Annual Meeting of the Society for Neuroscience edition:33 location:New Orleans, U.S.A. date:November 8-12, 2003
The functional properties and anatomical organization of mammalian visual cortex are immature at birth and develop gradually during the first postnatal weeks. The development to the adult state depends at least in part upon visual experience during an early phase of plasticity called the ‘critical period’. Because the family of collapsin response mediator proteins (CRMP) are known to be involved in growth cone collapse and neuronal differentiation we wanted to study their role in development- and plasticity-related structural changes in cat visual cortex. Indeed, previous proteomic experiments showed already that CRMP1, 4 and 5 were more abundantly expressed in kitten visual cortex at postnatal day 30 (J. Neurochem. (2003) 85:193-205). We first studied the distribution of CRMPs in different cortical and subcortical areas with in situ hybridization. While CRMP3 could not be detected, we found a specific distribution pattern for CRMP1, 2, 4 and 5 throughout the cat brain. The expression level was always higher in kitten compared to adult visual cortex and each CRMP showed a specific laminar localization in area 17. Secondly, after determining the specificity of antibodies for cat CRMP2, 4 and 5 with 2D-electrophoresis, we performed Western blotting to quantify age-related expression changes. CRMP4 expression was more than 5 times higher in young animals while CRMP5 was 8 times higher compared to adult visual cortex. For CRMP2 we could detect differences in posttranslational modifications for kitten versus adult area 17. Preliminary results revealed that the level of CRMP2 was also affected by monocular deprivation in kitten. These experiments show that CRMPs underlie both normal development and plasticity-related adaptations of the cat visual cortex.