scholarly journals TheUNI3Gene Is Required for Assembly of Basal Bodies ofChlamydomonasand Encodes δ-Tubulin, a New Member of the Tubulin Superfamily

1998 ◽  
Vol 9 (6) ◽  
pp. 1293-1308 ◽  
Author(s):  
Susan K. Dutcher ◽  
Emanuel C. Trabuco
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Basal Body ◽  
Pedigree Analysis ◽  
Basal Bodies ◽  
Cleavage Furrow ◽  
Sequence Identity ◽  
Cycle Dependent ◽  
Single Flagellum

We have cloned the UNI3 gene inChlamydomonas and find that it encodes a new member of the tubulin superfamily. Although Uni3p shares significant sequence identity with α-, β-, and γ-tubulins, there is a region of Uni3p that has no similarity to tubulins or other known proteins. Mutantuni3–1 cells assemble zero, one, or two flagella. Pedigree analysis suggests that flagellar number inuni3–1 cells is a function of the age of the cell. The uniflagellate uni3–1 cells show a positional phenotype; the basal body opposite the eyespot templates the single flagellum. A percentage of uni3–1 cells also fail to orient the cleavage furrow properly, and basal bodies have been implicated in the placement of cleavage furrows in Chlamydomonas. Finally when uni3–1 cells are observed by electron microscopy, doublet rather than triplet microtubules are observed at the proximal end of the basal bodies. We propose that the Uni3 tubulin is involved in both the function and cell cycle-dependent maturation of basal bodies/centrioles.

scholarly journals The ultrastructure of cell division in Euglena gracilis

1978 ◽  
Vol 31 (1) ◽  
pp. 25-35
Author(s):  
M.A. Gillott ◽  
R.E. Triemer
Keyword(s):  
Cell Division ◽  
Nuclear Envelope ◽  
Basal Body ◽  
Euglena Gracilis ◽  
Equatorial Region ◽  
Basal Bodies ◽  
Cleavage Furrow ◽  
Free Zone ◽  
Prophase Nucleus

The ultrastructure of mitosis in Euglena gracilis was investigated. At preprophase the nucleus migrates anteriorly and associates with the basal bodies. Flagella and basal bodies replicate at preprophase. Cells retain motility throughout division. The reservoir and the prophase nucleus elongate perpendicular to the incipient cleavage furrow. One basal body pair surrounded by a ribosome-free zone is found at each of the nuclear poles. The spindle forms within the intact nuclear envelope- Polar fenestrae are absent. At metaphase, the endosome is elongated from pole to pole, and chromosomes are loosely arranged in the equatorial region. Distinct, trilayered kinetochores are present. Spindle elongates as chromosomes migrate to the poles forming a dumb-bell shaped nucleus by telophase. Daughter nuclei are formed by constriction of the nuclear envelope. Cytokinesis is accomplished by furrowing. Cell division in Euglena is compared with that of certain other algae.

The cell division cycle of Trypanosoma brucei brucei : timing of event markers and cytoskeletal modulations

1989 ◽  
Vol 323 (1218) ◽  
pp. 573-588 ◽  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Trypanosoma Brucei ◽  
Basal Body ◽  
Single Copy ◽  
Cell Division Cycle ◽  
Basal Bodies ◽  
Division Plane ◽  
Transmission Electron ◽  
Single Nucleus

We have analysed the timing and order of events occurring within the cell division cycle of Trypanosoma brucei . Cells in the earliest stages of the cell cycle possess a single copy of three major organelles: the nucleus, the kinetoplast and the flagellum. The first indication of progress through the cell cycle is the elongation of the pro-basal body lying adjacent to the mature basal body subtending the flagellum. This newly elongated basal body occupies a posterior position within the cell when it initiates growth of the new daughter flagellum. Genesis of two new pro-basal bodies occurs only after growth of the new daughter flagellum has been initiated. Extension of the new flagellum, together with the paraflagellar rod, then continues throughout a major portion of the cell cycle. During this period of flagellum elongation, kinetoplast division occurs and the two kinetoplasts, together with the two flagellar basal bodies, then move apart within the cell. Mitosis is then initiated and a complex pattern of organelle positions is achieved whereby a division plane runs longitudinally through the cell such that each daughter ultimately receives a single nucleus, kinetoplast and flagellum. These events have been described from observations of whole cytoskeletons by transmission electron microscopy together with detection of particular organelles by fluorescence microscopy. The order and timing of events within the cell cycle has been derived from analyses of the proportion of a given cell type occurring within an exponentially growing culture.

scholarly journals Patterns of basal body addition in ciliary rows in Tetrahymena.

