Identification of AAS genes and their regulatory role in general control of amino acid biosynthesis in yeast.

Penn, M D; Galgoci, Bernie; Greer, Helen

doi:10.1073/pnas.80.9.2704

Cited by 98 publications

(61 citation statements)

References 31 publications

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“…We also plated the cells on medium containing 3-aminotriazole (3-AT), which mimics histidine starvation. Strains carrying ADA2 or GCN5 deletions are defective for growth on medium containing 3-AT due to poor expression of the HIS3 gene (38,44). Figure 2B shows that the gcn5⌬ and ada2⌬ strains used in this study grow poorly on 3-AT compared to the wild type, demonstrating that these strains are exhibiting previously published phenotypes.…”

Section: Nua3 Interacts With Chromatin In Vivosupporting

confidence: 57%

Methylation of Histone H3 Mediates the Association of the NuA3 Histone Acetyltransferase with Chromatin

Martin

Grimes

Baetz

et al. 2006

Molecular and Cellular Biology

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The SAS3-dependent NuA3 histone acetyltransferase complex was originally identified on the basis of its ability to acetylate histone H3 in vitro. Whether NuA3 is capable of acetylating histones in vivo, or how the complex is targeted to the nucleosomes that it modifies, was unknown. To address this question, we asked whether NuA3 is associated with chromatin in vivo and how this association is regulated. With a chromatin pulldown assay, we found that NuA3 interacts with the histone H3 amino-terminal tail, and loss of the H3 tail recapitulates phenotypes associated with loss of SAS3. Moreover, mutation of histone H3 lysine 14, the preferred site of acetylation by NuA3 in vitro, phenocopies a unique sas3⌬ phenotype, suggesting that modification of this residue is important for NuA3 function. The interaction of NuA3 with chromatin is dependent on the Set1p and Set2p histone methyltransferases, as well as their substrates, histone H3 lysines 4 and 36, respectively. These results confirm that NuA3 is functioning as a histone acetyltransferase in vivo and that histone H3 methylation provides a mark for the recruitment of NuA3 to nucleosomes.In eukaryotes, DNA is packaged into chromatin, a nucleoprotein structure consisting of DNA, histones, and nonhistone proteins. The assembly of DNA into chromatin modulates the access of cellular machinery to DNA and thus regulates transcription, replication, repair, and recombination. Chromatin structure can be regulated by the addition of posttranslational modifications to histones, including acetylation, methylation, phosphorylation, and ubiquitination. Consistent with this, several histone posttranslational modifications have been linked to the regulation of gene expression.Numerous multiprotein complexes are involved in the posttranslational modification of histones. These complexes vary in both their protein components and the modifications they effect. The most well-studied group of modifying complexes is the histone acetyltransferases (HATs), which use acetyl coenzyme A as a substrate for the acetylation of lysine residues within both the tail and globular domains of histones (39,43,45,73). In the budding yeast Saccharomyces cerevisiae, there are at least eight proteins that have been identified as having HAT activity in vitro, including Gcn5p, Hat1p, Esa1p, Elp3p, Nut1p, Hpa2p, Sas2p, and Sas3p (45,73), although for many of these proteins, whether histones represent their true substrates in vivo is not known. Three of these proteins are found in complexes that specifically acetylate the lysines within the tail of histone H3, including the GCN5-dependent SAGA, SLIK/ SALSA, ADA, and HAT-A2 complexes (12,16,49,58,60), the ELP3-dependent elongator complex (70), and the SAS3-dependent NuA3 complex (25). The acetylation of histone tails is associated with regions of transcriptional activity, and histone acetylation is thought to modulate chromatin structure through two different mechanisms. First, the neutralization of charge associated with histone acetylation is believed to re...

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Section: Nua3 Interacts With Chromatin In Vivosupporting

confidence: 57%

Methylation of Histone H3 Mediates the Association of the NuA3 Histone Acetyltransferase with Chromatin

Martin

Grimes

Baetz

et al. 2006

Molecular and Cellular Biology

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“…Some of the sequential deletion mutations were also introduced into yeast strain KY498, which contains a gcn4 mutation and hence is unable to induce transcription in response to amino acid starvation (7,12). The phenotypic pattern of the various his3 deletions in the gcn4-2 strain resembled that observed for constitutive expression ( Small deletions of the proximal TGACTC element abolish inducibility.…”

Section: Resultsmentioning

confidence: 99%

Two related regulatory sequences are required for maximal induction of Saccharomyces cerevisiae his3 transcription.

Struhl¹,

Hill²

1987

Mol. Cell. Biol.

