<?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%">Chandler, Julian</style></author><author><style face="normal" font="default" size="100%">Vandoros, Anthula V</style></author><author><style face="normal" font="default" size="100%">Mozeleski, Brian</style></author><author><style face="normal" font="default" size="100%">Klingbeil, Michele M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Stem-loop silencing reveals that a third mitochondrial DNA polymerase, POLID, is required for kinetoplast DNA replication in trypanosomes.</style></title><secondary-title><style face="normal" font="default" size="100%">Eukaryot Cell</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Eukaryotic Cell</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Replication</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Kinetoplast</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Directed DNA Polymerase</style></keyword><keyword><style  face="normal" font="default" size="100%">Mitochondria</style></keyword><keyword><style  face="normal" font="default" size="100%">Mitochondrial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Protozoan Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA Interference</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Double-Stranded</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%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008 Dec</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">7</style></volume><pages><style face="normal" font="default" size="100%">2141-6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Kinetoplast DNA (kDNA), the mitochondrial genome of trypanosomes, is a catenated network containing thousands of minicircles and tens of maxicircles. The topological complexity dictates some unusual features including a topoisomerase-mediated release-and-reattachment mechanism for minicircle replication and at least six mitochondrial DNA polymerases (Pols) for kDNA transactions. Previously, we identified four family A DNA Pols from Trypanosoma brucei with similarity to bacterial DNA Pol I and demonstrated that two (POLIB and POLIC) were essential for maintaining the kDNA network, while POLIA was not. Here, we used RNA interference to investigate the function of POLID in procyclic T. brucei. Stem-loop silencing of POLID resulted in growth arrest and the progressive loss of the kDNA network. Additional defects in kDNA replication included a rapid decline in minicircle and maxicircle abundance and a transient accumulation of minicircle replication intermediates before loss of the kDNA network. These results demonstrate that POLID is a third essential DNA Pol required for kDNA replication. While other eukaryotes utilize a single DNA Pol (Pol gamma) for replication of mitochondrial DNA, T. brucei requires at least three to maintain the complex kDNA network.</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/18849470?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%">Klingbeil, Michele M</style></author><author><style face="normal" font="default" size="100%">Motyka, Shawn A</style></author><author><style face="normal" font="default" size="100%">Englund, Paul T</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Multiple mitochondrial DNA polymerases in Trypanosoma brucei.</style></title><secondary-title><style face="normal" font="default" size="100%">Mol Cell</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Mol. Cell</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%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Kinetoplast</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Directed DNA Polymerase</style></keyword><keyword><style  face="normal" font="default" size="100%">Mitochondria</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Structure, Tertiary</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Double-Stranded</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Messenger</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Homology, Amino Acid</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%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">10</style></volume><pages><style face="normal" font="default" size="100%">175-86</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Kinetoplast DNA (kDNA), the unusual mitochondrial DNA of Trypanosoma brucei, is a network containing thousands of catenated circles. Database searching for a kDNA replicative polymerase (pol) revealed no mitochondrial pol gamma homolog. Instead, we identified four proteins (TbPOLIA, IB, IC, and ID) related to bacterial pol I. Remarkably, all four localized to the mitochondrion. TbPOLIB and TbPOLIC localized beside the kDNA where replication occurs, and their knockdown by RNA interference caused kDNA network shrinkage. Furthermore, silencing of TbPOLIC caused loss of both minicircles and maxicircles and accumulation of minicircle replication intermediates, consistent with a role in replication. While typical mitochondria contain one DNA polymerase, pol gamma, trypanosome mitochondria contain five such enzymes, including the previously characterized pol beta.</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/12150917?dopt=Abstract</style></custom1></record></records></xml>