scholarly journals Analysis of the Saccharomyces cerevisiae mitochondrial COX3 mRNA 5' untranslated leader: translational activation and mRNA processing.

1995 ◽  
Vol 15 (6) ◽  
pp. 3291-3300 ◽  
Author(s):  
G Wiesenberger ◽  
M C Costanzo ◽  
T D Fox
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Replacement ◽  
Mrna Processing ◽  
Start Codon ◽  
Detectable Effect ◽  
Homologous Gene ◽  
Activator Proteins ◽  
Large Deletions ◽  
Translational Activation

We used transformation of yeast mitochondria and homologous gene replacement to study features of the 613-base COX3 mRNA 5' untranslated leader (5'-UTL) required for translational activation by the protein products of the nuclear genes PET54, PET122, and PET494 in vivo. Elimination of the single AUG triplet in the 5'-UTL had no detectable effect on expression, indicating that activator proteins do not work by allowing ribosomes to bypass that AUG. Deletion of the entire 5'-UTL completely prevented translation, suggesting that the activator proteins do not function by antagonizing any other negative element in the 5'-UTL. Removal of the 15 terminal bases from the 5' end of the 5'-UTL did not block activator-dependent translation. The largest internal deletion that did not interfere with translation removed 125 bases from the upstream portion of the leader. However, two large deletions that blocked translation could be reverted to activator-dependent expression by secondary changes in the remaining 5'-UTL sequences, indicating that the original deletions had not removed the translational activator target but only deformed it. Taken together, the deletion mutations and revertants define a region of 151 bases (between positions -480 and -330 relative to the start codon) containing sequences that are sufficient for translational activation when modified slightly. Suppression of the respiratory phenotypes of two 5'-UTL mutations by overexpression of PET54, PET122, and PET494 indicated functional interactions between the leader and the three activator proteins. The mature COX3 mRNA is cleaved from a precursor immediately downstream of the preceding tRNAVal in a fashion resembling mRNA processing in vertebrate mitochondria. Our results indicate that the site of this cleavage in Saccharomyces cerevisiae is determined solely by the position of the tRNA.

Analysis of Saccharomyces cerevisiae his3 transcription in vitro: biochemical support for multiple mechanisms of transcription

1990 ◽  
Vol 10 (6) ◽  
pp. 2832-2839
Author(s):  
A S Ponticelli ◽  
K Struhl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Activation ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Initiation Site ◽  
Activator Proteins ◽  
Nuclear Extracts ◽  
Transcription In Vitro

The promoter region of the Saccharomyces cerevisiae his3 gene contains two TATA elements, TC and TR, that direct transcription initiation to two sites designated +1 and +13. On the basis of differences between their nucleotide sequences and their responsiveness to upstream promoter elements, it has previously been proposed that TC and TR promote transcription by different molecular mechanisms. To begin a study of his3 transcription in vitro, we used S. cerevisiae nuclear extracts together with various DNA templates and transcriptional activator proteins that have been characterized in vivo. We demonstrated accurate transcription initiation in vitro at the sites used in vivo, transcriptional activation by GCN4, and activation by a GAL4 derivative on various gal-his3 hybrid promoters. In all cases, transcription stimulation was dependent on the presence of an acidic activation region in the activator protein. In addition, analysis of promoters containing a variety of TR derivatives indicated that the level of transcription in vitro was directly related to the level achieved in vivo. The results demonstrated that the in vitro system accurately reproduced all known aspects of in vivo his3 transcription that depend on the TR element. However, in striking contrast to his3 transcription in vivo, transcription in vitro yielded approximately 20 times more of the +13 transcript than the +1 transcript. This result was not due to inability of the +1 initiation site to be efficiently utilized in vitro, but rather it reflects the lack of TC function in vitro. The results support the idea that TC and TR mediate transcription from the wild-type promoter by distinct mechanisms.

