Conversion of embryonic to adult form of the neural cell adhesion molecule (N-CAM) does not correlate with pre- and postmigratory states of mouse cerebellar granule neurons.
The migration of postmitotic granule neurons from the external to the internal granular layer along the radial processes of Bergmann glia is an outstanding event in the development of the early postnatal mouse cerebellar cortex. It has been hypothesized that the conversion of the embryonic to the adult form of the neural cell adhesion molecule (N-CAM) is important for this migration since this conversion coincides with the time of migration [2, 10]. To investigate this issue we have examined the molecular forms of N-CAM by Western blot analysis in tissue obtained from hand-dissected cerebellar layers at several stages of early postnatal development. Here we report that there is no temporal difference between internal and external granular layers in shifting from exclusive expression of the embryonic form of N-CAM at postnatal day 1 to predominance of the adult form at day 17. White matter shows a delay in the conversion to the adult form which is completed only after day 17. We conclude that the transition from embryonic to adult form of N-CAM is not a prerequisite for granule neuron migration.
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis*; D015815:Cell Adhesion Molecules; D002465:Cell Movement; D002525:Cerebellar Cortex / Q000166:cytology; D002531:Cerebellum / Q000032:analysis / Q000196:embryology / Q000254:growth & development*; D051379:Mice; D008810:Mice, Inbred C57BL; D008938:Mitosis; D009024:Morphogenesis
D000954:Antigens, Surface; D015815:Cell Adhesion Molecules