<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Kaadige, Mohan R</style></author><author><style face="normal" font="default" size="100%">Lopes, John M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Analysis of Opi1p repressor mutants.</style></title><secondary-title><style face="normal" font="default" size="100%">Curr Genet</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Curr. Genet.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Basic Helix-Loop-Helix Transcription Factors</style></keyword><keyword><style  face="normal" font="default" size="100%">Conserved Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation, Missense</style></keyword><keyword><style  face="normal" font="default" size="100%">Myo-Inositol-1-Phosphate Synthase</style></keyword><keyword><style  face="normal" font="default" size="100%">Repressor Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Saccharomyces cerevisiae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcription Factors</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2006 Jan</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">49</style></volume><pages><style face="normal" font="default" size="100%">30-8</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Opi1p is the only known repressor protein specific to the phospholipid biosynthetic pathway. Opi1p is required for repression in response to inositol and choline supplementation. However, the mechanism of Opi1p repression is not completely understood. In part, this is because previously identified opi1 mutants contained nonsense mutations and thus provided little insight into the mechanism of Opi1p function. We have recently reported isolating novel opi1 mutants (rum and dim mutants) that contain missense mutations. Here, we show that these opi1 mutants produce Opi1p product at levels comparable to a wild-type strain. However, these mutants mis-regulate expression of two target genes, INO2-HIS3 and INO1-lacZ, and are also defective in autoregulation. An opi1-S339F mutant is particularly interesting because it completely eliminated autoregulation, but only abated regulation of an INO1-lacZ reporter. Two of the mutations in OPI1 (V343Q and S339F) provide genetic evidence for an interaction between Opi1p and the Ino2p activator since they reside in a region of Opi1p recently shown to interact with Ino2p in vitro. A third mutation (L252F) resides in a region of Opi1p with no known function.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16322993?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gardocki, Mary Elizabeth</style></author><author><style face="normal" font="default" size="100%">Lopes, John M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Expression of the yeast PIS1 gene requires multiple regulatory elements including a Rox1p binding site.</style></title><secondary-title><style face="normal" font="default" size="100%">J Biol Chem</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Biol. Chem.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anoxia</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbon</style></keyword><keyword><style  face="normal" font="default" size="100%">Chloramphenicol O-Acetyltransferase</style></keyword><keyword><style  face="normal" font="default" size="100%">Choline</style></keyword><keyword><style  face="normal" font="default" size="100%">Chromatography, Thin Layer</style></keyword><keyword><style  face="normal" font="default" size="100%">Conserved Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Complementary</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Deletion</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Fungal</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Reporter</style></keyword><keyword><style  face="normal" font="default" size="100%">Inositol</style></keyword><keyword><style  face="normal" font="default" size="100%">Lipid Metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Biological</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxygen</style></keyword><keyword><style  face="normal" font="default" size="100%">Phospholipids</style></keyword><keyword><style  face="normal" font="default" size="100%">Plasmids</style></keyword><keyword><style  face="normal" font="default" size="100%">Promoter Regions, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Binding</style></keyword><keyword><style  face="normal" font="default" size="100%">Repressor Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA</style></keyword><keyword><style  face="normal" font="default" size="100%">Saccharomyces cerevisiae</style></keyword><keyword><style  face="normal" font="default" size="100%">Saccharomyces cerevisiae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcription, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Transferases (Other Substituted Phosphate Groups)</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2003 Oct 3</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">278</style></volume><pages><style face="normal" font="default" size="100%">38646-52</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The PIS1 gene is required for de novo synthesis of phosphatidylinositol (PI), an essential phospholipid in Saccharomyces cerevisiae. PIS1 gene expression is unusual because it is uncoupled from the other phospholipid biosynthetic genes, which are regulated in response to inositol and choline. Relatively little is known about regulation of transcription of the PIS1 gene. We reported previously that PIS1 transcription is sensitive to carbon source. To further our understanding of the regulation of PIS1 transcription, we carried out a promoter deletion analysis that identified three regions required for PIS1 gene expression (upstream activating sequence (UAS) elements 1-3). Deletion of either UAS1 or UAS2 resulted in an approximately 45% reduction in expression, whereas removal of UAS3 yielded an 84% decrease in expression. A comparison of promoters among several Saccharomyces species shows that these sequences are highly conserved. Curiously, the UAS3 element region (-149 to -138) includes a Rox1p binding site. Rox1p is a repressor of hypoxic genes under aerobic growth conditions. Consistent with this, we have found that expression of a PIS1-cat reporter was repressed under aerobic conditions, and this repression was dependent on both Rox1p and its binding site. Furthermore, PI levels were elevated under anaerobic conditions. This is the first evidence that PI levels are affected by regulation of PIS1 transcription.</style></abstract><issue><style face="normal" font="default" size="100%">40</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/12890676?dopt=Abstract</style></custom1></record></records></xml>