A comparative analysis of the genetic switch between not-so-distant cousins: versus

Rubio‐Texeira, Marta

doi:10.1016/j.femsyr.2005.05.003

Cited by 81 publications

(81 citation statements)

References 139 publications

(222 reference statements)

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“…This is typically carried out by genetic switches that either activate or repress the transcription of a specific subset of genes. One example is the well-studied GAL gene switch that is used by Saccharomyces cerevisiae (Sc) and Kluyveromyces lactis (Kl ) and related yeasts to adapt to the presence of galactose, melibiose, and lactose by activating the expression of the GAL genes that encode enzymes for metabolizing these carbon sources (Johnston 1987;Lohr et al 1995;Zenke et al 1996;Rubio-Texeira 2005;Sellick and Reece 2005).…”

Section: Socmentioning

confidence: 99%

Intragenic Suppression of Gal3C Interaction With Gal80 in the Saccharomyces cerevisiae GAL Gene Switch

Diep

Peng²,

Bewley

et al. 2006

Genetics

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Gal4-mediated activation of GAL gene transcription in Saccharomyces cerevisiae requires the interaction of Gal3 with Gal80, the Gal4 inhibitor protein. While it is known that galactose and ATP activates Gal3 interaction with Gal80, neither the mechanism of activation nor the surface that binds to Gal80 is known. We addressed this through intragenic suppression of GAL3 C alleles that cause galactose-independent Gal3-Gal80 interaction. We created a new allele, GAL3 SOC , and showed that it suppressed a new GAL3 C allele. We tested the effect of GAL3 SOC on several newly isolated and existing GAL3 C alleles that map throughout the gene. All except one GAL3 C allele, D368V, were suppressible by GAL3 SOC. GAL3 SOC and all GAL3 C alleles were localized on a Gal3 homology model that is based on the structure of the highly related Gal1 protein. These results provide evidence for allosterism in the galactose-and ATP-activation of Gal3 binding to Gal80. In addition, because D368V and residues corresponding to Gal80-nonbinder mutations colocalized to a domain that is absent in homologous proteins that do not bind to Gal80, we suggest that D368 is a part of the Gal80-binding surface.

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Section: Socmentioning

confidence: 99%

Intragenic Suppression of Gal3C Interaction With Gal80 in the Saccharomyces cerevisiae GAL Gene Switch

Diep

Peng²,

Bewley

et al. 2006

Genetics

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“…The Cyc8-Tup1 complex functions as a transcriptional corepressor by interacting with genespecific DNA-binding repressors such as Mig1, Rox1, and a2 (Smith and Johnson 2000). The Cyc8-Tup1 complex represses >150 genes, including FLO1, MATa-specific genes (STE2, STE6, MFA1, and MFA2), and GAL genes (GAL1, GAL3, and GAL4) (DeRisi et al 1997;Smith and Johnson 2000;Rubio-Texeira 2005). The Cyc8-Tup1 complex mediates the formation of a compact repressive chromatin structure through its interaction with multiple transcriptional regulators-including HDAC (histone deacetylase) and histones-which prevents access of TBP and polymerase II (Pol II) to the promoter (Malave and Dent 2006).…”

mentioning

confidence: 99%

Phosphoinositide [PI(3,5)P₂] lipid-dependent regulation of the general transcriptional regulator Tup1

Han

Emr²

2011

Genes Dev.

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Transcriptional activity of a gene is governed by transcriptional regulatory complexes that assemble/disassemble on the gene and control the chromatin architecture. How cytoplasmic components influence the assembly/ disassembly of transcriptional regulatory complexes is poorly understood. Here we report that the budding yeast Saccharomyces cerevisiae has a chromatin architecture-modulating mechanism that is dependent on the endosomal lipid PI(3,5)P 2 . We identified Tup1 and Cti6 as new, highly specific PI(3,5)P 2 interactors. Tup1-which associates with multiple transcriptional regulators, including the HDAC (histone deacetylase) and SAGA complexes-plays a crucial role in determining an activated or repressed chromatin state of numerous genes, including GAL1. We show that, in the context that the Gal4 activation pathway is compromised, PI(3,5)P 2 plays an essential role in converting the Tup1-driven repressed chromatin structure into a SAGA-containing activated chromatin structure at the GAL1 promoter. Biochemical and cell biological experiments suggest that PI(3,5)P 2 recruits Cti6 and the Cyc8-Tup1 corepressor complex to the late endosomal/vacuolar membrane and mediates the assembly of a Cti6-Cyc8-Tup1 coactivator complex that functions to recruit the SAGA complex to the GAL1 promoter. Our findings provide important insights toward understanding how the chromatin architecture and epigenetic status of a gene are regulated by cytoplasmic components.[Keywords: PI(3,5)P 2 lipid; Cti6-Cyc8-Tup1; GAL1 transcriptional induction; lysosomal vacuolar endosome]

