Mitochondrial development during life cycle differentiation of African trypanosomes: evidence for a kinetoplast-dependent differentiation control point.
Life cycle differentiation of African trypanosomes entails developmental regulation of mitochondrial activity. This requires regulation of the nuclear genome and the kinetoplast, the trypanosome's unusual mitochondrial genome. To investigate the potential cross talk between the nuclear and mitochondrial genome during the events of differentiation, we have 1) disrupted expression of a nuclear-encoded component of the cytochrome oxidase (COX) complex; and 2) generated dyskinetoplastid cells, which lack a mitochondrial genome. Using RNA interference (RNAi) and by disrupting the nuclear COX VI gene, we demonstrate independent regulation of COX component mRNAs encoded in the nucleus and kinetoplast. However, two independent approaches (acriflavine treatment and RNA interference ablation of mitochondrial topoisomerase II) failed to establish clonal lines of dyskinetoplastid bloodstream forms. Nevertheless, dyskinetoplastid forms generated in vivo could undergo two life cycle differentiation events: transition from bloodstream slender to stumpy forms and the initiation of transformation to procyclic forms. However, they subsequently arrested at a specific point in this developmental program before cell cycle reentry. These results provide strong evidence for a requirement for kinetoplast DNA in the bloodstream and for a kinetoplast-dependent control point during differentiation to procyclic forms.
Timms
Mark W
MW
School of Biological Sciences, University of Manchester, Manchester, M13 9PT United Kingdom.
van Deursen
Frederick J
FJ
Hendriks
Edward F
EF
Matthews
Keith R
KR
D000167:Acriflavine / Q000494:pharmacology; D000349:Africa; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D000963:Antimetabolites / Q000494:pharmacology; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism; D018105:DNA, Kinetoplast; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D018390:Gene Targeting; D018503:Genome, Protozoan; D008018:Life Cycle Stages / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics* / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D014345:Trypanosoma / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D000891:Anti-Infective Agents, Local; D000963:Antimetabolites; D018105:DNA, Kinetoplast; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; C053277:procyclic acidic repetitive protein, Trypanosoma; D000167:Acriflavine; D012313:RNA; D003576:Electron Transport Complex IV; D004250:DNA Topoisomerases, Type II