Architecture of the Trypanosoma brucei nucleus during interphase and mitosis

Ogbadoyi, Emmanuel O.; Ersfeld, Klaus; Robinson, Derrick R.; Sherwin, Trevor; Gull, Keith

doi:10.1007/s004120050402

Cited by 129 publications

(186 citation statements)

References 54 publications

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“…4,38,[79][80][81] Thus, in conjunction with divergent lamin-like proteins, 35,82 and unconventional kinetochores, 83 it seems that the trypanosome nucleus uses unique protein complexes in parallel with conserved core elements such as the spindle microtubules and outer kinetochore components, Ndc80/Nuf2 to facilitate trypanosome biology. 84,85 Did trypanosomes retain an ancient symmetric assembly or reconfigure their molecular biology through the loss of introns and individual gene promoters (Fig. 2) and thereby dispense with the need to utilize ATP as an energy source for separately powering mRNA export?…”

Section: Tms and Alps: Multiple Ways To Tether A Leviathanmentioning

confidence: 99%

Comparative interactomics provides evidence for functional specialization of the nuclear pore complex

Obado

Field

Rout

2017

Nucleus

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The core architecture of the eukaryotic cell was established well over one billion years ago, and is largely retained in all extant lineages. However, eukaryotic cells also possess lineagespecific features, frequently keyed to specific functional requirements. One quintessential core eukaryotic structure is the nuclear pore complex (NPC), responsible for regulating exchange of macromolecules between the nucleus and cytoplasm as well as acting as a nuclear organizational hub. NPC architecture has been best documented in one eukaryotic supergroup, the Opisthokonts (e.g. Saccharomyces cerevisiae and Homo sapiens), which although compositionally similar, have significant variations in certain NPC subcomplex structures. The variation of NPC structure across other taxa in the eukaryotic kingdom however, remains poorly understood. We explored trypanosomes, highly divergent organisms, and mapped and assigned their NPC proteins to specific substructures to reveal their NPC architecture. We showed that the NPC central structural scaffold is conserved, likely across all eukaryotes, but more peripheral elements can exhibit very significant lineage-specific losses, duplications or other alterations in their components. Amazingly, trypanosomes lack the major components of the mRNA export platform that are asymmetrically localized within yeast and vertebrate NPCs. Concomitant with this, the trypanosome NPC is ALMOST completely symmetric with the nuclear basket being the only major source of asymmetry. We suggest these features point toward a stepwise evolution of the NPC in which a coating scaffold first stabilized the pore after which selective gating emerged and expanded, leading to the addition of peripheral remodeling machineries on the nucleoplasmic and cytoplasmic sides of the pore.

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Section: Tms and Alps: Multiple Ways To Tether A Leviathanmentioning

confidence: 99%

Comparative interactomics provides evidence for functional specialization of the nuclear pore complex

Obado

Field

Rout

2017

Nucleus

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“…L. mexicana promastigotes assumed an oval morphology following exposure to hydroxyurea rather than the elongated shape of untreated promastigotes, but LmxKH was nonetheless apparent on the mitotic spindle that separates dividing nuclei. (61) and displayed the rhomboid spindle that converges at two poles at opposite ends of dividing nuclei (62). All preparations were stained with DAPI that detects both nuclear and kinetoplast DNA (blue).…”

Section: Identification Of Tbkh and Subcellular Localization In Bfmentioning

confidence: 99%

KHARON Is an Essential Cytoskeletal Protein Involved in the Trafficking of Flagellar Membrane Proteins and Cell Division in African Trypanosomes

Sánchez

Tran

Valli

et al. 2016

Journal of Biological Chemistry

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African trypanosomes and related kinetoplastid parasites selectively traffic specific membrane proteins to the flagellar membrane, but the mechanisms for this trafficking are poorly understood. We show here that KHARON, a protein originally identified in Leishmania parasites, interacts with a putative trypanosome calcium channel and is required for its targeting to the flagellar membrane. KHARON is located at the base of the flagellar axoneme, where it likely mediates targeting of flagellar membrane proteins, but is also on the subpellicular microtubules and the mitotic spindle. Hence, KHARON is probably a multifunctional protein that associates with several components of the trypanosome cytoskeleton. RNA interference-mediated knockdown of KHARON mRNA results in failure of the calcium channel to enter the flagellar membrane, detachment of the flagellum from the cell body, and disruption of mitotic spindles. Furthermore, knockdown of KHARON mRNA induces a lethal failure of cytokinesis in both bloodstream (mammalian host) and procyclic (insect vector) life cycle stages, and KHARON is thus critical for parasite viability.

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“…DNA probes for the 177-bp minichromosome repeat and the telomere repeat oligonucleotide was labelled with digoxigenin as described [10,14]. The 177 bp repeat-specific probe was hybridised in EasyHyb -buffer (Roche Diagnostics) at 40°C overnight and the final washes were carried out in 15 mM NaCl, 1.5 mM sodium citrate (0.1× SSC)/0.1% (w/v) SDS at 60°C.…”

Section: Southern Blot Analysismentioning

confidence: 99%

Diversity and dynamics of the minichromosomal karyotype in Trypanosoma brucei

Alsford

Wickstead

Ersfeld

et al. 2001

Molecular and Biochemical Parasitology

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The genome of African trypanosomes contains a large number of minichromosomes. Their only proposed role is in the expansion of the parasites' repertoire of telomeric variant surface glycoprotein (VSG) genes as minichromosomes carry silent VSG gene copies in telomeric locations. Despite their importance as VSG gene donors, little is known about the actual composition of the minichromosomal karyotype and the stability of its inheritance. In this study we show, by using high-resolution pulsed-field electrophoresis, that a non-clonal trypanosome population contains an extremely diverse pattern of minichromosomes, which can be resolved into less complex clone-specific karyotypes by non-selective cloning. We show that the minichromosome patterns of such clones are stable over at least 360 generations. Furthermore, using DNA markers for specific minichromosomes, we demonstrate the mitotic stability of these minichromosomes within the population over a period of more than 5 years. Length variation is observed for an individual minichromosome and is most likely caused by a continuous telomeric growth of approximately 6 bp per telomere per cell division. This steady telomeric growth, counteracted by stochastic large losses of telomeric sequences is the most likely cause of minichromosome karyotype heterogeneity within a population.

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Architecture of the Trypanosoma brucei nucleus during interphase and mitosis

Cited by 129 publications

References 54 publications

Comparative interactomics provides evidence for functional specialization of the nuclear pore complex

Comparative interactomics provides evidence for functional specialization of the nuclear pore complex

KHARON Is an Essential Cytoskeletal Protein Involved in the Trafficking of Flagellar Membrane Proteins and Cell Division in African Trypanosomes

Diversity and dynamics of the minichromosomal karyotype in Trypanosoma brucei

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