title: The FMR1 CGG repeat mouse displays ubiquitin-positive intranuclear neuronal inclusions; implications for the cerebellar tremor/ataxia syndrome.
abstract: Recent studies have reported that alleles in the premutation range in the FMR1 gene in males result in increased FMR1 mRNA levels and at the same time mildly reduced FMR1 protein levels. Some elderly males with premutations exhibit an unique neurodegenerative syndrome characterized by progressive intention tremor and ataxia. We describe neurohistological, biochemical and molecular studies of the brains of mice with an expanded CGG repeat and report elevated Fmr1 mRNA levels and intranuclear inclusions with ubiquitin, Hsp40 and the 20S catalytic core complex of the proteasome as constituents. An increase was observed of both the number and the size of the inclusions during the course of life, which correlates with the progressive character of the cerebellar tremor/ataxia syndrome in humans. The observations in expanded-repeat mice support a direct role of the Fmr1 gene, by either CGG expansion per se or by mRNA level, in the formation of the inclusions and suggest a correlation between the presence of intranuclear inclusions in distinct regions of the brain and the clinical features in symptomatic premutation carriers. This mouse model will facilitate the possibilities to perform studies at the molecular level from onset of symptoms until the final stage of the disease.
authors.affiliation: CBG-Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Rob
authors.initials: R
authors.lastname: Willemsen
authors.forename: Marianne
authors.initials: M
authors.lastname: Hoogeveen-Westerveld
authors.forename: Surya
authors.initials: S
authors.lastname: Reis
authors.forename: Joan
authors.initials: J
authors.lastname: Holstege
authors.forename: Lies-Anne W F M
authors.initials: LA
authors.lastname: Severijnen
authors.forename: Ingeborg M
authors.initials: IM
authors.lastname: Nieuwenhuizen
authors.forename: Mariette
authors.initials: M
authors.lastname: Schrier
authors.forename: Leontine
authors.initials: L
authors.lastname: van Unen
authors.forename: Flora
authors.initials: F
authors.lastname: Tassone
authors.forename: Andre T
authors.initials: AT
authors.lastname: Hoogeveen
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Hagerman
authors.forename: Edwin J
authors.initials: EJ
authors.lastname: Mientjes
authors.forename: Ben A
authors.initials: BA
authors.lastname: Oostra
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism* / Q000473:pathology; D002524:Cerebellar Ataxia / Q000235:genetics*; D051860:Fragile X Messenger Ribonucleoprotein 1; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D016601:RNA-Binding Proteins; D019680:Trinucleotide Repeat Expansion; D025801:Ubiquitin / Q000378:metabolism*
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D025801:Ubiquitin; C497683:FMR1 protein, human; C497684:Fmr1 protein, mouse