@article {1456,
	title = {Saccharomyces cerevisiae essential genes with an Opi- phenotype.},
	journal = {G3 (Bethesda)},
	volume = {4},
	year = {2014},
	month = {2014 Apr},
	pages = {761-7},
	abstract = {<p>The overproduction and secretion of inositol (i.e., Opi(-)) phenotype is associated with defects in regulation of phospholipid biosynthesis in yeast. Here we report a screen of the essential yeast gene set using a conditional-expression library. This screen identified novel functions previously unknown to affect phospholipid synthesis.</p>
},
	keywords = {Cluster Analysis, Genes, Essential, Histone Acetyltransferases, Inositol, Phenotype, Phospholipids, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins},
	issn = {2160-1836},
	doi = {10.1534/g3.113.010140},
	author = {Salas-Santiago, Bryan and Lopes, John M}
}
@article {37,
	title = {Genomic analysis of the Opi- phenotype.},
	journal = {Genetics},
	volume = {173},
	year = {2006},
	month = {2006 Jun},
	pages = {621-34},
	abstract = {Most of the phospholipid biosynthetic genes of Saccharomyces cerevisiae are coordinately regulated in response to inositol and choline. Inositol affects the intracellular levels of phosphatidic acid (PA). Opi1p is a repressor of the phospholipid biosynthetic genes and specifically binds PA in the endoplasmic reticulum. In the presence of inositol, PA levels decrease, releasing Opi1p into the nucleus where it represses transcription. The opi1 mutant overproduces and excretes inositol into the growth medium in the absence of inositol and choline (Opi(-) phenotype). To better understand the mechanism of Opi1p repression, the viable yeast deletion set was screened to identify Opi(-) mutants. In total, 89 Opi(-) mutants were identified, of which 7 were previously known to have the Opi(-) phenotype. The Opi(-) mutant collection included genes with roles in phospholipid biosynthesis, transcription, protein processing/synthesis, and protein trafficking. Included in this set were all nonessential components of the NuA4 HAT complex and six proteins in the Rpd3p-Sin3p HDAC complex. It has previously been shown that defects in phosphatidylcholine synthesis (cho2 and opi3) yield the Opi(-) phenotype because of a buildup of PA. However, in this case the Opi(-) phenotype is conditional because PA can be shuttled through a salvage pathway (Kennedy pathway) by adding choline to the growth medium. Seven new mutants present in the Opi(-) collection (fun26, kex1, nup84, tps1, mrpl38, mrpl49, and opi10/yol032w) were also suppressed by choline, suggesting that these affect PC synthesis. Regulation in response to inositol is also coordinated with the unfolded protein response (UPR). Consistent with this, several Opi(-) mutants were found to affect the UPR (yhi9, ede1, and vps74).},
	keywords = {Gene Expression Regulation, Fungal, Genes, Fungal, Genes, Reporter, Genome, Fungal, Genomics, Inositol, Lac Operon, Models, Biological, Mutation, Phenotype, Phospholipids, Protein Folding, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins},
	issn = {0016-6731},
	doi = {10.1534/genetics.106.057489},
	author = {Hancock, Leandria C and Behta, Ryan P and Lopes, John M}
}
@article {39,
	title = {Phosphatidylinositol biosynthesis: biochemistry and regulation.},
	journal = {Biochim Biophys Acta},
	volume = {1735},
	year = {2005},
	month = {2005 Jul 15},
	pages = {89-100},
	abstract = {Phosphatidylinositol (PI) is a ubiquitous membrane lipid in eukaryotes. It is becoming increasingly obvious that PI and its metabolites play a myriad of very diverse roles in eukaryotic cells. The Saccharomyces cerevisiae PIS1 gene is essential and encodes PI synthase, which is required for the synthesis of PI. Recently, PIS1 expression was found to be regulated in response to carbon source and oxygen availability. It is particularly significant that the promoter elements required for these responses are conserved evolutionarily throughout the Saccharomyces genus. In addition, several genome-wide strategies coupled with more traditional screens suggest that several other factors regulate PIS1 expression. The impact of regulating PIS1 expression on PI synthesis will be discussed along with the possible role(s) that this may have on diseases such as cancer.},
