Heterogeneous expression of neurofilament proteins in forebrain and cerebellum during development: clinical implications for spinocerebellar ataxia.
Using quantitative immunoblotting, we have measured the level of two mammalian neurofilament proteins, the 68-kDa NF-L and the 66-kDa NF-66 (alpha-internexin), in the rat CNS during development. NF-66 is localized in neurons and neuronal processes in both embryonic and postnatal brain. Importantly, NF-66 is more abundant than NF-L in both forebrain and cerebellum during development. The prevalence of NF-66 over NF-L is most pronounced in brain gray matter. The expression of both NF-66 and NF-L increases continuously during the first month after birth. In situ hybridization demonstrated that NF-66, but not NF-L is, expressed in the cerebellar granule cells. Our findings suggest that the neurofilaments are heterogeneous in developmental expression, among neuronal subtypes and in composition. Human NF-66 neurofilament has recently been mapped to chromosome 10q24. Careful analysis of the human genome map indicates NF-66 gene lies within the critical region of infantile-onset spinocerebellar ataxia (IOSCA). The characteristic developmental expression and spatial localization of the NF-66 gene suggests it as a candidate gene for the disease.
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Saul Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Peng
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Chiu
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D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D015152:Blotting, Northern; D002524:Cerebellar Ataxia / Q000503:physiopathology*; D002531:Cerebellum / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D004622:Embryo, Mammalian / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D016900:Neurofilament Proteins / Q000096:biosynthesis*; D009474:Neurons / Q000378:metabolism; D016548:Prosencephalon / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley
D016900:Neurofilament Proteins; D012333:RNA, Messenger