Centriole

Centriole

A mother and daughter centriole, attached orthogonally.
A mother and daughter centriole, attached orthogonally.
Cell biology
The centrosome
Components of a typical centrosome:
  1. Centriole
  2. Mother centriole
  3. Daughter centriole
  4. Distal ends
  5. Distal appendages
  6. Subdistal appendages
  7. Proximal ends
  8. Microtubule triplets
  9. Interconnecting fibers
  10. Microtubules
  11. Pericentriolar material

In cell structure[1] composed mainly of a protein called tubulin that is found in most eukaryotic cells. An associated pair of centrioles, surrounded by an shapeless mass of dense material, called the pericentriolar material, or PCM, makes up a compound structure called a centrosome.[1]

Centrioles are present in the cells of most eukaryotes, for example those of animals. However, they are absent from conifers (pinophyta), flowering plants (angiosperms) and most fungi, and are only present in the male gametes of charophytes, bryophytes, seedless vascular plants, cycads, and gingko.[2][3]

Most centrioles are made up of nine sets of microtubule triplets, arranged in a cylinder. Deviations from this structure include crabs and Drosophila melanogaster embryos, with nine doublets, and Caenorhabditis elegans sperm cells and early embryos, with nine singlets.[4][5]

Cross-section of a centriole showing its microtubule triplets

Edouard van Beneden and Theodor Boveri made the first observation and identification of centrioles in 1883 and 1888 respectively,[6][7] while the pattern of centriole duplication was first worked out independently by Etienne de Harven and Joseph G. Gall circa 1950 [8][9]

Contents

  • Cell division 1
  • Cellular organization 2
  • Ciliogenesis 3
  • Animal development 4
  • Centriole duplication 5
  • Origin 6
  • References 7

Cell division

Centrioles are involved in the organization of the mitotic spindle and in the completion of cytokinesis.[10] Centrioles were previously thought to be required for the formation of a mitotic spindle in animal cells. However, more recent experiments have demonstrated that cells whose centrioles have been removed via laser ablation can still progress through the G1 stage of interphase before centrioles can be synthesized later in a de novo fashion.[11] Additionally, mutant flies lacking centrioles develop normally, although the adult flies' cells lack flagella and cilia and as a result, they die shortly after birth.[12]

Cellular organization

Centrioles are a very important part of microtubules in the cytoplasm.[13][14] The position of the centriole determines the position of the nucleus and plays a crucial role in the spatial arrangement of the cell.

3D Rendering of Centrioles

Ciliogenesis

In organisms with basal body. An inability of cells to use centrioles to make functional cilia and flagella has been linked to a number of genetic and developmental diseases. In particular, the inability of centrioles to properly migrate prior to ciliary assembly has recently been linked to Meckel-Gruber syndrome.[15]

Animal development

Electron micrograph of a centriole from a mouse embryo.

Proper orientation of cilia via centriole positioning toward the posterior of embryonic node cells is critical for establishing left–right asymmetry during mammalian development.

Centriole duplication

Before DNA replication, cells contain two centrioles. The older of the two centrioles is termed the mother centriole, the other the daughter. During the cell division cycle, a new centriole grows from the side of each mother centriole. After duplication, the two centriole pairs will remain attached to each other orthogonally until mitosis. At that point the mother and daughter centrioles separate dependently on an enzyme called separase.[16]

The two centrioles in the centrosome are tied to one another. The mother centriole has radiating appendages at the distal end of its long axis and is attached to its daughter at the proximal end. Each daughter cell formed after cell division will inherit one of these pairs. Centrioles start duplicating when DNA replicates.[10]

Origin

The last common ancestor of all eukaryotes was a ciliated cell with centrioles. Some lineages of eukaryotes, such as land plants, do not have centrioles except in their motile male gametes. Centrioles are completely absent from all cells of conifers and flowering plants, which do not have ciliate or flagellate gametes.[17] It is unclear if the last common ancestor had one[18] or two cilia.[19] Important genes required for centriole growth, like centrins, are only found in eukaryotes and not in bacteria or archaeans.[18]