Molecular genetic analysis of Saccharomyces cerevisiae C1-tetrahydrofolate synthase mutants reveals a noncatalytic function of the ADE3 gene product and an additional folate-dependent enzyme

1990 ◽  
Vol 10 (11) ◽  
pp. 5679-5687
Author(s):  
C K Barlowe ◽  
D R Appling
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Point Mutations ◽  
Gene Replacement ◽  
Molecular Genetic Analysis ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Purine Synthesis

In eucaryotes, 10-formyltetrahydrofolate (formyl-THF) synthetase, 5,10-methenyl-THF cyclohydrolase, and NADP(+)-dependent 5,10-methylene-THF dehydrogenase activities are present on a single polypeptide termed C1-THF synthase. This trifunctional enzyme, encoded by the ADE3 gene in the yeast Saccharomyces cerevisiae, is thought to be responsible for the synthesis of the one-carbon donor 10-formyl-THF for de novo purine synthesis. Deletion of the ADE3 gene causes adenine auxotrophy, presumably as a result of the lack of cytoplasmic 10-formyl-THF. In this report, defined point mutations that affected one or more of the catalytic activities of yeast C1-THF synthase were generated in vitro and transferred to the chromosomal ADE3 locus by gene replacement. In contrast to ADE3 deletions, point mutations that inactivated all three activities of C1-THF synthase did not result in an adenine requirement. Heterologous expression of the Clostridium acidiurici gene encoding a monofunctional 10-formyl-THF synthetase in an ade3 deletion strain did not restore growth in the absence of adenine, even though the monofunctional synthetase was catalytically competent in vivo. These results indicate that adequate cytoplasmic 10-formyl-THF can be produced by an enzyme(s) other than C1-THF synthase, but efficient utilization of that 10-formyl-THF for purine synthesis requires a nonenzymatic function of C1-THF synthase. A monofunctional 5,10-methylene-THF dehydrogenase, dependent on NAD+ for catalysis, has been identified and purified from yeast cells (C. K. Barlowe and D. R. Appling, Biochemistry 29:7089-7094, 1990). We propose that the characteristics of strains expressing full-length but catalytically inactive C1-THF synthase could result from the formation of a purine-synthesizing multienzyme complex involving the structurally unchanged C1-THF synthase and that production of the necessary one-carbon units in these strains is accomplished by an NAD+ -dependent 5,10-methylene-THF dehydrogenase.

scholarly journals Saccharomyces cerevisiae BUR6 encodes a DRAP1/NC2alpha homolog that has both positive and negative roles in transcription in vivo.

1997 ◽  
Vol 17 (4) ◽  
pp. 2057-2065 ◽  
Author(s):  
G Prelich
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Essential Gene ◽  
Nucleotide Sequence Analysis ◽  
Detectable Effect ◽  
Histone Fold ◽  
Histone Fold Domain ◽  
Tata Box Binding Protein ◽  
Mutant Phenotypes ◽  
Carboxy Terminal

BUR3 and BUR6 were identified previously by selecting for mutations that increase transcription from an upstream activating sequence (UAS)-less promoter in Saccharomyces cerevisiae. The bur3-1 and bur6-1 mutations are recessive, increase transcription from a suc2 delta uas allele, and cause other mutant phenotypes, suggesting that Bur3p and Bur6p function as general repressors of the basal transcriptional machinery. The molecular cloning and characterization of BUR3 and BUR6 are presented here. BUR3 is identical to MOT1, a previously characterized essential gene that encodes an ATP-dependent inhibitor of the TATA box-binding protein. Cloning and nucleotide sequence analysis reveals that BUR6 encodes a homolog of DRAP1 (also called NC2alpha), a mammalian repressor of basal transcription. Strains that contain a bur6 null allele are viable but grow extremely poorly, demonstrating that BUR6 is critical for normal cell growth in yeast. The Bur6p histone fold domain is required for function; an extensive nonoverlapping set of deletion alleles throughout the histone fold domain impairs BUR6 function in vivo, whereas mutations in the amino- and carboxy-terminal tails have no detectable effect. BUR6 and BUR3/MOT1 have different functions depending on promoter context: although the bur3-1 and bur6-1 mutations increase transcription from delta uas promoters, they result in reduced transcription from the wild-type GAL1 and GAL10 promoters. This transcriptional defect is due to the inability of the GAL10 UAS to function in bur6-1 strains. The similar phenotypes of bur6 and bur3 (mot1) mutations suggest that Bur6p and Mot1p have related, but not identical, functions in modulating the activity of the general transcription machinery in vivo.

scholarly journals Analysis of Saccharomyces cerevisiae his3 transcription in vitro: biochemical support for multiple mechanisms of transcription.

