Activity of sialidases in fetal brain axonal growth cones and during postnatal development.
In the present work the cytosolic, membrane-bound and the total activities of brain sialidases were measured in fetal axonal growth cone particles and in various brain regions during brain development. The developmental profile showed an important activity in the prenatal and perinatal periods as well as in specific differentiating structures like the axonal growth cones from the fetal brain. Interestingly membrane-bound activity was higher than the cytosolic activity, starting from 50-60% at birth and increasing thereafter. Cytosolic activity was almost at adult levels at birth and did not show a further significant increase thereafter. Our results strongly suggest the commitment of membrane-bound sialidase activity in early neurodifferentiating phenomena like axogenesis, probably regulating the turnover of glycoconjugates like gangliosides at the presynaptic period, since high activity was observed in neuroblast's derived membranes and in the perinatal period.
Hernandez-R
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J
Department of Physiology, Biophysics and Neurosciences, Centro de Investigacion y de Estudios Avanzados del IPN, Universidad Autonoma de Queretaro, Mexico. jorgeh@fisio.cinvestav.mx
Boyzo
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Mercadoc
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D000818:Animals; D001369:Axons / Q000201:enzymology* / Q000648:ultrastructure; D001921:Brain / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development / Q000648:ultrastructure; D001923:Brain Chemistry; D002531:Cerebellum / Q000196:embryology / Q000201:enzymology / Q000254:growth & development / Q000648:ultrastructure; D003600:Cytosol / Q000201:enzymology; D005326:Fetal Proteins / Q000032:analysis*; D006001:Glycoconjugates / Q000378:metabolism; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009439:Neuraminidase / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar
D005326:Fetal Proteins; D006001:Glycoconjugates; D009419:Nerve Tissue Proteins; D009439:Neuraminidase