TbKAP6, a mitochondrial HMG box-containing protein in Trypanosoma brucei, Is the first trypanosomatid kinetoplast- associated protein essential for kinetoplast DNA replication and maintenance

Jianyang Wang, Valeria Pappas-Brown, Paul T. Englund, Robert E. Jensen

Research output: Contribution to journalArticle

Abstract

Kinetoplast DNA (kDNA), the mitochondrial genome of trypanosomatids, is a giant planar network of catenated minicircles and maxicircles. In vivo kDNA is organized as a highly condensed nucleoprotein disk. So far, in Trypanosoma brucei, proteins involved in the maintenance of the kDNA condensed structure remain poorly characterized. In Crithidia fasciculata, some small basic histone H1-like kinetoplast-associated proteins (CfKAP) have been shown to condense isolated kDNA networks in vitro. High-mobility group (HMG) box-containing proteins, such as mitochondrial transcription factor A (TFAM) in mammalian cells and Abf2 in the budding yeast, have been shown essential for the packaging of mitochondrial DNA (mtDNA) into mitochondrial nucleoids, remodeling of mitochondrial nucleoids, gene expression, and maintenance of mtDNA. Here, we report that TbKAP6, a mitochondrial HMG box-containing protein, is essential for parasite cell viability and involved in kDNA replication and maintenance. The RNA interference (RNAi) depletion of TbKAP6 stopped cell growth. Replication of both minicircles and maxicircles was inhibited. RNAi or overexpression of TbKAP6 resulted in the disorganization, shrinkage, and loss of kDNA. Minicircle release, the first step in kDNA replication, was inhibited immediately after induction of RNAi, but it quickly increased 3-fold upon overexpression of TbKAP6. Since the release of covalently closed minicircles is mediated by a type II topoisomerase (topo II), we examined the potential interactions between TbKAP6 and topo II. Recombinant TbKAP6 (rTbKAP6) promotes the topo II-mediated decatenation of kDNA. rTbKAP6 can condense isolated kDNA networks in vitro. These results indicate that TbKAP6 is involved in the replication and maintenance of kDNA.

Original languageEnglish (US)
Pages (from-to)919-932
Number of pages14
JournalEukaryotic Cell
Volume13
Issue number7
DOIs
StatePublished - 2014

Fingerprint

HMGB Proteins
Kinetoplast DNA
Trypanosoma brucei brucei
DNA Replication
Maintenance
Proteins
RNA Interference
Mitochondrial DNA
Crithidia fasciculata
Type II DNA Topoisomerase
Saccharomycetales
Nucleoproteins
Mitochondrial Genome
Mitochondrial Genes
Product Packaging
Histones
Cell Survival
Parasites

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this

TbKAP6, a mitochondrial HMG box-containing protein in Trypanosoma brucei, Is the first trypanosomatid kinetoplast- associated protein essential for kinetoplast DNA replication and maintenance. / Wang, Jianyang; Pappas-Brown, Valeria; Englund, Paul T.; Jensen, Robert E.

In: Eukaryotic Cell, Vol. 13, No. 7, 2014, p. 919-932.

Research output: Contribution to journalArticle

@article{75357e5d9efa4657b5af57ec6060fe5c,
title = "TbKAP6, a mitochondrial HMG box-containing protein in Trypanosoma brucei, Is the first trypanosomatid kinetoplast- associated protein essential for kinetoplast DNA replication and maintenance",
abstract = "Kinetoplast DNA (kDNA), the mitochondrial genome of trypanosomatids, is a giant planar network of catenated minicircles and maxicircles. In vivo kDNA is organized as a highly condensed nucleoprotein disk. So far, in Trypanosoma brucei, proteins involved in the maintenance of the kDNA condensed structure remain poorly characterized. In Crithidia fasciculata, some small basic histone H1-like kinetoplast-associated proteins (CfKAP) have been shown to condense isolated kDNA networks in vitro. High-mobility group (HMG) box-containing proteins, such as mitochondrial transcription factor A (TFAM) in mammalian cells and Abf2 in the budding yeast, have been shown essential for the packaging of mitochondrial DNA (mtDNA) into mitochondrial nucleoids, remodeling of mitochondrial nucleoids, gene expression, and maintenance of mtDNA. Here, we report that TbKAP6, a mitochondrial HMG box-containing protein, is essential for parasite cell viability and involved in kDNA replication and maintenance. The RNA interference (RNAi) depletion of TbKAP6 stopped cell growth. Replication of both minicircles and maxicircles was inhibited. RNAi or overexpression of TbKAP6 resulted in the disorganization, shrinkage, and loss of kDNA. Minicircle release, the first step in kDNA replication, was inhibited immediately after induction of RNAi, but it quickly increased 3-fold upon overexpression of TbKAP6. Since the release of covalently closed minicircles is mediated by a type II topoisomerase (topo II), we examined the potential interactions between TbKAP6 and topo II. Recombinant TbKAP6 (rTbKAP6) promotes the topo II-mediated decatenation of kDNA. rTbKAP6 can condense isolated kDNA networks in vitro. These results indicate that TbKAP6 is involved in the replication and maintenance of kDNA.",
author = "Jianyang Wang and Valeria Pappas-Brown and Englund, {Paul T.} and Jensen, {Robert E.}",
year = "2014",
doi = "10.1128/EC.00260-13",
language = "English (US)",
volume = "13",
pages = "919--932",
journal = "Eukaryotic Cell",
issn = "1535-9778",
publisher = "American Society for Microbiology",
number = "7",

