scholarly journals Characterization of the DNA-binding activity of GCR1: in vivo evidence for two GCR1-binding sites in the upstream activating sequence of TPI of Saccharomyces cerevisiae.

1992 ◽  
Vol 12 (6) ◽  
pp. 2690-2700 ◽  
Author(s):  
M A Huie ◽  
E W Scott ◽  
C M Drazinic ◽  
M C Lopez ◽  
I K Hornstra ◽  
...  

GCR1 gene function is required for high-level glycolytic gene expression in Saccharomyces cerevisiae. Recently, we suggested that the CTTCC sequence motif found in front of many genes encoding glycolytic enzymes lay at the core of the GCR1-binding site. Here we mapped the DNA-binding domain of GCR1 to the carboxy-terminal 154 amino acids of the polypeptide. DNase I protection studies showed that a hybrid MBP-GCR1 fusion protein protected a region of the upstream activating sequence of TPI (UASTPI), which harbored the CTTCC sequence motif, and suggested that the fusion protein might also interact with a region of the UAS that contained the related sequence CATCC. A series of in vivo G methylation protection experiments of the native TPI promoter were carried out with wild-type and gcr1 deletion mutant strains. The G doublets that correspond to the C doublets in each site were protected in the wild-type strain but not in the gcr1 mutant strain. These data demonstrate that the UAS of TPI contains two GCR1-binding sites which are occupied in vivo. Furthermore, adjacent RAP1/GRF1/TUF- and REB1/GRF2/QBP/Y-binding sites in UASTPI were occupied in the backgrounds of both strains. In addition, DNA band-shift assays were used to show that the MBP-GCR1 fusion protein was able to form nucleoprotein complexes with oligonucleotides that contained CTTCC sequence elements found in front of other glycolytic genes, namely, PGK, ENO1, PYK, and ADH1, all of which are dependent on GCR1 gene function for full expression. However, we were unable to detect specific interactions with CTTCC sequence elements found in front of the translational component genes TEF1, TEF2, and CRY1. Taken together, these experiments have allowed us to propose a consensus GCR1-binding site which is 5'-(T/A)N(T/C)N(G/A)NC(T/A)TCC(T/A)N(T/A)(T/A)(T/G)-3'.

1992 ◽  
Vol 12 (6) ◽  
pp. 2690-2700
Author(s):  
M A Huie ◽  
E W Scott ◽  
C M Drazinic ◽  
M C Lopez ◽  
I K Hornstra ◽  
...  

GCR1 gene function is required for high-level glycolytic gene expression in Saccharomyces cerevisiae. Recently, we suggested that the CTTCC sequence motif found in front of many genes encoding glycolytic enzymes lay at the core of the GCR1-binding site. Here we mapped the DNA-binding domain of GCR1 to the carboxy-terminal 154 amino acids of the polypeptide. DNase I protection studies showed that a hybrid MBP-GCR1 fusion protein protected a region of the upstream activating sequence of TPI (UASTPI), which harbored the CTTCC sequence motif, and suggested that the fusion protein might also interact with a region of the UAS that contained the related sequence CATCC. A series of in vivo G methylation protection experiments of the native TPI promoter were carried out with wild-type and gcr1 deletion mutant strains. The G doublets that correspond to the C doublets in each site were protected in the wild-type strain but not in the gcr1 mutant strain. These data demonstrate that the UAS of TPI contains two GCR1-binding sites which are occupied in vivo. Furthermore, adjacent RAP1/GRF1/TUF- and REB1/GRF2/QBP/Y-binding sites in UASTPI were occupied in the backgrounds of both strains. In addition, DNA band-shift assays were used to show that the MBP-GCR1 fusion protein was able to form nucleoprotein complexes with oligonucleotides that contained CTTCC sequence elements found in front of other glycolytic genes, namely, PGK, ENO1, PYK, and ADH1, all of which are dependent on GCR1 gene function for full expression. However, we were unable to detect specific interactions with CTTCC sequence elements found in front of the translational component genes TEF1, TEF2, and CRY1. Taken together, these experiments have allowed us to propose a consensus GCR1-binding site which is 5'-(T/A)N(T/C)N(G/A)NC(T/A)TCC(T/A)N(T/A)(T/A)(T/G)-3'.