1990 ◽  
Vol 10 (6) ◽  
pp. 2832-2839 ◽  
Author(s):  
A S Ponticelli ◽  
K Struhl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Activation ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Initiation Site ◽  
Activator Proteins ◽  
Nuclear Extracts ◽  
Transcription In Vitro

The promoter region of the Saccharomyces cerevisiae his3 gene contains two TATA elements, TC and TR, that direct transcription initiation to two sites designated +1 and +13. On the basis of differences between their nucleotide sequences and their responsiveness to upstream promoter elements, it has previously been proposed that TC and TR promote transcription by different molecular mechanisms. To begin a study of his3 transcription in vitro, we used S. cerevisiae nuclear extracts together with various DNA templates and transcriptional activator proteins that have been characterized in vivo. We demonstrated accurate transcription initiation in vitro at the sites used in vivo, transcriptional activation by GCN4, and activation by a GAL4 derivative on various gal-his3 hybrid promoters. In all cases, transcription stimulation was dependent on the presence of an acidic activation region in the activator protein. In addition, analysis of promoters containing a variety of TR derivatives indicated that the level of transcription in vitro was directly related to the level achieved in vivo. The results demonstrated that the in vitro system accurately reproduced all known aspects of in vivo his3 transcription that depend on the TR element. However, in striking contrast to his3 transcription in vivo, transcription in vitro yielded approximately 20 times more of the +13 transcript than the +1 transcript. This result was not due to inability of the +1 initiation site to be efficiently utilized in vitro, but rather it reflects the lack of TC function in vitro. The results support the idea that TC and TR mediate transcription from the wild-type promoter by distinct mechanisms.

scholarly journals Two isoforms of Saccharomyces cerevisiae glutaredoxin 2 are expressed in vivo and localize to different subcellular compartments

2002 ◽  
Vol 364 (3) ◽  
pp. 617-623 ◽  
Author(s):  
José R. PEDRAJAS ◽  
Pablo PORRAS ◽  
Emilia MARTÍNEZ-GALISTEO ◽  
C. Alicia PADILLA ◽  
Antonio MIRANDA-VIZUETE ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Exponential Phase ◽  
Start Codon ◽  
Immunochemical Analysis ◽  
Translation Product ◽  
Differential Processing ◽  
Reading Frame ◽  
Yeast Extract Peptone Dextrose ◽  
Long Form

Glutaredoxin (Grx)2 from Saccharomyces cerevisiae is a member of the two-cysteine (dithiol) subfamily of Grxs involved in the defence against oxidative stress in yeast. Recombinant yeast Grx2p, expressed in Escherichia coli, behaves as a ‘classical’ Grx that efficiently catalyses the reduction of hydroxyethyl disulphide by GSH. Grx2p also catalyses the reduction of GSSG by dihydrolipoamide with even higher efficiency. Western blot analysis of S. cerevisiae crude extracts identifies two isoforms of Grx2p of 15.9 and 11.9kDa respectively. The levels of these two isoforms reach a peak during the exponential phase of growth in normal yeast extract/peptone/dextrose ('YPD') medium, with the long form predominating over the short one. From immunochemical analysis of subcellular fractions, it is shown that both isoforms are present in mitochondria, but only the short one is detected in the cytosolic fraction. On the other hand, only the long form is prominent in microsomes. Mitochondrial isoforms should represent the processed and unprocessed products of an open reading frame (YDR513W), with a putative start codon 99bp upstream of the GRX2 start codon described thus far. These results indicate that GRX2 contains two in-frame start codons, and that translation from the first AUG results in a product that is targeted to mitochondria. The cytosolic form would result either by initiation from the second AUG, or by differential processing of one single translation product.

scholarly journals Non-Canonical G-quadruplexes cause the hCEB1 minisatellite instability in Saccharomyces cerevisiae

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Aurèle Piazza ◽  
Xiaojie Cui ◽  
Michael Adrian ◽  
Frédéric Samazan ◽  
Brahim Heddi ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Structure Function ◽  
Genomic Instability ◽  
Function Analysis ◽  
Structural Features ◽  
Detectable Effect ◽  
Definition Of ◽  
And Function

