Elevated expression of the G-protein-activated inwardly rectifying potassium channel 2 (GIRK2) in cerebellar unipolar brush cells of a down syndrome mouse model

被引：31

作者：

Chie Harashima ^{[2
]}

David M. Jacobowitz ^{[2
]}

Markus Stoffel ^{[3
]}

Lina Chakrabarti ^{[4
]}

Tarik F. Haydar ^{[5
]}

Richard J. Siarey ^{[5
]}

Zygmunt Galdzicki ^{[2
]}

机构：

[1] Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, School of Medicine, Bethesda

[2] Laboratory of Clinical Science, National Institute of Mental Health, National Institutes of Health, Bethesda, MD

[3] Laboratory of Metabolic Diseases and Molecular Cell Biology, Rockefeller University, New York

[4] Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC

来源：

Cellular and Molecular Neurobiology | 2006年 / 26卷 / 4期

基金：

美国国家卫生研究院;

关键词：

Cerebellum; Dorsal cochlear nucleus; Down syndrome; G-protein activated inwardly rectifying potassium channel; GIRK; Girk2 knockout mouse; Potassium channel; Trisomy; Ts65Dn; Unipolar brush cells; Vestibulocerebellum;

D O I：

10.1007/s10571-006-9066-4

中图分类号：

学科分类号：

摘要：

1. Down syndrome (DS) arises from the presence of three copies of chromosome (Chr.) 21. Fine motor learning deficits found in DS from childhood to adulthood result from expression of extra genes on Chr. 21, however, it remains unclear which if any of these genes are the specific causes of the cognitive and motor dysfunction. DS cerebellum displays morphological abnormalities that likely contribute to the DS motor phenotype. 2. The G-protein-activated inwardly rectifying potassium channel subunit 2 (GIRK2) is expressed in cerebellum and can shunt dendritic conductance and attenuate postsynaptic potentials. We have used an interbreeding approach to cross a genetic mouse model of DS (Ts65Dn) with Girk2 knockout mice and examined its relative expression level by quantitative real-time RT-PCR, Western blotting and immunohistochemistry. 3. We report here for the first time that GIRK2 is expressed in unipolar brush cells, which are excitatory interneurons of the vestibulocerebellum and dorsal cochlear nucleus. Analysis of disomic-Ts65Dn/Girk2(+/+/-) and heterozygous-Diploid/Girk2(+/-) mice shows that GIRK2 expression in Ts65Dn lobule X follows gene dosage. The lobule X of Ts65Dn mice contain greater numbers of unipolar brush cells co-expressing GIRK2 and calretinin than the control mouse groups. 4. These results demonstrate that gene triplication can impact specific cell types in the cerebellum. We hypothesize that GIRK2 overexpression will adversely affect cerebellar circuitry in Ts65Dn vestibulocerebellum and dorsal cochlear nucleus due to GIRK2 shunting properties and its effects on resting membrane potential. © 2006 Springer Science+Business Media, Inc.

引用

页码：719 / 734

页数：15

共 55 条

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