title: Selective rescue of heightened anxiety but not gait ataxia in a premutation 90CGG mouse model of Fragile X-associated tremor/ataxia syndrome.
abstract: A CGG-repeat expansion in the premutation range in the Fragile X mental retardation 1 gene (FMR1) has been identified as the genetic cause of Fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder that manifests with action tremor, gait ataxia and cognitive impairments. In this study, we used a bigenic mouse model, in which expression of a 90CGG premutation tract is activated in neural cells upon doxycycline administration-P90CGG mouse model. We, here, demonstrate the behavioural manifestation of clinically relevant features of FXTAS patients and premutation carrier individuals in this inducible mouse model. P90CGG mice display heightened anxiety, deficits in motor coordination and impaired gait and represent the first FXTAS model that exhibits an ataxia phenotype as observed in patients. The behavioural phenotype is accompanied by the formation of ubiquitin/FMRpolyglycine-positive intranuclear inclusions, as another hallmark of FXTAS, in the cerebellum, hippocampus and amygdala. Strikingly, upon cessation of transgene induction the anxiety phenotype of mice recovers along with a reduction of intranuclear inclusions in dentate gyrus and amygdala. In contrast, motor function deteriorates further and no reduction in intranuclear inclusions can be observed in the cerebellum. Our data thus demonstrate that expression of a 90CGG premutation expansion outside of the FMR1 context is sufficient to evoke an FXTAS-like behavioural phenotype. Brain region-specific neuropathology and (partial) behavioural reversibility make the inducible P90CGG a valuable mouse model for testing pathogenic mechanisms and therapeutic intervention methods.
authors.affiliation: Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
authors.forename: Hoanna
authors.initials: H
authors.lastname: Castro
authors.affiliation: Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
authors.forename: Emre
authors.initials: E
authors.lastname: Kul
authors.affiliation: Department of Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands.
authors.forename: Ronald A M
authors.initials: RAM
authors.lastname: Buijsen
authors.affiliation: Department of Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands.
authors.forename: Lies-Anne W F M
authors.initials: LWFM
authors.lastname: Severijnen
authors.affiliation: Department of Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands.
authors.forename: Rob
authors.initials: R
authors.lastname: Willemsen
authors.affiliation: Department of Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands.
authors.forename: Renate K
authors.initials: RK
authors.lastname: Hukema
authors.affiliation: Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany.|Center for Behavioral Brain Sciences, Magdeburg.
authors.forename: Oliver
authors.initials: O
authors.lastname: Stork
authors.affiliation: Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
authors.forename: Mónica
authors.initials: M
authors.lastname: Santos
mesh_terms: D000818:Animals; D001007:Anxiety / Q000235:genetics / Q000378:metabolism; D001259:Ataxia / Q000235:genetics* / Q000378:metabolism; D001921:Brain / Q000473:pathology; D002524:Cerebellar Ataxia / Q000235:genetics; D003072:Cognition Disorders / Q000235:genetics; D004195:Disease Models, Animal; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics* / Q000378:metabolism; D005600:Fragile X Syndrome / Q000235:genetics* / Q000378:metabolism; D005684:Gait; D020234:Gait Ataxia / Q000235:genetics / Q000378:metabolism; D045586:Intranuclear Inclusion Bodies / Q000235:genetics; D051379:Mice; D009069:Movement Disorders / Q000235:genetics; D009474:Neurons / Q000473:pathology; D014202:Tremor / Q000235:genetics* / Q000378:metabolism; D019680:Trinucleotide Repeat Expansion / Q000235:genetics
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; C497684:Fmr1 protein, mouse