Fragile X-related proteins regulate mammalian circadian behavioral rhythms.

ABSTRACT: Fragile X syndrome results from the absence of the fragile X mental retardation 1 (FMR1) gene product (FMRP). FMR1 has two paralogs in vertebrates: fragile X related gene 1 and 2 (FXR1 and FXR2). Here we show that Fmr1/Fxr2 double knockout (KO) and Fmr1 KO/Fxr2 heterozygous animals exhibit a loss of rhythmic activity in a light:dark (LD) cycle, and that Fmr1 or Fxr2 KO mice display a shorter free-running period of locomotor activity in total darkness (DD). Molecular analysis and in vitro electrophysiological studies suggest essentially normal function of cells in the suprachiasmatic nucleus (SCN) in Fmr1/Fxr2 double KO mice. However, the cyclical patterns of abundance of several core clock component messenger (m) RNAs are altered in the livers of double KO mice. Furthermore, FXR2P alone or

SUBMITTER: Zhang J 

PROVIDER: S-EPMC2443847 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature