A phenotypic and molecular characterization of the fmr1-tm1Cgr Fragile X mouse

Bauchwitz, Dr. Robert P. (2004) A phenotypic and molecular characterization of the fmr1-tm1Cgr Fragile X mouse. [Journal (Paginated)]

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Fragile X Syndrome is the most common form of inherited mental retardation. It is also known for having a substantial behavioral morbidity, including autistic features. In humans, Fragile X Syndrome is almost always caused by inactivation of the X-linked FMR1 gene. A single knockout mouse model, fmr1-tm1Cgr, exists. In this report we further characterize the cognitive and behavioral phenotype of the fmr1-tm1Cgr Fragile X mouse through the use of F1 hybrid mice derived from two inbred strains (FVB/NJ and C57BL/6J). Use of F1 hybrids allows focus on the effects of the fmr1-tm1Cgr allele with reduced influence from recessive alleles present in the parental inbred strains. We find that the cognitive phenotype of fmr1-tm1Cgr mice, including measures of working memory and learning set formation that are known to be seriously impacted in humans with Fragile X Syndrome, are essentially normal. Further testing of inbred strains supports this conclusion. Thus, any fmr1-tm1Cgr cognitive deficit is surprisingly mild or absent. There is, however, clear support presented for a robust audiogenic seizure phenotype in all strains tested, as well as increased entries into the center of an open field. Finally, a molecular examination of the fmr1-tm1Cgr mouse shows that, contrary to common belief, it is not a molecular null. Implications of this finding for interpretation of the phenotype are discussed.

Item Type:Journal (Paginated)
Keywords:audiogenic seizure, Barnes maze, Fmr1 RNA, Fragile X, hybrid mouse strain, Morris water maze, olfactory sequence learning, open field, radial maze, working memory
Subjects:Neuroscience > Behavioral Neuroscience
ID Code:6539
Deposited By: Bauchwitz, Robert
Deposited On:10 Jun 2009 08:01
Last Modified:11 Mar 2011 08:57


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