The transcription factor forkhead box O6 is expressed primarily in the central nervous system (predominantly in the hippocampal CA1 and CA3 regions), and is negatively regulated by the insulin and insulin-like growth factor (IGF) signaling pathway. These mice carry a targeted mutation of the mouse Foxo6, forkhead box O6, gene in which a NEO cassette replaced exon 1. Mice that are homozygous for this targeted mutation are viable and fertile, but have smaller litter sizes compared to wildtype controls. No full-length gene product (mRNA or protein) is detected by Western blot analysis of the anterior brain, cortex, hippocampus and testes or by RT-PCR analysis of hippocampus. Homozygotes exhibit impaired memory consolidation, as indicated by contextual memory tests. Reduced dendritic spine density of hippocampal neurons is observed in cultured hippocampal neurons and dendritic spine length is also increased in the CA1 region of homozygous mice. During backcrossing, the Y chromosome may not have been fixed to the C57BL/6J genetic background.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This is the case for the strain above. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
