<?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></records></xml>