<?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%">Benmerzouga, Imaan</style></author><author><style face="normal" font="default" size="100%">Concepción-Acevedo, Jeniffer</style></author><author><style face="normal" font="default" size="100%">Kim, Hee-Sook</style></author><author><style face="normal" font="default" size="100%">Vandoros, Anthula V</style></author><author><style face="normal" font="default" size="100%">Cross, George A M</style></author><author><style face="normal" font="default" size="100%">Klingbeil, Michele M</style></author><author><style face="normal" font="default" size="100%">Li, Bibo</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Trypanosoma brucei Orc1 is essential for nuclear DNA replication and affects both VSG silencing and VSG switching.</style></title><secondary-title><style face="normal" font="default" size="100%">Mol Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Mol. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antigenic Variation</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Replication</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Protozoan</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Silencing</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Protozoan</style></keyword><keyword><style  face="normal" font="default" size="100%">Membrane Glycoproteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Origin Recognition Complex</style></keyword><keyword><style  face="normal" font="default" size="100%">Promoter Regions, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Trypanosoma brucei brucei</style></keyword><keyword><style  face="normal" font="default" size="100%">Variant Surface Glycoproteins, Trypanosoma</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013 Jan</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">87</style></volume><pages><style face="normal" font="default" size="100%">196-210</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Binding of the Origin Recognition Complex (ORC) to replication origins is essential for initiation of DNA replication, but ORC has non-essential functions outside of DNA replication, including in heterochromatic gene silencing and telomere maintenance. Trypanosoma brucei, a protozoan parasite that causes human African trypanosomiasis, uses antigenic variation as a major virulence mechanism to evade the host&amp;#39;s immune attack by expressing its major surface antigen, the Variant Surface Glycoprotein (VSG), in a monoallelic manner. An Orc1/Cdc6 homologue has been identified in T.&amp;thinsp;brucei, but its role in DNA replication has not been directly confirmed and its potential involvement in VSG repression or switching has not been thoroughly investigated. In this study, we show that TbOrc1 is essential for nuclear DNA replication in mammalian-infectious bloodstream and tsetse procyclic forms (BF and PF). Depletion of TbOrc1 resulted in derepression of telomere-linked silent VSGs in both BF and PF, and increased VSG switching particularly through the in situ transcriptional switching mechanism. TbOrc1 associates with telomere repeats but appears to do so independently of two known T.&amp;thinsp;brucei telomere proteins, TbRAP1 and TbTRF. We conclude that TbOrc1 has conserved functions in DNA replication and is also required to control telomere-linked VSG expression and VSG switching.&lt;/p&gt;
</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue></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%">Hong, Yeonchul</style></author><author><style face="normal" font="default" size="100%">Nagamune, Kisaburo</style></author><author><style face="normal" font="default" size="100%">Morita, Yasu S</style></author><author><style face="normal" font="default" size="100%">Nakatani, Fumiki</style></author><author><style face="normal" font="default" size="100%">Ashida, Hisashi</style></author><author><style face="normal" font="default" size="100%">Maeda, Yusuke</style></author><author><style face="normal" font="default" size="100%">Kinoshita, Taroh</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Removal or maintenance of inositol-linked acyl chain in glycosylphosphatidylinositol is critical in trypanosome life cycle.</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%">Acylation</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Cloning, Molecular</style></keyword><keyword><style  face="normal" font="default" size="100%">Glycosylphosphatidylinositols</style></keyword><keyword><style  face="normal" font="default" size="100%">Inositol</style></keyword><keyword><style  face="normal" font="default" size="100%">Life Cycle Stages</style></keyword><keyword><style  face="normal" font="default" size="100%">Membrane Glycoproteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Phosphoric Monoester Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Protozoan Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Messenger</style></keyword><keyword><style  face="normal" font="default" size="100%">Trypanosoma brucei brucei</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 Apr 28</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">281</style></volume><pages><style face="normal" font="default" size="100%">11595-602</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The protozoan parasite Trypanosoma brucei is coated by glycosylphosphatidylinositol (GPI)-anchored proteins. During GPI biosynthesis, inositol in phosphatidylinositol becomes acylated. Inositol is deacylated prior to attachment to variant surface glycoproteins in the bloodstream form, whereas it remains acylated in procyclins in the procyclic form. We have cloned a T. brucei GPI inositol deacylase (GPIdeAc2). In accordance with the acylation/deacylation profile, the level of GPIdeAc2 mRNA was 6-fold higher in the bloodstream form than in the procyclic form. Knockdown of GPIdeAc2 in the bloodstream form caused accumulation of an inositol-acylated GPI, a decreased VSG expression on the cell surface and slower growth, indicating that inositol-deacylation is essential for the growth of the bloodstream form. Overexpression of GPIdeAc2 in the procyclic form caused an accumulation of GPI biosynthetic intermediates lacking inositol-linked acyl chain and decreased cell surface procyclins because of release into the culture medium, indicating that overexpression of GPIdeAc2 is deleterious to the surface coat of the procyclic form. Therefore, the GPI inositol deacylase activity must be tightly regulated in trypanosome life cycle.</style></abstract><issue><style face="normal" font="default" size="100%">17</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16510441?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%">Hong, Yeonchul</style></author><author><style face="normal" font="default" size="100%">Nagamune, Kisaburo</style></author><author><style face="normal" font="default" size="100%">Ohishi, Kazuhito</style></author><author><style face="normal" font="default" size="100%">Morita, Yasu S</style></author><author><style face="normal" font="default" size="100%">Ashida, Hisashi</style></author><author><style face="normal" font="default" size="100%">Maeda, Yusuke</style></author><author><style face="normal" font="default" size="100%">Kinoshita, Taroh</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">TbGPI16 is an essential component of GPI transamidase in Trypanosoma brucei.</style></title><secondary-title><style face="normal" font="default" size="100%">FEBS Lett</style></secondary-title><alt-title><style face="normal" font="default" size="100%">FEBS Lett.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acyltransferases</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Disulfides</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Targeting</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Membrane Glycoproteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Multiprotein Complexes</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Subunits</style></keyword><keyword><style  face="normal" font="default" size="100%">Protozoan Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Trypanosoma brucei brucei</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 23</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">580</style></volume><pages><style face="normal" font="default" size="100%">603-6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Glycosylphosphatidylinositol (GPI) is widely used by eukaryotic cell surface proteins for membrane attachment. De novo synthesized GPI precursors are attached to proteins post-translationally by the enzyme complex, GPI transamidase. TbGPI16, a component of the trypanosome transamidase, shares similarity with human PIG-T. Here, we show that TbGPI16 is the orthologue of PIG-T and an essential component of GPI transamidase by creating a TbGPI16 knockout. TbGPI16 forms a disulfide-linked complex with TbGPI8. A cysteine to serine mutant of TbGPI16 was unable to fully restore the surface expression of GPI-anchored proteins upon transfection into the knockout cells, indicating that its disulfide linkage with TbGPI8 is important for the full transamidase activity.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16405969?dopt=Abstract</style></custom1></record></records></xml>