title: Deletion of FMR1 in Purkinje cells enhances parallel fiber LTD, enlarges spines, and attenuates cerebellar eyelid conditioning in Fragile X syndrome.
abstract: Absence of functional FMRP causes Fragile X syndrome. Abnormalities in synaptic processes in the cerebral cortex and hippocampus contribute to cognitive deficits in Fragile X patients. So far, the potential roles of cerebellar deficits have not been investigated. Here, we demonstrate that both global and Purkinje cell-specific knockouts of Fmr1 show deficits in classical delay eye-blink conditioning in that the percentage of conditioned responses as well as their peak amplitude and peak velocity are reduced. Purkinje cells of these mice show elongated spines and enhanced LTD induction at the parallel fiber synapses that innervate these spines. Moreover, Fragile X patients display the same cerebellar deficits in eye-blink conditioning as the mutant mice. These data indicate that a lack of FMRP leads to cerebellar deficits at both the cellular and behavioral levels and raise the possibility that cerebellar dysfunctions can contribute to motor learning deficits in Fragile X patients.
authors.affiliation: Department of Neuroscience, Erasmus MC, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
authors.forename: S K E
authors.initials: SK
authors.lastname: Koekkoek
authors.forename: K
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: B A
authors.initials: BA
authors.lastname: Milojkovic
authors.forename: B R
authors.initials: BR
authors.lastname: Dortland
authors.forename: T J H
authors.initials: TJ
authors.lastname: Ruigrok
authors.forename: R
authors.initials: R
authors.lastname: Maex
authors.forename: W
authors.initials: W
authors.lastname: De Graaf
authors.forename: A E
authors.initials: AE
authors.lastname: Smit
authors.forename: F
authors.initials: F
authors.lastname: VanderWerf
authors.forename: C E
authors.initials: CE
authors.lastname: Bakker
authors.forename: R
authors.initials: R
authors.lastname: Willemsen
authors.forename: T
authors.initials: T
authors.lastname: Ikeda
authors.forename: S
authors.initials: S
authors.lastname: Kakizawa
authors.forename: K
authors.initials: K
authors.lastname: Onodera
authors.forename: D L
authors.initials: DL
authors.lastname: Nelson
authors.forename: E
authors.initials: E
authors.lastname: Mientjes
authors.forename: M
authors.initials: M
authors.lastname: Joosten
authors.forename: E
authors.initials: E
authors.lastname: De Schutter
authors.forename: B A
authors.initials: BA
authors.lastname: Oostra
authors.forename: M
authors.initials: M
authors.lastname: Ito
authors.forename: C I
authors.initials: CI
authors.lastname: De Zeeuw
mesh_terms: D000818:Animals; D002531:Cerebellum / Q000503:physiopathology*; D003215:Conditioning, Eyelid; D003712:Dendrites / Q000648:ultrastructure; D051860:Fragile X Messenger Ribonucleoprotein 1; D005600:Fragile X Syndrome / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D017353:Gene Deletion; D006801:Humans; D036881:Long-Term Synaptic Depression; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D008959:Models, Neurological; D009412:Nerve Fibers; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D011689:Purkinje Cells / Q000378:metabolism* / Q000648:ultrastructure; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D013216:Reflex, Startle
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C497683:FMR1 protein, human; C497684:Fmr1 protein, mouse