Somatosensory cortical barrel dendritic abnormalities in a mouse model of the fragile X mental retardation syndrome.
The Fragile X mental retardation syndrome is the largest source of inherited mental retardation. The syndrome usually results from the transcriptional silencing of the fragile X mental retardation gene (FMR1). To date the most prominent reported neuronal abnormalities for the fragile X mental retardation syndrome include a higher density of long thin spines similar to those found in sensory deprived and developing tissue, suggesting a possible deficit in pruning of immature spines. Dendrites on spiny stellate cells in the inner 1/3 of the barrel wall in layer IV of the rodent somatosensory cortex have been shown to exhibit developmental pruning similar to that affecting spines. To determine if FMRP plays a role in dendritic development, these neurons were examined in two strains of adult FMRP knockout (FraX) mice. FraX mice in both strains exhibited a greater amount of septa-oriented dendritic material, a morphology consistent with pre-pruning status early in development. This observation suggests that FMRP could be necessary for normal developmentally regulated dendritic pruning.
Galvez
Roberto
R
Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. rgalvez@uiuc.edu
Gopal
Anjali R
AR
Greenough
William T
WT
D000818:Animals; D003712:Dendrites / Q000473:pathology*; D051860:Fragile X Messenger Ribonucleoprotein 1; D005600:Fragile X Syndrome / Q000473:pathology*; D051379:Mice; D018345:Mice, Knockout; D023421:Models, Animal; D009419:Nerve Tissue Proteins / Q000172:deficiency*; D016601:RNA-Binding Proteins; D013003:Somatosensory Cortex / Q000473:pathology* / Q000648:ultrastructure
D051860:Fragile X Messenger Ribonucleoprotein 1; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C497684:Fmr1 protein, mouse