1991 ◽  
Vol 11 (11) ◽  
pp. 5648-5659
Author(s):  
F J McNally ◽  
J Rine

Copies of the mating-type genes are present at three loci on chromosome III of the yeast Saccharomyces cerevisiae. The genes at the MAT locus are transcribed, whereas the identical genes at the silent loci, HML and HMR, are not transcribed. Several genes, including the four SIR genes, and two sites, HMR-E and HMR-I, are required for repression of transcription at the HMR locus. Three elements have been implicated in the function of the HMR-E silencer: a binding site for the RAP1 protein, a binding site for the ABF1 protein, and an 11-bp consensus sequence common to nearly all autonomously replicating sequence (ARS) elements (putative origins of DNA replication). RAP1 and ABF1 binding sites of different sequence than those found at HMR-E were joined with an 11-bp ARS consensus sequence to form a synthetic silencer. The synthetic silencer was able to repress transcription of the HMRa1 gene, confirming that binding sites for RAP1 and ABF1 and the 11-bp ARS consensus sequence were the functional components of the silencer in vivo. Mutations in the ABF1 binding site or in the ARS consensus sequence of the synthetic silencer caused nearly complete derepression of transcription at HMR. The ARS consensus sequence mutation also eliminated the ARS activity of the synthetic silencer. These data suggested that replication initiation at the HMR-E silencer was required for establishment of the repressed state at the HMR locus.


1998 ◽  
Vol 180 (23) ◽  
pp. 6342-6351 ◽  
Author(s):  
Roy Magnuson ◽  
Michael B. Yarmolinsky

ABSTRACT The P1 plasmid addiction operon encodes Doc, a toxin that kills plasmid-free segregants, and Phd, an unstable antidote that neutralizes the toxin. Additionally, these products repress transcription of the operon. The antidote binds to two adjacent sites in the promoter. Here we present evidence concerning the regulatory role of the toxin, which we studied with the aid of a mutation,docH66Y. The DocH66Y protein retained the regulatory properties of the wild-type protein, but not its toxicity. In vivo, DocH66Y enhanced repression by Phd but failed to affect repression in the absence of Phd, suggesting that DocH66Y contacts Phd. In vitro, a MalE-DocH66Y fusion protein was found to bind Phd. Binding of toxin to antidote may be the physical basis for the neutralization of toxin. DocH66Y failed to bind DNA in vitro yet enhanced the affinity, cooperativity, and specificity with which Phd bound the operator. Although DocH66Y enhanced the binding of Phd to two adjacent Phd-binding sites, DocH66Y had relatively little effect on the binding of Phd to a single Phd-binding site, indicating that DocH66Y mediates cooperative interactions between adjacent Phd-binding sites. Several electrophoretically distinct protein-DNA complexes were observed with different amounts of DocH66Y relative to Phd. Maximal repression and specificity of DNA binding were observed with subsaturating amounts of DocH66Y relative to Phd. Analogous antidote-toxin pairs appear to have similar autoregulatory circuits. Autoregulation, by dampening fluctuations in the levels of toxin and antidote, may prevent the inappropriate activation of the toxin.


1991 ◽  
Vol 11 (11) ◽  
pp. 5648-5659 ◽  
Author(s):  
F J McNally ◽  
J Rine

Copies of the mating-type genes are present at three loci on chromosome III of the yeast Saccharomyces cerevisiae. The genes at the MAT locus are transcribed, whereas the identical genes at the silent loci, HML and HMR, are not transcribed. Several genes, including the four SIR genes, and two sites, HMR-E and HMR-I, are required for repression of transcription at the HMR locus. Three elements have been implicated in the function of the HMR-E silencer: a binding site for the RAP1 protein, a binding site for the ABF1 protein, and an 11-bp consensus sequence common to nearly all autonomously replicating sequence (ARS) elements (putative origins of DNA replication). RAP1 and ABF1 binding sites of different sequence than those found at HMR-E were joined with an 11-bp ARS consensus sequence to form a synthetic silencer. The synthetic silencer was able to repress transcription of the HMRa1 gene, confirming that binding sites for RAP1 and ABF1 and the 11-bp ARS consensus sequence were the functional components of the silencer in vivo. Mutations in the ABF1 binding site or in the ARS consensus sequence of the synthetic silencer caused nearly complete derepression of transcription at HMR. The ARS consensus sequence mutation also eliminated the ARS activity of the synthetic silencer. These data suggested that replication initiation at the HMR-E silencer was required for establishment of the repressed state at the HMR locus.


