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Division cellulaire asymétrique

Division cellulaire asymétrique. A. M. B. Sheath. Socket. Shaft. Neuron. pI. Glial. pIIb. pI. pIIIb. Neurone. métaphase. Sheath. Shaft. pIIa. pIIb. Socket. pIIa. télophase. A101 / a -tub / Numb. Répartition inégale des déterminants de l’identité cellulaire.

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Division cellulaire asymétrique

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  1. Division cellulaire asymétrique A M B

  2. Sheath Socket Shaft Neuron

  3. pI Glial pIIb pI pIIIb Neurone métaphase Sheath Shaft pIIa pIIb Socket pIIa télophase A101 / a-tub / Numb

  4. Répartition inégale des déterminants de l’identité cellulaire 1. Polarisation 2. Distribution asymétrique des déterminants 3. Position du site de clivage (répartition inégale) A B

  5. 1. Perte de polarité 2. Défaut dans la position du site de clivage A A A A

  6. Knoblich, 2002

  7. pI Glial pIIb pI pIIIb Neurone métaphase Sheath Shaft pIIa pIIb Socket pIIa télophase A101 / a-tub / Numb

  8. Glial pIIb pI pIIIb Neurone Sheath Shaft wild-type Socket pIIa pIIb pIIa Neurone/Glial Socket pI pI Neurone/Glial Socket Neurone/Glial Socket Neurone/Glial Socket pIIb pIIa numb Notch-Act Notch

  9. wild-type Numb numb Notch Notch (ts) Notch (ts) + numb Jan, 1996

  10. a-adaptin

  11. Numb a-adaptin pIIa pIIb pI pI pIIb pIIa a-adaptin Hs-numb

  12. a-adaptin Notch pIIa pIIb pI pI pIIb pIIa a-adaptin Notch (ts) - 29°C

  13. pIIb pIIa Numb a-adaptin Notch Numb Notch • • • • • • • pIIb pIIa

  14. Pon-GFP

  15. pI pI apical epidermal anterior posterior basal Pon-GFP Histone2B-YFP

  16. Planar polarity in Drosophila frizzled flamingo strabismus dishevelled prickle Pk Stbm Fz Dsh

  17. Pk, Stbm Fz Polar distribution of planar polarity proteins Stbm H2B-YFP GFP-Stbm H2B-YFP Fz-GFP pI pI

  18. Planar polarity genes orient pI cells a-tubulin Numb random frizzled flamingo strabismus dishevelled prickle wild-type

  19. anterior posterior Fz, Dsh Stbm, Pk orientation (prior to mitosis) ? Numb

  20. Les neuroblastes de l’embryon de Drosophile VNE épiderme Temps neuroblaste GCM neurones

  21. Le déterminant Prospero sauvage prospero Neuroblaste spécifique : dpn,ase GMC spécifique : eve,ftz

  22. GMC Nbs Prospero Miranda

  23. The mitotic spindle rotates by 0-90° - Centrosomes are randomly positioned at separation - Centrosomes migrate by the shortest path to orient the spindle No evidence for centrosome priming

  24. Identification du gène inscuteable

  25. Inscuteable se localise au pôle apical interphase prophase métaphase anaphase

  26. Inscuteable est requis pour localiser Miranda Insc- Miranda/ADN

  27. Baz DmPKC DmPar6 Baz DmPKC DmPar6 -Localisation de Miranda -Rotation du fuseau Inscuteable Inscuteable Pins-GaiGDP Gai/Gß Cibles?

  28. Drosophila neuroblasts Chia, Doe, Jan, Knoblich, Knust ... apical cue Bazooka (PAR-3) DmPAR-6 DaPKC Mitotic spindle rotation Basal accumulation of Numb andProspero Inscuteable Pins Gai-GDP + Gbg

  29. Planar polarity in Drosophila frizzled flamingo strabismus dishevelled prickle Pk Stbm Fz Dsh

  30. Planar polarity genes orient pI cells a-tubulin Numb random frizzled flamingo strabismus dishevelled prickle wild-type

  31. Baz PAR-6 aPKC Pins Gai-GDP Gbg effectors aPKC targets Numb bazooka and pins are required to localize Numb ... wild-type pins pins baz Numb Numb Numb

  32. Establishment of polarity in pI cells and in neuroblasts Planar polarity signal Apical signal Bazooka DaPKC DmPAR-6 (posterior) Bazooka DaPKC DmPAR-6 (apical) Dlg-Pins (anterior) Inscuteable Pins pI Neuroblast Numb localises opposite to Baz

  33. WT WT Inscuteable reverts pI cell polarity Dlg-Pins NumbPins NumbInsc UAS-Insc UAS-Insc Inscuteable Bazooka DaPKC DmPAR-6 (anterior) Insc NumbPins UAS-Insc UAS-Insc Numb (posterior) Baz Dlg

  34. Numb (drosophile-mammifères: 603 aa) PTB Neurorétine

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