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In Saccharomyces cerevisiae, the coordinate induction of his3 and other amino acid biosynthesis genes is mediated by the binding of GCN4 activator protein to specific promoter sequences. The his3 regulatory region contains the sequence TGACTC, which with some variation is repeated six times upstream of the mRNA initiation site. The requirements for maximal his3 induction were examined with a series of sequential 5' deletion mutations as well as a set of small internal deletions. Deletions encroaching as far downstream as position -142 behave indistinguishably from the wild-type gene, thus indicating that the two proximal copies of the regulatory sequence are sufficient for maximal induction. Deletions with breakpoints between -137 and -99 confer inducibility, but not to the normal wild-type level. A deletion ending immediately upstream of the proximal TGACTC sequence (position -99) shows some constitutive expression that is independent of the gcn4 gene product. Deletions extending to -94 or beyond do not produce detectable levels of his3 mRNA. Small internal deletions that only remove the proximal regulatory sequence and a 1-base-pair deletion of the thymine residue at -99 abolish induction, but do not affect the basal level of transcription. These results indicate that the proximal copy between -99 and -94 is absolutely required for his3 induction, whereas the copy between -142 and -137 is required only for the maximal level of induction and is inactive by itself. From these and other observations, we suggest the possibility that these related regulatory sequences may be targets for two distinct proteins.

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“…In Saccharomyces cerevisiae, transcription of a large number of unlinked genes encoding amino acid biosynthetic enzymes is stimulated by the GCN4 protein in response to starvation for any single amino acid (1)(2)(3). This response is attributable to increased expression of GCN4 in starvation conditions.…”

mentioning

confidence: 99%

A segment of GCN4 mRNA containing the upstream AUG codons confers translational control upon a heterologous yeast transcript.

Mueller¹,

Harashima²,

Hinnebusch³

1987

Proc. Natl. Acad. Sci. U.S.A.

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GCN4 encodes a transcriptional activator in Saccharomyces cerevisiae that is regulated at the translational level. We show that an "240-nucleotide segment from the GCN4 mRNA leader containing four AUG codons is sufficient to confer translational control typical of GCN4 upon a GALIlacZ fusion transcript. Regulation of the hybrid transcript is dependent upon multiple positive (GCN) and negative (GCD) trans-acting factors shown to regulate GCN4 expression posttranscriptionally. This result limits the target sequences for these factors to a small internal segment of the GCN4 mRNA leader. The elimination of AUG codons within this segment substantially reduces the usual derepressing effect of mutations in five GCD genes upon GCN4-lacZ expression. This supports the idea that the products of these negative regulatory genes act by modulating the effects of the upstream AUG codons on translation of GCN4 mRNA.In Saccharomyces cerevisiae, transcription of a large number of unlinked genes encoding amino acid biosynthetic enzymes is stimulated by the GCN4 protein in response to starvation for any single amino acid (1-3). This response is attributable to increased expression of GCN4 in starvation conditions. Derepression of GCN4 is dependent upon the trans-acting positive effectors GCN2 and GCN3. Repression of GCN4 in nonstarvation conditions requires the products of multiple GCD genes (4, 5). Genetic evidence suggests that GCN2 and GCN3 act indirectly as positive effectors of GCN4 by negative regulation of GCD factors (1,(5)(6)(7).The leader of GCN4 mRNA contains four AUG codons, each of which initiates a short open reading frame of two or three codons. Removal of all four upstream AUG codons leads to constitutive derepression of GCN4 and bypasses the usual requirement for GCN2 and GCN3 for efficient GCN4 expression. A gcdl mutation leads to little additional derepression of GCN4 expression after removal of the upstream AUG codons. These findings suggest that GCN2, GCN3, and GCDJ regulate GCN4 by modulating the inhibitory effects of the upstream AUG codons on translation of GCN4 mRNA (4, 8-10). Four additional GCD genes are known to act as negative effectors of GCN4 expression (5), but their possible involvement in translational control of GCN4 has not been examined.The upstream AUG codons are located in an ="220-nucleotide internal segment of the "600-nucleotide GCN4 mRNA leader. We were interested in whether other sequences in the GCN4 transcript are required in conjunction with the upstream AUG codons for translational control. To address this possibility, we attempted to transfer the regulation characteristic of GCN4 to a heterologous yeast mRNA by inserting various segments from the GCN4 mRNA leader into the 5' untranslated region of a GALI-lacZ fusion transcript. Our results indicate that an -240-nucleotide leader segment containing the four AUG codons is sufficient to confer general amino acid control upon GALJ-lacZ mRNA. Expression of fusion enzyme from the hybrid transcript is regulated by GCN2, GCN3, and fiv...

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Identification of AAS genes and their regulatory role in general control of amino acid biosynthesis in yeast.

Cited by 98 publications

References 31 publications

Methylation of Histone H3 Mediates the Association of the NuA3 Histone Acetyltransferase with Chromatin

Methylation of Histone H3 Mediates the Association of the NuA3 Histone Acetyltransferase with Chromatin

Two related regulatory sequences are required for maximal induction of Saccharomyces cerevisiae his3 transcription.

A segment of GCN4 mRNA containing the upstream AUG codons confers translational control upon a heterologous yeast transcript.

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