2005 ◽  
Vol 4 (10) ◽  
pp. 1725-1735 ◽  
Author(s):  
Indrani Som ◽  
Rebecca N. Mitsch ◽  
Jennifer L. Urbanowski ◽  
Ronda J. Rolfes

ABSTRACT Expression of the genes in the ADE regulon of Saccharomyces cerevisiae is repressed by the presence of purine bases in the extracellular medium and derepressed when cells are grown in the absence of purines. Derepression requires the transcriptional activators Bas1 and Pho2, as well as the biosynthetic intermediates 5′-phosphoribosyl-4-succinocarboxamide-5-aminoimidazole (SAICAR) and 5′-phosphoribosyl-4-carboxamide- 5-aminoimidazole (AICAR). In this study, we investigated if nuclear localization and binding to promoter DNA by the activators are regulated by purines. Using indirect immunofluorescence, we found that Bas1 is localized to the nucleus under both repressing and derepressing conditions. Importantly, we detected Bas1 bound to promoter DNA under both conditions using chromatin immunoprecipitation assays at several ADE promoters (ADE1, ADE2, ADE4, and ADE5,7) and HIS4. We analyzed the binding of Bas1 to wild-type and mutant sequences of the ADE5,7 promoters in vivo, and found that Bas1 binds independently to each of its two binding sites. Pho2 was not required for the association of Bas1 with chromosomal DNA, but it was required for an increase in Bas1-immunoprecipitated DNA. The presence of Pho2 at promoters was dependent on Bas1 and occurred only under derepressing conditions when the ADE genes are transcribed at elevated levels. We propose a model for regulation of the ADE genes in which DNA-bound Bas1 is inactive due to masking of its activation domain and Pho2 binds poorly to promoters when cells have sufficient purine nucleotides. Upon limitation for purines, the SAICAR/AICAR regulatory signal is transmitted to the nucleus to increase Bas1 and Pho2 interaction, recruiting Pho2 to promoters and freeing the activation domains for transactivation.


1989 ◽  
Vol 9 (7) ◽  
pp. 2914-2921 ◽  
Author(s):  
S S Walker ◽  
S C Francesconi ◽  
B K Tye ◽  
S Eisenberg

The autonomously replicating sequence ARS121 was cloned as a 480-base-pair (bp) long DNA fragment that confers on plasmids autonomous replication in Saccharomyces cerevisiae. This fragment contains two OBF1-binding sites (sites I and II) of different affinities, as identified by a gel mobility shift assay and footprint analysis. Nucleotide substitutions (16 to 18 bp) within either of the two sites obliterated detectable in vitro OBF1 binding to the mutagenized site. Linker substitution (6 bp) mutations within the high-affinity site I showed effects similar to those of the complete substitution, whereas DNA mutagenized outside the binding site bound OBF1 normally. We also tested the mitotic stability of centromeric plasmids bearing wild-type and mutagenized copies of ARS121. Both deletion of the sites and the extensive base alterations within either of the two OBF1-binding sites reduced the percentage of plasmid-containing cells in the population from about 88% to 50 to 63% under selective growth and from about 46% to 15 to 20% after 10 to 12 generations of nonselective growth. Furthermore, linker (6 bp) substitutions within site I, the high-affinity binding site, showed similar deficiencies in plasmid stability. In contrast, plasmids containing linker substitutions in sequences contiguous to site I displayed wild-type stability. In addition, plasmid copy number analysis indicated that the instability probably resulted not from nondisjunction during mitosis but rather from inefficient plasmid replication. The results strongly support the notion that the OBF1-binding sites and the OBF1 protein are important for normal ARS function as an origin of replication.


2002 ◽  
Vol 22 (7) ◽  
pp. 2078-2088 ◽  
Author(s):  
Antonin Morillon ◽  
Lionel Bénard ◽  
Mathias Springer ◽  
Pascale Lesage

ABSTRACT Approximately 30 copies of the Ty1 retrotransposon are present in the genome of Saccharomyces cerevisiae. Previous studies gave insights into the global regulation of Ty1 transcription but provided no information on the behavior of individual genomic elements. This work shows that the expression of 31 individual Ty1 elements in S288C varies over a 50-fold range. Their transcription is repressed by chromatin structures, which are antagonized by the Swi/Snf and SAGA chromatin-modifying complexes in highly expressed Ty1 elements. These elements carry five potential Gcn4 binding sites in their promoter regions that are mostly absent in weakly expressed Ty1 copies. Consistent with this observation, Gcn4 activates the transcription of highly expressed Ty1 elements only. One of the potential Gcn4 binding sites acts as an upstream activating sequence in vivo and interacts with Gcn4 in vitro. Since Gcn4 has been shown to interact with Swi/Snf and SAGA, we predict that Gcn4 activates Ty1 transcription by targeting these complexes to specific Ty1 promoters.