}

TY - JOUR

T1 - TbKAP6, a mitochondrial HMG box-containing protein in Trypanosoma brucei, Is the first trypanosomatid kinetoplast- associated protein essential for kinetoplast DNA replication and maintenance

AU - Wang, Jianyang

AU - Pappas-Brown, Valeria

AU - Englund, Paul T.

AU - Jensen, Robert E.

PY - 2014

Y1 - 2014

N2 - Kinetoplast DNA (kDNA), the mitochondrial genome of trypanosomatids, is a giant planar network of catenated minicircles and maxicircles. In vivo kDNA is organized as a highly condensed nucleoprotein disk. So far, in Trypanosoma brucei, proteins involved in the maintenance of the kDNA condensed structure remain poorly characterized. In Crithidia fasciculata, some small basic histone H1-like kinetoplast-associated proteins (CfKAP) have been shown to condense isolated kDNA networks in vitro. High-mobility group (HMG) box-containing proteins, such as mitochondrial transcription factor A (TFAM) in mammalian cells and Abf2 in the budding yeast, have been shown essential for the packaging of mitochondrial DNA (mtDNA) into mitochondrial nucleoids, remodeling of mitochondrial nucleoids, gene expression, and maintenance of mtDNA. Here, we report that TbKAP6, a mitochondrial HMG box-containing protein, is essential for parasite cell viability and involved in kDNA replication and maintenance. The RNA interference (RNAi) depletion of TbKAP6 stopped cell growth. Replication of both minicircles and maxicircles was inhibited. RNAi or overexpression of TbKAP6 resulted in the disorganization, shrinkage, and loss of kDNA. Minicircle release, the first step in kDNA replication, was inhibited immediately after induction of RNAi, but it quickly increased 3-fold upon overexpression of TbKAP6. Since the release of covalently closed minicircles is mediated by a type II topoisomerase (topo II), we examined the potential interactions between TbKAP6 and topo II. Recombinant TbKAP6 (rTbKAP6) promotes the topo II-mediated decatenation of kDNA. rTbKAP6 can condense isolated kDNA networks in vitro. These results indicate that TbKAP6 is involved in the replication and maintenance of kDNA.

AB - Kinetoplast DNA (kDNA), the mitochondrial genome of trypanosomatids, is a giant planar network of catenated minicircles and maxicircles. In vivo kDNA is organized as a highly condensed nucleoprotein disk. So far, in Trypanosoma brucei, proteins involved in the maintenance of the kDNA condensed structure remain poorly characterized. In Crithidia fasciculata, some small basic histone H1-like kinetoplast-associated proteins (CfKAP) have been shown to condense isolated kDNA networks in vitro. High-mobility group (HMG) box-containing proteins, such as mitochondrial transcription factor A (TFAM) in mammalian cells and Abf2 in the budding yeast, have been shown essential for the packaging of mitochondrial DNA (mtDNA) into mitochondrial nucleoids, remodeling of mitochondrial nucleoids, gene expression, and maintenance of mtDNA. Here, we report that TbKAP6, a mitochondrial HMG box-containing protein, is essential for parasite cell viability and involved in kDNA replication and maintenance. The RNA interference (RNAi) depletion of TbKAP6 stopped cell growth. Replication of both minicircles and maxicircles was inhibited. RNAi or overexpression of TbKAP6 resulted in the disorganization, shrinkage, and loss of kDNA. Minicircle release, the first step in kDNA replication, was inhibited immediately after induction of RNAi, but it quickly increased 3-fold upon overexpression of TbKAP6. Since the release of covalently closed minicircles is mediated by a type II topoisomerase (topo II), we examined the potential interactions between TbKAP6 and topo II. Recombinant TbKAP6 (rTbKAP6) promotes the topo II-mediated decatenation of kDNA. rTbKAP6 can condense isolated kDNA networks in vitro. These results indicate that TbKAP6 is involved in the replication and maintenance of kDNA.

UR - http://www.scopus.com/inward/record.url?scp=84903631577&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84903631577&partnerID=8YFLogxK

U2 - 10.1128/EC.00260-13

DO - 10.1128/EC.00260-13

M3 - Article

C2 - 24879122

AN - SCOPUS:84903631577

VL - 13

SP - 919

EP - 932

JO - Eukaryotic Cell

JF - Eukaryotic Cell

SN - 1535-9778

IS - 7

ER -