Kinesin 9 family members perform separate functions in the trypanosome flagellum

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Abstract

KIF9B localizes to the axoneme and basal body and is needed for flagella assembly, whereas KIF9A localizes only to the axoneme and controls flagella motility without affecting their structure.

Abstract

Numerous eukaryote genome projects have uncovered a variety of kinesins of unknown function. The kinesin 9 family is limited to flagellated species. Our phylogenetic experiments revealed two subfamilies: KIF9A (including Chlamydomonas reinhardtii KLP1) and KIF9B (including human KIF6). The function of KIF9A and KIF9B was investigated in the protist Trypanosoma brucei that possesses a single motile flagellum. KIF9A and KIF9B are strongly associated with the cytoskeleton and are required for motility. KIF9A is localized exclusively in the axoneme, and its depletion leads to altered motility without visible structural modifications. KIF9B is found in both the axoneme and the basal body, and is essential for the assembly of the paraflagellar rod (PFR), a large extra-axonemal structure. In the absence of KIF9B, cells grow abnormal flagella with excessively large blocks of PFR-like material that alternate with regions where only the axoneme is present. The functional diversity of the kinesin 9 family illustrates the capacity for adaptation of organisms to suit specific cytoskeletal requirements.

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A tightly regulated inducible expression system for conditional gene knock-outs and dominant-negative genetics in Trypanosoma brucei.

E. Wirtz, S. Leal, C Ochatt … (1999)

First-generation inducible expression vectors for Trypanosoma brucei utilized a single tetracycline-responsive promoter to drive expression of an experimental gene, in tandem with a drug-resistance marker gene to select for integration (Wirtz E, Clayton CE. Science 1995; 268:1179-1183). Because drug resistance and experimental gene expression both depended upon the activity of the regulated promoter, this approach could not be used for inducible expression of toxic products. We have now developed a dual-promoter approach, for expressing highly toxic products and generating conditional gene knock-outs, using back-to-back constitutive T7 and tetracycline-responsive PARP promoters to drive expression of the selectable marker and test gene, respectively. Transformants are readily obtained with these vectors in the absence of tetracycline, in bloodstream or procyclic T. brucei cell lines co-expressing T7 RNA polymerase and Tet repressor, and consistently show tetracycline-responsive expression through a 10(3)-10(4)-fold range. Uninduced background expression of a luciferase reporter averages no more than one molecule per cell, enabling dominant-negative approaches relying upon inducible expression of toxic products. This tight regulation also permits the production of functional gene knock-outs through regulated expression of an experimental gene in a null-mutant background.

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TREEFINDER: a powerful graphical analysis environment for molecular phylogenetics

Gangolf Jobb, Arndt von Haeseler, Korbinian Strimmer (2004)

Background Most analysis programs for inferring molecular phylogenies are difficult to use, in particular for researchers with little programming experience. Results TREEFINDER is an easy-to-use integrative platform-independent analysis environment for molecular phylogenetics. In this paper the main features of TREEFINDER (version of April 2004) are described. TREEFINDER is written in ANSI C and Java and implements powerful statistical approaches for inferring gene tree and related analyzes. In addition, it provides a user-friendly graphical interface and a phylogenetic programming language. Conclusions TREEFINDER is a versatile framework for analyzing phylogenetic data across different platforms that is suited both for exploratory as well as advanced studies.

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Analysis of the kinesin superfamily: insights into structure and function.

Harukata Miki, Yasushi Okada, Nobutaka Hirokawa (2005)

Kinesin superfamily proteins (KIFs) are key players or 'hub' proteins in the intracellular transport system, which is essential for cellular function and morphology. The KIF superfamily is also the first large protein family in mammals whose constituents have been completely identified and confirmed both in silico and in vivo. Numerous studies have revealed the structures and functions of individual family members; however, the relationships between members or a perspective of the whole superfamily structure until recently remained elusive. Here, we present a comprehensive summary based on a large, systematic phylogenetic analysis of the kinesin superfamily. All available sequences in public databases, including genomic information from all model organisms, were analyzed to yield the most complete phylogenetic kinesin tree thus far, comprising 14 families. This comprehensive classification builds on the recently proposed standardized nomenclature for kinesins and allows systematic analysis of the structural and functional relationships within the kinesin superfamily.

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Author and article information

Journal

Journal ID (nlm-ta): J Cell Biol

Journal ID (iso-abbrev): J. Cell Biol

Journal ID (hwp): jcb

Title: The Journal of Cell Biology

Publisher: The Rockefeller University Press

ISSN (Print): 0021-9525

ISSN (Electronic): 1540-8140

Publication date (Print): 30 November 2009

Volume: 187

Issue: 5

Pages: 615-622

Affiliations

[1 ]Adaptation Processes of Protozoa to their Environment, Centre National de la Recherche Scientifique FRE3206 and [2 ]Nucleic acids: Dynamics, Targeting and Biological Functions, UMR5153, Muséum National d'Histoire Naturelle, 75231 Paris, France

[3 ]Trypanosome Cell Biology, Centre National de la Recherche Scientifique URA 2581 and [4 ]Plate-forme de Microscopie Ultrastructurale, Institut Pasteur, 75015 Paris, France

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Correspondence to Linda Kohl: lkohl@ 123456mnhn.fr

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Publisher ID: 200903139

DOI: 10.1083/jcb.200903139

PMC ID: 2806587

PubMed ID: 19948486

SO-VID: b2c29234-18e9-4f4b-8b50-4c3dd158b259

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This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

Kinesin 9 family members perform separate functions in the trypanosome flagellum

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Stress signalling in stem cells

Most cited references 33

A tightly regulated inducible expression system for conditional gene knock-outs and dominant-negative genetics in Trypanosoma brucei.

TREEFINDER: a powerful graphical analysis environment for molecular phylogenetics

Analysis of the kinesin superfamily: insights into structure and function.

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