FMR2 function: insight from a mouse knockout modelGu Y. · Nelson D.L.
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX (USA)
The FMR2 gene is dysregulated by the fragile X E triplet repeat expansion in patients with FRAXE mental retardation syndrome. A CCG triplet, located in the 5′ untranslated region of the FRAXE gene undergoes expansion and methylation in these patients, eliminating detectable gene transcription. FRAXE syndrome is distinct from fragile X syndrome, a more common genetic form of mental retardation caused by expansion and methylation of a similar repeat in the FMR1 gene located 600 kb proximal to FRAXE. FRAXE syndrome is rare, and patients’ phenotypes are highly variable, leading to difficulties with predicting specific FMR2 functions based on the human disease. Recently, Lilliputian(Lilli), a Drosophila FMR2 orthologue, was identified; this gene has been linked with several signal transduction pathways, including the transforming growth factor-β (TGF-β) pathway, the Raf/MEK/MAP kinase (MAPK) pathway, and the P13K/PKB pathway. Mutation of Lilli shows defects in germinal band extension, cytoskeletal structure, cell growth, and organ development. The Lilli gene suggests possible functions for FMR2 (and related genes) in humans and mice, but cannot predict specific functions. Modeling Fmr2 mutation in the mouse will be useful to understand specific functions of this gene in vertebrates. This review presents what has been learned thus far from the Fmr2 knockout mouse model and suggests future studies on this model in order to compare it with the human FRAXE mental retardation disorder, Lilli mutants in Drosophila and other mouse models of genes in this family.
Request reprints from David L. Nelson, Ph.D.
Department of Molecular and Human Genetics
Room 904E, Baylor College of Medicine
Houston, TX 77030 (USA)
telephone: 713-798-4787; fax: 713-798-1116
Supported by NIH grant HD29256.
Received 17 February 2003;
manuscript accepted 28 February 2003.
Number of Print Pages : 11
Number of Figures : 4, Number of Tables : 1, Number of References : 70
Cytogenetic and Genome Research
Formerly ‘Cytogenetics and Cell Genetics’
Vol. 100, No. 1-4, Year 2003 (Cover Date: 2003)
Journal Editor: H.P. Klinger, Bronx, N.Y.; M. Schmid, Würzburg
ISSN: 1424–8581 (print), 1424–859X (Online)
For additional information: http://www.karger.com/journals/cgr