1989 ◽  
Vol 9 (7) ◽  
pp. 2914-2921
Author(s):  
S S Walker ◽  
S C Francesconi ◽  
B K Tye ◽  
S Eisenberg

The autonomously replicating sequence ARS121 was cloned as a 480-base-pair (bp) long DNA fragment that confers on plasmids autonomous replication in Saccharomyces cerevisiae. This fragment contains two OBF1-binding sites (sites I and II) of different affinities, as identified by a gel mobility shift assay and footprint analysis. Nucleotide substitutions (16 to 18 bp) within either of the two sites obliterated detectable in vitro OBF1 binding to the mutagenized site. Linker substitution (6 bp) mutations within the high-affinity site I showed effects similar to those of the complete substitution, whereas DNA mutagenized outside the binding site bound OBF1 normally. We also tested the mitotic stability of centromeric plasmids bearing wild-type and mutagenized copies of ARS121. Both deletion of the sites and the extensive base alterations within either of the two OBF1-binding sites reduced the percentage of plasmid-containing cells in the population from about 88% to 50 to 63% under selective growth and from about 46% to 15 to 20% after 10 to 12 generations of nonselective growth. Furthermore, linker (6 bp) substitutions within site I, the high-affinity binding site, showed similar deficiencies in plasmid stability. In contrast, plasmids containing linker substitutions in sequences contiguous to site I displayed wild-type stability. In addition, plasmid copy number analysis indicated that the instability probably resulted not from nondisjunction during mitosis but rather from inefficient plasmid replication. The results strongly support the notion that the OBF1-binding sites and the OBF1 protein are important for normal ARS function as an origin of replication.


1993 ◽  
Vol 13 (11) ◽  
pp. 6866-6875 ◽  
Author(s):  
D C Hagen ◽  
L Bruhn ◽  
C A Westby ◽  
G F Sprague

Transcription activation of alpha-specific genes in Saccharomyces cerevisiae is regulated by two proteins, MCM1 and alpha 1, which bind to DNA sequences, called P'Q elements, found upstream of alpha-specific genes. Neither MCM1 nor alpha 1 alone binds efficiently to P'Q elements. Together, however, they bind cooperatively in a manner that requires both the P' sequence, which is a weak binding site for MCM1, and the Q sequence, which has been postulated to be the binding site for alpha 1. We analyzed a collection of point mutations in the P'Q element of the STE3 gene to determine the importance of individual base pairs for alpha-specific gene transcription. Within the 10-bp conserved Q sequence, mutations at only three positions strongly affected transcription activation in vivo. These same mutations did not affect the weak binding to P'Q displayed by MCM1 alone. In vitro DNA binding assays showed a direct correlation between the ability of the mutant sequences to form ternary P'Q-MCM1-alpha 1 complexes and the degree to which transcription was activated in vivo. Thus, the ability of alpha 1 and MCM1 to bind cooperatively to P'Q elements is critical for activation of alpha-specific genes. In all natural alpha-specific genes the Q sequence is adjacent to the degenerate side of P'. To test the significance of this geometry, we created several novel juxtapositions of P, P', and Q sequences. When the Q sequence was opposite the degenerate side, the composite QP' element was inactive as a promoter element in vivo and unable to form stable ternary QP'-MCM1-alpha 1 complexes in vitro. We also found that addition of a Q sequence to a strong MCM1 binding site allows the addition of alpha 1 to the complex. This finding, together with the observation that Q-element point mutations affected ternary complex formation but not the weak binding of MCM1 alone, supports the idea that the Q sequence serves as a binding site for alpha 1.


2001 ◽  
Vol 21 (8) ◽  
pp. 2790-2801 ◽  
Author(s):  
James F. Theis ◽  
Carol S. Newlon

ABSTRACT While many of the proteins involved in the initiation of DNA replication are conserved between yeasts and metazoans, the structure of the replication origins themselves has appeared to be different. As typified by ARS1, replication origins inSaccharomyces cerevisiae are <150 bp long and have a simple modular structure, consisting of a single binding site for the origin recognition complex, the replication initiator protein, and one or more accessory sequences. DNA replication initiates from a discrete site. While the important sequences are currently less well defined, metazoan origins appear to be different. These origins are large and appear to be composed of multiple, redundant elements, and replication initiates throughout zones as large as 55 kb. In this report, we characterize two S. cerevisiae replication origins, ARS101 and ARS310, which differ from the paradigm. These origins contain multiple, redundant binding sites for the origin recognition complex. Each binding site must be altered to abolish origin function, while the alteration of a single binding site is sufficient to inactivate ARS1. This redundant structure may be similar to that seen in metazoan origins.


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