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“…The S. cerevisiae GAL regulon has become a paradigm for transcriptional control in lower eukaryotes and a model system for gene regulation (1)(2)(3). Although its importance is uncontested, the present results illustrate that this regulatory network may be restricted to yeasts and not representative for other ascomycetous fungi in general.…”

Section: Discussionmentioning

confidence: 73%

“…This allows the transcriptional activator ScGal4 to recruit the RNA polymerase II to each of the GAL genes (reviewed in Refs. [1][2][3].…”

mentioning

confidence: 99%

Induction of the gal Pathway and Cellulase Genes Involves No Transcriptional Inducer Function of the Galactokinase in Hypocrea jecorina

Hartl

Kubicek

Schink

2007

Journal of Biological Chemistry

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The Saccharomyces cerevisiae galactokinase ScGal1, a key enzyme for D-galactose metabolism, catalyzes the conversion of D-galactose to D-galactose 1-phosphate, whereas its catalytically inactive paralogue, ScGal3, activates the transcription of the GAL pathway genes. In Kluyveromyces lactis the transcriptional inducer function and the galactokinase activity are encoded by a single bifunctional KlGal1. Here, we investigated the cellular function of the single galactokinase GAL1 in the multicellular ascomycete Hypocrea jecorina ‫؍(‬ Trichoderma reesei) in the induction of the gal genes and of the galactokinase-dependent induction of the cellulase genes by lactose (1,4-O-␤-D-galactopyranosyl-D-glucose). A comparison of the transcriptional response of a strain deleted in the gal1 gene (no putative transcriptional inducer and no galactokinase activity), a strain expressing a catalytically inactive GAL1 version (no galactokinase activity but a putative inducer function), and a strain expressing the Escherichia coli galK (no putative transcriptional inducer but galactokinase activity) showed that, in contrast to the two yeasts, both the GAL1 protein and the galactokinase activity are fully dispensable for induction of the Leloir pathway gene gal7 by D-galactose and that only the galactokinase activity is required for cellulase induction by lactose. The data document a fundamental difference in the mechanisms by which yeasts and multicellular fungi respond to the presence of D-galactose, showing that the Gal1/Gal3-Gal4 -Gal80-dependent regulatory circuit does not operate in multicellular fungi.The enzymes of the Leloir pathway are responsible for the conversion of D-galactose to D-glucose 1-phosphate and have been identified in all biological kingdoms. In the model organism Saccharomyces cerevisiae, the genes encoding the three main Leloir pathway enzymes, GAL1 (galactose kinase), GAL7 (UDP-galactose uridylyltransferase), and GAL10 (UDP-galactose epimerase and aldose 1-epimerase), are clustered and coordinately regulated at the level of transcription. The S. cerevisiae GAL genes are repressed by D-glucose, expressed only at a very low basal level on other respiratory carbon sources, and highly induced (up to 1000-fold) when the cells are switched to a medium containing D-galactose. This transcriptional activation is mediated by the interplay of three proteins; in the presence of D-galactose and ATP, the transcriptional inducer ScGal3 associates with the ScGal80 repressor thereby alleviating its repressing effects. This allows the transcriptional activator ScGal4 to recruit the RNA polymerase II to each of the GAL genes (reviewed in Refs.1-3).The S. cerevisiae galactokinase ScGal1 displays a 73% amino acid identity to the ScGal3, but galactokinase activity is absent in ScGal3. However ScGal3 can be converted into a catalytically active galactokinase through the insertion of the two amino acids, Ser and Ala, into its sequence (4). Overexpression of ScGal1, or a phenomenon termed long-term adaptation, can recover a gal3 ph...

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A comparative analysis of the genetic switch between not-so-distant cousins: versus

Cited by 81 publications

References 139 publications

Intragenic Suppression of Gal3C Interaction With Gal80 in the Saccharomyces cerevisiae GAL Gene Switch

Intragenic Suppression of Gal3C Interaction With Gal80 in the Saccharomyces cerevisiae GAL Gene Switch

Phosphoinositide [PI(3,5)P₂] lipid-dependent regulation of the general transcriptional regulator Tup1

Induction of the gal Pathway and Cellulase Genes Involves No Transcriptional Inducer Function of the Galactokinase in Hypocrea jecorina

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A comparative analysis of the genetic switch between not-so-distant cousins: versus

Cited by 81 publications

References 139 publications

Intragenic Suppression of Gal3C Interaction With Gal80 in the Saccharomyces cerevisiae GAL Gene Switch

Intragenic Suppression of Gal3C Interaction With Gal80 in the Saccharomyces cerevisiae GAL Gene Switch

Phosphoinositide [PI(3,5)P2] lipid-dependent regulation of the general transcriptional regulator Tup1

Induction of the gal Pathway and Cellulase Genes Involves No Transcriptional Inducer Function of the Galactokinase in Hypocrea jecorina

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Phosphoinositide [PI(3,5)P₂] lipid-dependent regulation of the general transcriptional regulator Tup1