"6539","A phenotypic and molecular characterization of the fmr1-tm1Cgr Fragile X mouse","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.  ","http://cogprints.org/6539/","Bauchwitz, Dr. Robert P.","UNSPECIFIED","       <span class=\"person_name\">Bauchwitz, Dr. Robert P.</span>     (2004)  <a href=\"http://cogprints.org/6539/\"><em>A phenotypic and molecular characterization of the fmr1-tm1Cgr Fragile X mouse.</em></a>       [Journal (Paginated)]           ","rpb3@columbia.edu","2004-05-10"