	keywords = {Eukaryotic Cells, Gene Expression Regulation, Fungal, Mutation, Phenotype, Phosphatidylinositols, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transferases (Other Substituted Phosphate Groups)},
	issn = {0006-3002},
	doi = {10.1016/j.bbalip.2005.05.006},
	author = {Gardocki, Mary E and Jani, Niketa and Lopes, John M}
}
@article {41,
	title = {Identification of novel dominant INO2c mutants with an Opi- phenotype.},
	journal = {Mol Microbiol},
	volume = {52},
	year = {2004},
	month = {2004 Jun},
	pages = {1271-80},
	abstract = {The INO2 gene of Saccharomyces cerevisiae is required for derepression of the phospholipid biosynthetic genes in response to inositol depletion. Conversely, the OPI1 gene is required for repression in response to inositol supplementation. Results of an in vitro assay have led to a model in which Opi1p interacts with Ino2p. However, there is no in vivo evidence to support this model. Additionally, most of the previously isolated ino2 mutants offer little insight into this model. Here, we report the isolation of a new class of dominant mutations in the INO2 gene, which yield constitutive expression of a target gene (i.e. an Opi(-) mutant phenotype). Two mutations reside in a region of the Ino2p required for interaction with Opi1p in vitro. Three other mutations are at the amino-terminus in a transcriptional activation domain.},
	keywords = {Basic Helix-Loop-Helix Transcription Factors, Gene Expression Regulation, Fungal, Inositol, Mutation, Phenotype, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors},
	issn = {0950-382X},
	doi = {10.1111/j.1365-2958.2004.04069.x},
	author = {Gardenour, Kyle R and Levy, Jamie and Lopes, John M}
}
@article {43,
	title = {Opi1p, Ume6p and Sin3p control expression from the promoter of the INO2 regulatory gene via a novel regulatory cascade.},
	journal = {Mol Microbiol},
	volume = {48},
	year = {2003},
	month = {2003 May},
	pages = {823-32},
	abstract = {The INO2 gene of Saccharomyces cerevisiae is required for expression of most of the phospholipid biosynthetic genes. INO2 expression is regulated by a complex cascade that includes autoregulation, Opi1p-mediated repression and Ume6p-mediated activation. To screen for mutants with altered INO2 expression directly, we constructed an INO2-HIS3 reporter that provides a plate assay for INO2 promoter activity. This reporter was used to isolate mutants (dim1) that fail to repress expression of the INO2 gene in an otherwise wild-type strain. The dim1 mutants contain mutations in the OPI1 gene. To define further the mechanism for Ume6p regulation of INO2 expression, we isolated suppressors (rum1, 2, 3) of the ume6Delta mutation that overexpress the INO2-HIS3 gene. Two of the rum mutant groups contain mutations in the OPI1 and SIN3 genes showing that opi1 and sin3 mutations are epistatic to the ume6Delta mutation. These results are surprising given that Ume6p, Sin3p and Rpd3p are known to form a complex that represses the expression of a diverse set of yeast genes. This prompted us to examine the effect of sin3Delta and rpd3Delta mutants on INO2-cat expression. Surprisingly, the sin3Delta allele overexpressed INO2-cat, whereas the rpd3Delta mutant had no effect. We also show that the UME6 gene does not affect the expression of an OPI1-cat reporter. This suggests that Ume6p does not regulate INO2 expression indirectly by regulating OPI1 expression.},
	keywords = {Basic Helix-Loop-Helix Transcription Factors, DNA-Binding Proteins, Fungal Proteins, Gene Expression Regulation, Fungal, Genes, Regulator, Genes, Reporter, Genetic Complementation Test, Histone Deacetylases, Methyltransferases, Phenotype, Phospholipids, Promoter Regions, Genetic, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors},
	issn = {0950-382X},
	author = {Kaadige, Mohan R and Lopes, John M}
}
