p166, a link between the trypanosome mitochondrial DNA and flagellum, mediates genome segregation

EMBO J. 2008 Jan 9;27(1):143-54. doi: 10.1038/sj.emboj.7601956. Epub 2007 Dec 6.


Kinetoplast DNA (kDNA), the trypanosome mitochondrial genome, is a giant network containing several thousand interlocked DNA rings. Within the mitochondrion, kDNA is condensed into a disk-shaped structure positioned near the flagellar basal body. The disk is linked to the basal body by a remarkable transmembrane filament system named the tripartite attachment complex (TAC). Following kDNA replication, the TAC mediates network segregation, pulling the progeny networks into the daughter cells by their linkage to the basal bodies. So far TAC has been characterized only morphologically with no known protein components. By screening an RNAi library, we discovered p166, a protein localizing between the kDNA and basal body in intact cells and in isolated flagellum-kDNA complexes. RNAi of p166 has only small effects on kDNA replication, but it causes profound defects in network segregation. For example, kDNA replication without segregation causes the networks to grow to enormous size. Thus, p166 is the first reported molecular component of the TAC, and its discovery will facilitate study of kDNA segregation machinery at the molecular level.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • DNA, Kinetoplast / physiology*
  • Flagella / genetics
  • Flagella / physiology*
  • Genome, Mitochondrial*
  • Genome, Protozoan*
  • Mitochondrial Membranes / chemistry
  • Mitochondrial Membranes / physiology
  • Mitochondrial Proteins / antagonists & inhibitors
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / physiology*
  • Protozoan Proteins / antagonists & inhibitors
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics
  • Protozoan Proteins / physiology*
  • RNA Interference
  • Trypanosoma brucei brucei / chemistry
  • Trypanosoma brucei brucei / genetics
  • Trypanosoma brucei brucei / physiology*


  • DNA, Kinetoplast
  • Mitochondrial Proteins
  • Protozoan Proteins