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TbPIF1, a Trypanosoma brucei mitochondrial DNA helicase, is essential for kinetoplast minicircle replication

Journal Article


Abstract


  • Kinetoplast DNA, the trypanosome mitochondrial genome, is a network of interlocked DNA rings including several thousand minicircles and a few dozen maxicircles. Minicircles replicate after release from the network, and their progeny reattach. Remarkably, trypanosomes have six mitochondrial DNA helicases related to yeast PIF1 helicase. Here we report that one of the six, TbPIF1, functions in minicircle replication. RNA interference (RNAi) of TbPIF1 causes a growth defect and kinetoplast DNA loss. Minicircle replication intermediates decrease during RNAi, and there is an accumulation of multiply interlocked, covalently closed minicircle dimers (fraction U). In studying the significance of fraction U, we found that this species also accumulates during RNAi of mitochondrial topoisomerase II. These data indicate that one function of TbPIF1 is an involvement, together with topoisomerase II, in the segregation of minicircle progeny. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Publication Date


  • 2010

Citation


  • Liu, B., Yildirir, G., Wang, J., Tolun, G., Griffith, J. D., & Englund, P. T. (2010). TbPIF1, a Trypanosoma brucei mitochondrial DNA helicase, is essential for kinetoplast minicircle replication. Journal of Biological Chemistry, 285(10), 7056-7066. doi:10.1074/jbc.M109.084038

Scopus Eid


  • 2-s2.0-77951221949

Start Page


  • 7056

End Page


  • 7066

Volume


  • 285

Issue


  • 10

Abstract


  • Kinetoplast DNA, the trypanosome mitochondrial genome, is a network of interlocked DNA rings including several thousand minicircles and a few dozen maxicircles. Minicircles replicate after release from the network, and their progeny reattach. Remarkably, trypanosomes have six mitochondrial DNA helicases related to yeast PIF1 helicase. Here we report that one of the six, TbPIF1, functions in minicircle replication. RNA interference (RNAi) of TbPIF1 causes a growth defect and kinetoplast DNA loss. Minicircle replication intermediates decrease during RNAi, and there is an accumulation of multiply interlocked, covalently closed minicircle dimers (fraction U). In studying the significance of fraction U, we found that this species also accumulates during RNAi of mitochondrial topoisomerase II. These data indicate that one function of TbPIF1 is an involvement, together with topoisomerase II, in the segregation of minicircle progeny. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Publication Date


  • 2010

Citation


  • Liu, B., Yildirir, G., Wang, J., Tolun, G., Griffith, J. D., & Englund, P. T. (2010). TbPIF1, a Trypanosoma brucei mitochondrial DNA helicase, is essential for kinetoplast minicircle replication. Journal of Biological Chemistry, 285(10), 7056-7066. doi:10.1074/jbc.M109.084038

Scopus Eid


  • 2-s2.0-77951221949

Start Page


  • 7056

End Page


  • 7066

Volume


  • 285

Issue


  • 10