1. The FMR1 disorders (Fragile X syndrome, etc)

2. Mary Beth Busby founding board member of the Fragile X Research Foundation (FRAXA) Walter Kaufmann Director, Center for Genetic Disorders of Cognition and Behavior, Kennedy Krieger Institute, The Johns Hopkins UniversityCenter for Genetic Disorders of Cognition and Behavior Karen Usdin Chief, Gene Structure and Disease Section LMCB, NIDDK

3. Understanding the molecular basis of the FMR1 gene disorders Karen Usdin 5’ UTR exon 1 intron 1 (CGG)n promoter X chromosome

4. FXPOI

5. The Repeat Expansion Diseases Myotonic dystrophy type 1 Myotonic dystrophy type 1 Also: SCA 8, SCA12, and HDL2 FMR1 disorders Friedreich ataxia Haw River Syndrome (DRPLA) (DRPLA) Huntington disease SCA 1, 2, 6, 7 Kennedy Disease (SBMA) (SBMA) Progressive myoclonus epilepsy FRAXE MR SCA10SCA10 Myotonic dystrophy type 2 Myotonic dystrophy type 2 OR Promoter5’ UTR ORF3’ UTRIntron (CGG) n (CTG) n (CAG) n (GAA) n (ATTCT) n (C 4 GC 4 GCG) n (CCTG) n

7. gametogenesis

8. Premutation symptoms result from RNA “toxicity” The RNA is somehow deleterious the CGG-repeats may trigger deleterious processes sequester proteins that are important for normal neuronal and ovarian function

11. RNA “toxicity” hypothesis The RNA is somehow deleterious the CGG-repeats may initiate or trigger deleterious processes the CGG-repeats may sequester proteins that are important for normal neuronal and ovarian function

13. RNA interference Hannon (2002)

14. SK cells DAPI lamin merge SK cells+CGG 88

15. Is FXTAS a laminopathy? mutations in Lamin A/C are associated with one form of Charcot-Marie-Tooth disease, a neurological disorder other mutations in Lamin A/C result in premature aging

18. Gene silencing in mammals DNA methylation Histone modifications

19. Science, 1991

20. 5-azadeoxycytidine

22. What does FMRP do?

23. learning difficulties macroorchidism altered circadian rhythms rapid early growth rate audiogenic seizures anxiety

24. Qin and Beebe-Smith (NIMH) WT KO

25. FMRP structure NDF

26. RNAs bound by FMRP FMR1 Glucocorticoid receptor GABA A receptor subunits CAMKIIα MAP1B Rac1 Calbindin Vimentin etc, etc

27. protein product Protein gel - FMRP FMRPI304N

28. Increased rates of cerebral glucose metabolism in a mouse model of fragile X mental retardation Qin, Kang, and Beebe Smith (2002) (NIMH) WT KO Nissl staining [ 14 C] DG

29. Results of “fishing” for FMRP interacting proteins FXR1P FXR2P CYFIP1 and CYFIP2 Poly(A)-binding protein eIF2C2/AGO1 Dicer kinesin heavy chain

31. RNA interference Hannon (2002)

32. axon dendrite synapse

33. Grazyna Gorny

34. Synaptic transmission

35. FXSUn Dendritic Spine Structural Anomalies in Fragile-X Mental Retardation Syndrome Irwin, Galvez and William T. Greenough Cerebral Cortex (2000)

36. Results of “fishing” for FMRP interacting proteins FXR1P FXR2P CYFIP1 and CYFIP2 Poly(A)-binding protein eIF2C2/AGO1 Dicer kinesin heavy chain

37. FMRP RISC

38. mGluR5 receptor

41. WT FX MG +/- FX/MG +/-

47. Minocycline

48. Metalloproteinase-9 (MMP-9)

50. Take home messages FXTAS and FXPOI result from repeat-induced hyperexpression of the FMR1 gene and the deleterious effects of high levels of CGG-repeat containing mRNA. FXS results from repeat-induced gene silencing. silencing leads to a deficiency of FMRP, a protein important for the regulation of translation in the synapses of neurons the resultant abnormal expression of proteins like mGluR5, GSK-3, GABA A and MMP-9 results in the symptoms of FXS normalizing expression of these proteins may provide targeted approaches to the treatment of FXS.