G-quadruplexes (G4) are polymorphic four-stranded structures formed by certain G-rich nucleic acids in vitro, but the sequence and structural features dictating their formation and function in vivo remains uncertain. Here we report a structure-function analysis of the complex hCEB1 G4-forming sequence. We isolated four G4 conformations in vitro, all of which bear unusual structural features: Form 1 bears a V-shaped loop and a snapback guanine; Form 2 contains a terminal G-triad; Form 3 bears a zero-nucleotide loop; and Form 4 is a zero-nucleotide loop monomer or an interlocked dimer. In vivo, Form 1 and Form 2 differently account for 2/3rd of the genomic instability of hCEB1 in two G4-stabilizing conditions. Form 3 and an unidentified form contribute to the remaining instability, while Form 4 has no detectable effect. This work underscores the structural polymorphisms originated from a single highly G-rich sequence and demonstrates the existence of non-canonical G4s in cells, thus broadening the definition of G4-forming sequences.

scholarly journals Molecular genetic analysis of Saccharomyces cerevisiae C1-tetrahydrofolate synthase mutants reveals a noncatalytic function of the ADE3 gene product and an additional folate-dependent enzyme.

1990 ◽  
Vol 10 (11) ◽  
pp. 5679-5687 ◽  
Author(s):  
C K Barlowe ◽  
D R Appling
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Point Mutations ◽  
Gene Replacement ◽  
Molecular Genetic Analysis ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Purine Synthesis

In eucaryotes, 10-formyltetrahydrofolate (formyl-THF) synthetase, 5,10-methenyl-THF cyclohydrolase, and NADP(+)-dependent 5,10-methylene-THF dehydrogenase activities are present on a single polypeptide termed C1-THF synthase. This trifunctional enzyme, encoded by the ADE3 gene in the yeast Saccharomyces cerevisiae, is thought to be responsible for the synthesis of the one-carbon donor 10-formyl-THF for de novo purine synthesis. Deletion of the ADE3 gene causes adenine auxotrophy, presumably as a result of the lack of cytoplasmic 10-formyl-THF. In this report, defined point mutations that affected one or more of the catalytic activities of yeast C1-THF synthase were generated in vitro and transferred to the chromosomal ADE3 locus by gene replacement. In contrast to ADE3 deletions, point mutations that inactivated all three activities of C1-THF synthase did not result in an adenine requirement. Heterologous expression of the Clostridium acidiurici gene encoding a monofunctional 10-formyl-THF synthetase in an ade3 deletion strain did not restore growth in the absence of adenine, even though the monofunctional synthetase was catalytically competent in vivo. These results indicate that adequate cytoplasmic 10-formyl-THF can be produced by an enzyme(s) other than C1-THF synthase, but efficient utilization of that 10-formyl-THF for purine synthesis requires a nonenzymatic function of C1-THF synthase. A monofunctional 5,10-methylene-THF dehydrogenase, dependent on NAD+ for catalysis, has been identified and purified from yeast cells (C. K. Barlowe and D. R. Appling, Biochemistry 29:7089-7094, 1990). We propose that the characteristics of strains expressing full-length but catalytically inactive C1-THF synthase could result from the formation of a purine-synthesizing multienzyme complex involving the structurally unchanged C1-THF synthase and that production of the necessary one-carbon units in these strains is accomplished by an NAD+ -dependent 5,10-methylene-THF dehydrogenase.

scholarly journals Further evidence that the rna2 mutation of Saccharomyces cerevisiae affects mRNA processing.