References

  1. ^ a b Eddé, B; Rossier, J; Le Caer, JP; Desbruyères, E; Gros, F; Denoulet, P (1990). "Posttranslational glutamylation of alpha-tubulin". Science 247 (4938): 83–5.  
  2. ^ Quarmby, LM; Parker, JD (2005). "Cilia and the cell cycle?". The Journal of Cell Biology 169 (5): 707–10.  
  3. ^ Silflow, CD; Lefebvre, PA (2001). "Assembly and motility of eukaryotic cilia and flagella. Lessons from Chlamydomonas reinhardtii.". Plant Physiology 127: 1500–1507.  
  4. ^ Delattre, M; Gönczy, P (2004). "The arithmetic of centrosome biogenesis". Journal of Cell Science 117 (Pt 9): 1619–30.  
  5. ^ Leidel, S; Delattre, M; Cerutti, L; Baumer, K; Gönczy, P (2005). "SAS-6 defines a protein family required for centrosome duplication in C. elegans and in human cells". Nature Cell Biology 7 (2): 115–25.  
  6. ^ Wunderlich, V. (2002). "JMM - Past and Present". Journal of Molecular Medicine 80 (9): 545–548.  
  7. ^
  8. ^  
  9. ^ Vorobjev, I. A.; Nadezhdina, E. S. (1987). "The Centrosome and Its Role in the Organization of Microtubules". International Review of Cytology. International Review of Cytology 106: 227–293.  
  10. ^ a b Salisbury, JL; Suino, KM; Busby, R; Springett, M (2002). "Centrin-2 is required for centriole duplication in mammalian cells". Current biology : CB 12 (15): 1287–92.  
  11. ^ La Terra, S; English, CN; Hergert, P; McEwen, BF; Sluder, G; Khodjakov, A (2005). "The de novo centriole assembly pathway in HeLa cells: cell cycle progression and centriole assembly/maturation". The Journal of Cell Biology 168 (5): 713–22.  
  12. ^ Basto, R; Lau, J; Vinogradova, T; Gardiol, A; Woods, CG; Khodjakov, A; Raff, JW (2006). "Flies without centrioles". Cell 125 (7): 1375–86.  
  13. ^ Feldman, JL; Geimer, S; Marshall, WF (2007). "The mother centriole plays an instructive role in defining cell geometry". PLoS Biology 5 (6): e149.  
  14. ^ Beisson, J; Wright, M (2003). "Basal body/centriole assembly and continuity". Current opinion in cell biology 15 (1): 96–104.  
  15. ^ Cui, Cheng ; Chatterjee, Bishwanath ; Francis, Deanne ; Yu, Qing ; SanAgustin, Jovenal T. ; Francis, Richard ; Tansey, Terry ; Henry, Charisse ; Wang, Baolin ; Lemley, Bethan ; Pazour, Gregory J. ; Lo, Cecilia W. (2011). "Disruption of Mks1 localization to the mother centriole causes cilia defects and developmental malformations in Meckel-Gruber syndrome". Dis Model Mech 4 (1): 43–56.  
  16. ^ Tsou, MF; Stearns, T (2006). "Mechanism limiting centrosome duplication to once per cell cycle". Nature 442 (7105): 947–51.  
  17. ^ Marshall, W.F. (2009). "Centriole Evolution". Current Opinion in Cell Biology 21 (1): 14–19.  
  18. ^ a b Bornens, M.; Azimzadeh, J. (2007). "Eukaryotic Membranes and Cytoskeleton". Advances in experimental medicine and biology. Advances in Experimental Medicine and Biology 607: 119–129.  
  19. ^ Rogozin, I. B.; Basu, M. K.; Csürös, M.; Koonin, E. V. (2009). "Analysis of Rare Genomic Changes Does Not Support the Unikont-Bikont Phylogeny and Suggests Cyanobacterial Symbiosis as the Point of Primary Radiation of Eukaryotes". Genome Biology and Evolution 1: 99–113.