1. Presented by Juan Mo

2. Study Questions Why zebrafish transgenetic lines are very important for studying photoreceptor degeneration? The synapses in inner plexiform layer and in outer plexiform layer? ON bipolar cell & OFF bipolar cell? What are the larval and adult phenotypes of pde6c w59 and Xops:mCFP q13 lines? Light and dark preference test? How does morpholino injection knock down gene expression?

3. Contains red, green, blue and UV cone cells Contains rods Zebrafish: outstanding model studying photoreceptor degenerations Advantages: Ex utero rapid development Optical transparency Permeability to drugs Ease of making transgenetic animal The acute visual abilities of larvae adult larvae

4. pde6c w59 transgenic line cone degeneration death of rod (larvae) rod persistence (juvenile and adult) Xops:mCFP q13 transgenic line rod degeneration loss of cone (mammanlian) cone unaffected (zebrafish)

5. Hypothesis Rod photoreceptors protects from cone degeneration-induced retinal remodeling and restore visual responses in zebrafish

7. http://what-when-how.com/neuroscience/visual-system-sensory-system-part-2/

8. K+ metabotropic glutamate receptor ionotropic glutamate receptor Na+ http://what-when-how.com/neuroscience/visual-system-sensory-system-part-2/

9. ON OFF http://webvision.med.utah.edu/book/part-ii-anatomy-and-physiology-of-the-retina/oute-plexiform/ ribbon M A B

10. Confocal Microscopy

11. Result 1: development of ON bipolar cell contacts with rod and cone photoreceptors cones rods ON bipolar cell OPL Cone pedicle Rod spherule dendrites ON bipolar cell cones rods nyx:mYFP q16

12. Result 2: cone degeneration in pde6 cw59 mutant larvae leads to ON bipolar cell remodeling rods cones ON bipolar cell pde6 cw59 transgenic cone degeneration Xops:mCFPq13 transgenic rod degeneration

13. D6 D8 Result 2: cone degeneration in pde6 cw59 mutant larvae leads to ON bipolar cell remodeling pde6 cw59 transgenic cone degeneration Xops:mCFPq13 transgenic rod degeneration 8 DPF ON bipolar axon terminals 6 DPF

14. Result 3: postsynaptic glutamate receptor expression is altered in pde6c w59 larvae OFF bipolar cell ON bipolar cell horizontal cell D6 D8 pde6 cw59 transgenic cone degeneration Xops:mCFPq13 transgenic rod degeneration 8 DPF 6 DPF

15. Result 4: synaptic structure is maintained in Xops:mCFP q13 and pde6c w59 adults cones ON bipolar cell cones ON bipolar cell

16. Result 4: synaptic structure is maintained in Xops:mCFP q13 and pde6c w59 adults photoreceptor terminals horizontal cell rod spheruleCone pedicle photoreceptor terminals horizontal cell

17. Result 5: visual responses are preserved in pde6c w59 mutant adults diffuse white light

18. Optokinetic response (OKR): http://www.youtube.com/watch?v=mfstlvsW1IY WT and pde6cw59 adults display a robust OKR. Result 5: visual responses are preserved in pde6c w59 mutant adults

19. Result 6: increased rod number protects the larval retina from cone degeneration- induced remodeling rod ON bipolar cell nuclear

20. Morpholino: knock down gene translation

21. Conclusion Cone degeneration leads to ON bipolar cell remodeling in larvae. Although the neural connectivity remains intact, the loss of the majority of the presynaptic input leads to significant remodeling observed in cone degeneration adult. Visual responses are preserved in cone degeneration adult. Increased rod number protects the larval retina from cone degeneration-induced remodeling. ? Rod photoreceptors protects from cone degeneration- induced retinal remodeling and restore visual responses in zebrafish

22. Review Questions Why zebrafish transgenetic lines are very important for studying photoreceptor degeneration? The synapses in inner plexiform layer and in outer plexiform layer? ON bipolar cell & OFF bipolar cell? What are the larval and adult phenotypes of pde6c w59 and Xops:mCFP q13 lines? Light and dark preference test? How does morpholino injection knock down gene expression?