Centriole symmetry: A big tale from small organisms

Riparbelli, Maria Giovanna; Dallai, Romano; Mercati, David; Bu, Yun; Callaini, Giuliano

doi:10.1002/cm.20417

Cited by 22 publications

(13 citation statements)

References 22 publications

(26 reference statements)

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“…S1B) as demonstrated previously (25). This is similar in size to the central tubules of most of the model organisms (supplemental Table 1) with the exception of the hexapod Acerentomon microrhinus, where the diameter of the central tubule varied according to the centriole diameter (27). Analysis of cryo-EM tomograms of centrosomes suggested that the central tubule is an extended structure along the axis of the centriole (supplemental Movies 1 and 2).…”

Section: Sas-6 Is a Component Of The Centriole Central Tubule-tosupporting

confidence: 81%

Self-assembling SAS-6 Multimer Is a Core Centriole Building Block

Gopalakrishnan

Guichard

Smith

et al. 2010

Journal of Biological Chemistry

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Centrioles are conserved microtubule-based organelles with 9-fold symmetry that are essential for cilia and mitotic spindle formation. A conserved structure at the onset of centriole assembly is a "cartwheel" with 9-fold radial symmetry and a central tubule in its core. It remains unclear how the cartwheel is formed. The conserved centriole protein, SAS-6, is a cartwheel component that functions early in centriole formation. Here, combining biochemistry and electron microscopy, we characterize SAS-6 and show that it self-assembles into stable tetramers, which serve as building blocks for the central tubule. These results suggest that SAS-6 selfassembly may be an initial step in the formation of the cartwheel that provides the 9-fold symmetry. Electron microscopy of centrosomes identified 25-nm central tubules with repeating subunits and show that SAS-6 concentrates at the core of the cartwheel. Recombinant and native SAS-6 selfoligomerizes into tetramers with ϳ6-nm subunits, and these tetramers are components of the centrosome, suggesting that tetramers are the building blocks of the central tubule. This is further supported by the observation that elevated levels of SAS-6 in Drosophila cells resulted in higher order structures resembling central tubule morphology. Finally, in the presence of embryonic extract, SAS-6 tetramers assembled into high density complexes, providing a starting point for the eventual in vitro reconstruction of centrioles.

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Section: Sas-6 Is a Component Of The Centriole Central Tubule-tosupporting

confidence: 81%

Self-assembling SAS-6 Multimer Is a Core Centriole Building Block

Gopalakrishnan

Guichard

Smith

et al. 2010

Journal of Biological Chemistry

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“…The axoneme is the structural backbone of the cilium and mirrors the nine-fold radial symmetry conveyed by the basal body (Riparbelli et al, 2009b). Generally, motile cilia contain a pair of axial singlet microtubules at the center of the axoneme surrounded by the nine doublet microtubules of the axoneme: a “9+2” structure.…”

Section: Introductionmentioning

confidence: 99%

Assembly and Persistence of Primary Cilia in Dividing Drosophila Spermatocytes

2012

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Basal bodies are freed from cilia and transition into centrioles to organize centrosomes in dividing cells. A mutually exclusive centriole/basal body existence during cell cycle progression has become a widely accepted principle. Contrary to this view, we show here that cilia assemble and persist through two meiotic divisions in Drosophila spermatocytes. Remarkably, all four centrioles assemble primary cilia-centriole complexes that transit from the plasma membrane encased in a packet of membrane, recruit centrosomal material into microtubule-organizing centers, and persist at the spindle poles through division. Thus, spermatocyte centrioles organize centrosomes and cilia simultaneously at cell division. These findings challenge the prevailing view that cilia antagonize cell cycle progression, and raise the possibility that cilium retention at cell division may occur in diverse organisms and cell types.

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“…One mechanism that generates or maintains asymmetry is the regulated trafficking of specific cellular components (Sann et al, 2009;Peters and Kropf, 2010;Poulain and Sobel, 2010). The microtubule cytoskeleton is a key player in intracellular transport and is itself inherently asymmetric as a result of age differences between the two cen trosomes/basal bodies that nucleate the microtubules (Piel et al, 2000;Dutcher, 2003;Anderson and Stearns, 2009;Riparbelli et al, 2009;Wang et al, 2009;Yamashita, 2009) and the inher ent directionality of the tubulin polymer (Li and Gundersen, 2008;Coquelle et al, 2009).…”

Section: Introductionmentioning

confidence: 99%