1975 ◽  
Vol 65 (3) ◽  
pp. 503-512 ◽  
Author(s):  
D L Nanney
Keyword(s):  
Cell Cycle ◽  
Basal Body ◽  
High Frequency ◽  
Rapid Development ◽  
Basal Bodies ◽  
Full Cell ◽  
Daughter Cells ◽  
Ciliary Shaft

Most naked basal bodies visualized in protargol stains on the surface of Tetrahymena are new basal bodies which have not yet developed cilia. The rarity of short cilia is explained by the rapid development of the ciliary shaft once it begins to grow. The high frequency of naked basal bodies (about 50 percent) in log cultures indicates that the interval between assembly of the basal body and the initiation of the cilium is long, approximately a full cell cycle. Naked basal bodies are more frequent in the mid and posterior parts of the cell and two or more naked basal bodies may be associated with one ciliated basal body in these regions. Daughter cells produced at division are apparently asymmetric with respect to their endowment of new and old organelles.

scholarly journals The basal bodies of Chlamydomonas reinhardtii. Formation from probasal bodies, isolation, and partial characterization.

1975 ◽  
Vol 65 (1) ◽  
pp. 65-74 ◽  
Author(s):  
R R Gould
Keyword(s):  
Electron Microscopy ◽  
Chlamydomonas Reinhardtii ◽  
Basal Body ◽  
Sodium Dodecyl ◽  
Basal Bodies ◽  
Polyethylene Glycol 400 ◽  
Thin Sections ◽  
Particulate Contamination ◽  
Whole Mount ◽  
Carbon Coated

The assembly and composition of basal bodies was investigated in the single-celled, biflagellate green alga, Chlamydomonas reinhardtii, using the cell wall-less strain, cw15. In the presence of EDTA, both flagellar axonemes remained attached to their basal bodies while the entire basal body-axoneme complex was separated from the cell body, without cell lysis, by treatment with polyethylene glycol-400. The axonemes were then removed from the basal bodies in the absence of EDTA, leaving intact basal body pairs, free from particulate contamination from other regions of the cell. The isolated organelles produced several bands on sodium dodecyl sulfate-urea polyacrylamide gels, including two tubilin bands which co-electrophoresed with flagellar tubulin. The formation of probasal bodies was observed by electron microscopy of whole mount preparations. Synchronous cells were lysed, centrifuged onto carbon-coated grids, and either negatively stained or shadowed with platinum. The two probasal bodies of each cell appeared shortly after mitosis as thin "annuli," not visible in thin sections, each consisting of nine rudimentary triplet microtubules. Each annulus remained attached to one of the mature basal bodies by several filaments about 60 in diameter, and persisted throughout interphase until just before the next cell division. It then elongated into a mature organelle. The results revive the possibility of the nucleated assembly of basal bodies.

Identification of a Cell Cycle-Dependent Duplicating Complex that Assembles Basal Bodies de novo in Naegleria

Protist ◽  
2015 ◽  
Vol 166 (1) ◽  
pp. 1-13 ◽  
Author(s):  
JungHa Lee ◽  
Seungmin Kang ◽  
Yong Seok Choi ◽  
Hong-Kyung Kim ◽  
Chang-Yeol Yeo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
De Novo ◽  
Basal Bodies ◽  
A Cell ◽  
Cycle Dependent

scholarly journals The Uni2 Phosphoprotein is a Cell Cycle–regulated Component of the Basal Body Maturation Pathway in Chlamydomonas reinhardtii

2008 ◽  
Vol 19 (1) ◽  
pp. 262-273 ◽  
Author(s):  
Brian P. Piasecki ◽  
Matthew LaVoie ◽  
Lai-Wa Tam ◽  
Paul A. Lefebvre ◽  
Carolyn D. Silflow
Keyword(s):  
Cell Cycle ◽  
Chlamydomonas Reinhardtii ◽  
Basal Body ◽  
Basal Bodies ◽  
Mitotic Progression ◽  
Transition Zones ◽  
Phosphatase Treatment ◽  
Flagellar Assembly ◽  
A Cell ◽  
Sequential Assembly

Mutations in the UNI2 locus in Chlamydomonas reinhardtii result in a “uniflagellar” phenotype in which flagellar assembly occurs preferentially from the older basal body and ultrastructural defects reside in the transition zones. The UNI2 gene encodes a protein of 134 kDa that shares 20.5% homology with a human protein. Immunofluorescence microscopy localized the protein on both basal bodies and probasal bodies. The protein is present as at least two molecular-weight variants that can be converted to a single form with phosphatase treatment. Synthesis of Uni2 protein is induced during cell division cycles; accumulation of the phosphorylated form coincides with assembly of transition zones and flagella at the end of the division cycle. Using the Uni2 protein as a cell cycle marker of basal bodies, we observed migration of basal bodies before flagellar resorption in some cells, indicating that flagellar resorption is not required for mitotic progression. We observed the sequential assembly of new probasal bodies beginning at prophase. The uni2 mutants may be defective in the pathways leading to flagellar assembly and to basal body maturation.