1982 ◽  
Vol 2 (10) ◽  
pp. 1205-1211 ◽  
Author(s):  
S Bromley ◽  
L Hereford ◽  
M Rosbash
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Synthesis ◽  
Relative Rate ◽  
Mrna Processing ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Wild Type ◽  
Mature Mrna ◽  
Precursor Rna

The relative rate at which ribosomal protein 51 (rp51) mRNA is synthesized was measured by pulse-labeling cells in vivo with [3H]adenine. Two strains of Saccharomyces cerevisiae were compared: A364A (wild type) and ts368 (rna2), a temperature-sensitive strain in which the level of rp51 mRNA decreases and an intron-containing rp51 precursor RNA increases. When cells were shifted up to the nonpermissive temperature (36 degrees C), the rate of rp51 RNA synthesis was only marginally affected (75% of wild type) by the presence of the rna2 mutation. The precursor RNA was the predominant transcription product at 36 degrees C. This precursor could be converted into RNA equal in size to mature mRNA by further incubation at either 36 or 23 degrees C in the presence of unlabeled adenine. The relative half-life of the rp51 transcripts at 36 degrees C also decreased approximately twofold in ts368 as compared with A364A. All of these data imply that the precursor (intron-containing) RNA is processed inefficiently to mature mRNA and that the rp51 precursor RNA is continuously synthesized and degraded in the mutant strain at 36 degrees C.

scholarly journals Functional Conservation of the Glutamine-Rich Domains of Yeast Gal11 and Human SRC-1 in the Transactivation of Glucocorticoid Receptor Tau 1 in Saccharomyces cerevisiae

2007 ◽  
Vol 28 (3) ◽  
pp. 913-925 ◽  
Author(s):  
Dae-Hwan Kim ◽  
Gwang Sik Kim ◽  
Chul Ho Yun ◽  
Young Chul Lee
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glucocorticoid Receptor ◽  
Transcriptional Activation ◽  
Mutational Analysis ◽  
Mediator Complex ◽  
Dependent Manner ◽  
Activator Proteins ◽  
Functional Conservation

ABSTRACT The yeast Gal11 protein, a component of the Mediator complex, is required for the transcriptional activation of many class II genes as a physiological target of various activator proteins in vivo. In this study, we identified the yeast (Saccharomyces cerevisiae) Mediator complex as a novel coactivator of the transcriptional activity of the glucocorticoid receptor (GR) tau 1 (τ1), the major transcriptional activation domain of the GR. GR τ1 directly interacted with the Mediator complex in vivo and in vitro in a Gal11 module-dependent manner, and the Gal11p subunit interacted directly with GR τ1. Specific amino acid residues within the glutamine-rich (Qr) domain of Gal11p (residues 116 to 277) were essential for its interaction with GR τ1 and GR τ1 transactivity in yeast, as demonstrated by mutational analysis of the Gal11 Qr domain, which is highly conserved among human steroid receptor coactivator (SRC) proteins. A Gal11p variant, mini-Gal11p, comprised of the Mediator association and Qr domains of Gal11p or chimeric mini-Gal11p containing the Qr domain of SRC-1 could potentiate the GR τ1 transactivity in a gal11Δ yeast strain. These results suggest that there is functional conservation between Qr domains of yeast Gal11p and mammalian SRC proteins as direct targets of activator proteins in yeast.

Further evidence that the rna2 mutation of Saccharomyces cerevisiae affects mRNA processing

1982 ◽  
Vol 2 (10) ◽  
pp. 1205-1211
Author(s):  
S Bromley ◽  
L Hereford ◽  
M Rosbash
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Synthesis ◽  
Relative Rate ◽  
Mrna Processing ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Wild Type ◽  
Mature Mrna ◽  
Precursor Rna

The relative rate at which ribosomal protein 51 (rp51) mRNA is synthesized was measured by pulse-labeling cells in vivo with [3H]adenine. Two strains of Saccharomyces cerevisiae were compared: A364A (wild type) and ts368 (rna2), a temperature-sensitive strain in which the level of rp51 mRNA decreases and an intron-containing rp51 precursor RNA increases. When cells were shifted up to the nonpermissive temperature (36 degrees C), the rate of rp51 RNA synthesis was only marginally affected (75% of wild type) by the presence of the rna2 mutation. The precursor RNA was the predominant transcription product at 36 degrees C. This precursor could be converted into RNA equal in size to mature mRNA by further incubation at either 36 or 23 degrees C in the presence of unlabeled adenine. The relative half-life of the rp51 transcripts at 36 degrees C also decreased approximately twofold in ts368 as compared with A364A. All of these data imply that the precursor (intron-containing) RNA is processed inefficiently to mature mRNA and that the rp51 precursor RNA is continuously synthesized and degraded in the mutant strain at 36 degrees C.

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