1. Chapter 4 The Emergence of Neural Fate

4. PNS Neurons in one Abdominal Hemisegment d v’ l v

5. Neurogenesis Lateral inhibition (Notch, delta) Proneural gene expression (achaete, scute) Asymmetric cell division (numb, Notch) SOP pIIa pIIb socket hairsheath neuron Proneural cluster SOP (sensory organ precursor)

6. achaete scute atonal amos Proneural genes Sensory organs + associated MD neurons solo-MD neurons

7. 93% 91% 50% 26~30% 63% 60% achaete scute atonal amos Proneural genes encode basic-helix-loop-helix proteins bHLH

8. Determination of SOP cells

12. Regulation of proneural genes

13. atonal amos coeloconica trichodea basiconica The development of olfactory sensilla From Goulding et al (2000)

18. Neurogenesis Lateral inhibition (Notch, delta) Proneural gene expression (achaete, scute) Asymmetric cell division (numb, Notch) SOP pIIa pIIb socket hairsheath neuron Proneural cluster SOP (sensory organ precursor)

19. Neurogenic mutants Wild type mutants

22. E(spl) Su(H) Delta Notch E(spl) achaete, scute Notch signalinig

23. Notch signaling pathway leads to downregulation of proneural genes

26. sheath hair socket neuron glia ES organ IIBIIA hso shn g SOP Asymmetric Cell Division

29. Numb SOP Asymmetric localization Notch Numb IIAIIB Cell fate determination

32. Insc organizer Spindle orientation Pon Numb Miranda Prospero Staufan Prospero mRNA Dlg Lgl Apical Basal