scholarly journals THE SYNTHESIS OF MICROTUBULE AND OTHER PROTEINS OF THE ORAL APPARATUS IN TETRAHYMENA PYRIFORMIS

1971 ◽  
Vol 50 (3) ◽  
pp. 709-720 ◽  
Author(s):  
John Rannestad ◽  
Norman E. Williams
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Acetic Acid ◽  
Tetrahymena Pyriformis ◽  
Basal Bodies

Several proteins, including microtubule proteins, have been isolated from the oral apparatus of the ciliate Tetrahymena. The synthesis of these proteins has been studied in relation to formation of this organelle system by the cell. Electron microscopy has shown that the isolated oral apparatus consists primarily of basal bodies, pellicular membranes, and a system of subpellicular microtubules and filaments. Cilia were removed during the isolation; therefore none of the proteins studied was from these structures. Evidence was obtained from the study of total oral apparatus protein which indicates that at least some of the proteins involved in formation of this organelle system may be synthesized and stored in the cytoplasm for use over long periods. This pattern of regulation was found for three individual proteins isolated from the oral apparatus fraction after extraction with a phenol-acetic acid solvent. A different pattern of regulation was found for microtubule proteins isolated from the oral apparatus of Tetrahymena. The data suggest that microtubule proteins, at least in logarithmically growing cells, are not stored in a cytoplasmic pool but are synthesized in the same cell cycle in which they are assembled into oral structures.

scholarly journals An analogue-sensitive approach identifies basal body rotation and flagellum attachment zone elongation as key functions of PLK in Trypanosoma brucei

2013 ◽  
Vol 24 (9) ◽  
pp. 1321-1333 ◽  
Author(s):  
Ana Lozano-Núñez ◽  
Kyojiro N. Ikeda ◽  
Thomas Sauer ◽  
Christopher L. de Graffenried
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Rna Interference ◽  
Cell Surface ◽  
Trypanosoma Brucei ◽  
Basal Body ◽  
Basal Bodies ◽  
Body Rotation ◽  
The Many ◽  
Attachment Zone

Polo-like kinases are important regulators of cell division, playing diverse roles in mitosis and cytoskeletal inheritance. In the parasite Trypanosoma brucei, the single PLK homologue TbPLK is necessary for the assembly of a series of essential organelles that position and adhere the flagellum to the cell surface. Previous work relied on RNA interference or inhibitors of undefined specificity to inhibit TbPLK, both of which have significant experimental limitations. Here we use an analogue-sensitive approach to selectively and acutely inhibit TbPLK. T. brucei cells expressing only analogue-sensitive TbPLK (TbPLKas) grow normally, but upon treatment with inhibitor develop defects in flagellar attachment and cytokinesis. TbPLK cannot migrate effectively when inhibited and remains trapped in the posterior of the cell throughout the cell cycle. Using synchronized cells, we show that active TbPLK is a direct requirement for the assembly and extension of the flagellum attachment zone, which adheres the flagellum to the cell surface, and for the rotation of the duplicated basal bodies, which positions the new flagellum so that it can extend without impinging on the old flagellum. This approach should be applicable to the many kinases found in the T. brucei genome that lack an ascribed function.

scholarly journals ε-Tubulin Is an Essential Component of the Centriole

2002 ◽  
Vol 13 (11) ◽  
pp. 3859-3869 ◽  
Author(s):  
Susan K. Dutcher ◽  
Naomi S. Morrissette ◽  
Andrea M. Preble ◽  
Craig Rackley ◽  
John Stanga
Keyword(s):  
Basal Body ◽  
Positional Cloning ◽  
Stop Codon ◽  
Polyclonal Antibodies ◽  
Premature Stop Codon ◽  
Full Length ◽  
Basal Bodies ◽  
Cleavage Furrow ◽  
Essential Component ◽  
Flagellar Assembly

Centrioles and basal bodies are cylinders composed of nine triplet microtubule blades that play essential roles in the centrosome and in flagellar assembly. Chlamydomonas cells with thebld2-1 mutation fail to assemble doublet and triplet microtubules and have defects in cleavage furrow placement and meiosis. Using positional cloning, we have walked 720 kb and identified a 13.2-kb fragment that contains ε-tubulin and rescues the Bld2 defects. The bld2-1 allele has a premature stop codon and intragenic revertants replace the stop codon with glutamine, glutamate, or lysine. Polyclonal antibodies to ε-tubulin show peripheral labeling of full-length basal bodies and centrioles. Thus, ε-tubulin is encoded by the BLD2 allele and ε-tubulin plays a role in basal body/centriole morphogenesis.

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