccharomyces cerevisiae. 310 72

The 25S rRNA gene of Saccharomyces cerevisiae is preceded by a bona fide TATA sequence which allows the initiation of transcription--presumably by polymerase II--from the same strand as the 25S rRNA gene. When the promoter fragment is cloned in front of a lacZ gene equipped with an initiation codon but lacking a promoter, this element permits formation of beta-galactosidase both in yeast and E. coli. Using RNA from yeast transformed with the fusion plasmid, we mapped by primer elongation a single initiation site 63 bp downstream from the presumed TATA sequence, i.e. about 53 bp 5' of the 25S rRNA gene. A similar signal at about the same position was observed when RNA from untransformed wild-type yeast was used as a template for primer elongation. These results suggest that transcription from this polymerase II promoter-like element occurs in vivo. A regulatory function could not be assigned to this transcript. Its initiation is not significantly influenced by heme or carbon source, although two boxes of high homology with upstream activation sequences (UAS) mediating heme dependent expression of the iso-1-cytochrome c gene (CYC1) precede the promoter at the appropriate distance.
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PMID:The 5'-upstream region of the yeast 25S rRNA gene contains a promoter element allowing expression in yeast and E. coli. 314 15


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