@article {2372,
	title = {Cell cycle localization dynamics of mitochondrial DNA polymerase IC in African trypanosomes.},
	journal = {Mol Biol Cell},
	volume = {29},
	year = {2018},
	month = {10/2018},
	pages = {2540-2552},
	abstract = {<p>Trypanosoma brucei has a unique catenated mitochondrial DNA (mtDNA) network called kinetoplast DNA (kDNA). Replication of kDNA occurs once per cell cycle in near synchrony with nuclear S phase and requires the coordination of many proteins. Among these are three essential DNA polymerases (TbPOLIB, IC, and ID). Localization dynamics of these proteins with respect to kDNA replication stages and how they coordinate their functions during replication are not well understood. We previously demonstrated that TbPOLID undergoes dynamic localization changes that are coupled to kDNA replication events. Here, we report the localization of TbPOLIC, a second essential DNA polymerase, and demonstrate the accumulation of TbPOLIC foci at active kDNA replication sites (antipodal sites) during stage II of the kDNA duplication cycle. While TbPOLIC was undetectable by immunofluorescence during other cell cycle stages, steady-state protein levels measured by Western blot remained constant. TbPOLIC foci colocalized with the fraction of TbPOLID that localized to the antipodal sites. However, the partial colocalization of the two essential DNA polymerases suggests a highly dynamic environment at the antipodal sites to coordinate the trafficking of replication proteins during kDNA synthesis. These data indicate that cell cycle-dependent localization is a major regulatory mechanism for essential mtDNA polymerases during kDNA replication.</p>
},
	keywords = {Cell Cycle, DNA Replication, DNA, Kinetoplast, DNA-Directed DNA Polymerase, Gene Knockdown Techniques, Gene Silencing, Mitochondria, Protozoan Proteins, S Phase, Trypanosoma brucei brucei},
	issn = {1939-4586},
	doi = {10.1091/mbc.E18-02-0127},
	author = {Concepci{\'o}n-Acevedo, Jeniffer and Miller, Jonathan C and Boucher, Michael J and Klingbeil, Michele M}
}
@article {1274,
	title = {Trypanosoma brucei Orc1 is essential for nuclear DNA replication and affects both VSG silencing and VSG switching.},
	journal = {Mol Microbiol},
	volume = {87},
	year = {2013},
	month = {2013 Jan},
	pages = {196-210},
	abstract = {<p>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\&$\#$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.\&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.\&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.</p>
},
	keywords = {Antigenic Variation, DNA Replication, DNA, Protozoan, Gene Silencing, Genes, Protozoan, Membrane Glycoproteins, Origin Recognition Complex, Promoter Regions, Genetic, Trypanosoma brucei brucei, Variant Surface Glycoproteins, Trypanosoma},
	issn = {1365-2958},
	doi = {10.1111/mmi.12093},
	author = {Benmerzouga, Imaan and Concepci{\'o}n-Acevedo, Jeniffer and Kim, Hee-Sook and Vandoros, Anthula V and Cross, George A M and Klingbeil, Michele M and Li, Bibo}
}
@article {382,
	title = {Mitochondrial DNA polymerase POLIB is essential for minicircle DNA replication in African trypanosomes.},
	journal = {Mol Microbiol},
	volume = {75},
	year = {2010},
	month = {2010 Mar},
	pages = {1414-25},
	abstract = {The unique mitochondrial DNA of trypanosomes is a catenated network of minicircles and maxicircles called kinetoplast DNA (kDNA). The network is essential for survival, and requires an elaborate topoisomerase-mediated release and reattachment mechanism for minicircle theta structure replication. At least seven DNA polymerases (pols) are involved in kDNA transactions, including three essential proteins related to bacterial DNA pol I (POLIB, POLIC and POLID). How Trypanosoma brucei utilizes multiple DNA pols to complete the topologically complex task of kDNA replication is unknown. To fill this gap in knowledge we investigated the cellular role of POLIB using RNA interference (RNAi). POLIB silencing resulted in growth inhibition and progressive loss of kDNA networks. Additionally, unreplicated covalently closed precursors become the most abundant minicircle replication intermediate as minicircle copy number declines. Leading and lagging strand minicircle progeny similarly declined during POLIB silencing, indicating POLIB had no apparent strand preference. Interestingly, POLIB RNAi led to the accumulation of a novel population of free minicircles that is composed mainly of covalently closed minicircle dimers. Based on these data, we propose that POLIB performs an essential role at the core of the minicircle replication machinery.},
	keywords = {DNA Polymerase beta, DNA Replication, DNA, Kinetoplast, Gene Silencing, Protozoan Proteins, Trypanosoma brucei brucei},
	issn = {1365-2958},
	doi = {10.1111/j.1365-2958.2010.07061.x},
	author = {Bruhn, David F and Mozeleski, Brian and Falkin, Laurie and Klingbeil, Michele M}
}
