title: Spontaneous shaker rat mutant - a new model for X-linked tremor/ataxia.
abstract: The shaker rat is an X-linked recessive spontaneous model of progressive Purkinje cell (PC) degeneration exhibiting a shaking ataxia and wide stance. Generation of Wistar Furth (WF)/Brown Norwegian (BN) F1 hybrids and genetic mapping of F2 sib-sib offspring using polymorphic markers narrowed the candidate gene region to 26 Mbp denoted by the last recombinant genetic marker DXRat21 at 133 Mbp to qter (the end of the long arm). In the WF background, the shaker mutation has complete penetrance, results in a stereotypic phenotype and there is a narrow window for age of disease onset; by contrast, the F2 hybrid phenotype was more varied, with a later age of onset and likely non-penetrance of the mutation. By deep RNA-sequencing, five variants were found in the candidate region; four were novel without known annotation. One of the variants caused an arginine (R) to cysteine (C) change at codon 35 of the ATPase, Ca(2+) transporting, plasma membrane 3 (Atp2b3) gene encoding PMCA3 that has high expression in the cerebellum. The variant was well supported by hundreds of overlapping reads, and was found in 100% of all affected replicas and 0% of the wild-type (WT) replicas. The mutation segregated with disease in all affected animals and the amino acid change was found in an evolutionarily conserved region of PMCA3. Despite strong genetic evidence for pathogenicity, in vitro analyses of PMCA3(R35C) function did not show any differences to WT PMCA3. Because Atp2b3 mutation leads to congenital ataxia in humans, the identified Atp2b3 missense change in the shaker rat presents a good candidate for the shaker rat phenotype based on genetic criteria, but cannot yet be considered a definite pathogenic variant owing to lack of functional changes.
authors.affiliation: Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Karla P
authors.initials: KP
authors.lastname: Figueroa
authors.affiliation: Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Sharan
authors.initials: S
authors.lastname: Paul
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Tito
authors.initials: T
authors.lastname: Calì
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Lopreiato
authors.affiliation: Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Sukanya
authors.initials: S
authors.lastname: Karan
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Frizzarin
authors.affiliation: Bioinformatics Shared Resource, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Darren
authors.initials: D
authors.lastname: Ames
authors.affiliation: Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Ginevra
authors.initials: G
authors.lastname: Zanni
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Marisa
authors.initials: M
authors.lastname: Brini
authors.affiliation: Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Warunee
authors.initials: W
authors.lastname: Dansithong
authors.affiliation: Bioinformatics Shared Resource, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Brett
authors.initials: B
authors.lastname: Milash
authors.affiliation: Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Scoles
authors.affiliation: Venetian Institute of Molecular Medicine (VIMM), Padova, Italy.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Carafoli
authors.affiliation: Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA stefan.pulst@hsc.utah.edu.
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Pulst
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002118:Calcium / Q000378:metabolism; D002524:Cerebellar Ataxia / Q000235:genetics* / Q000473:pathology*; D002874:Chromosome Mapping; D004195:Disease Models, Animal; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000378:metabolism; D005816:Genetic Complementation Test; D040181:Genetic Diseases, X-Linked / Q000473:pathology*; D006801:Humans; D008297:Male; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000378:metabolism; D011689:Purkinje Cells / Q000473:pathology; D011920:Rats, Inbred WF; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D017423:Sequence Analysis, RNA; D014202:Tremor / Q000235:genetics* / Q000473:pathology*; D019680:Trinucleotide Repeat Expansion / Q000235:genetics
chemical_list: D002118:Calcium; D051860:Fragile X Messenger Ribonucleoprotein 1; D050505:Mutant Proteins; D053499:Plasma Membrane Calcium-Transporting ATPases; C497685:Fmr1 protein, rat
keywords: Ataxia; Atp2b3; PMCA3; X-linked; shaker