A neuron-specific isoform of brain ankyrin, 440-kD ankyrinB, is targeted to the axons of rat cerebellar neurons.
Two isoforms of brain ankyrin, 440- and 220- kD ankyrinB, are generated from the same gene by alternative splicing of pre-mRNA. The larger isoform shares the same NH2-terminal and COOH-terminal domains to the smaller isoform and contains, in addition, a unique inserted domain of about 220-kD in size (Kunimoto, M., E. Otto, and V. Bennett. 1991. J. Cell Biol. 115:1319-1331). Both Isoforms were expressed in primary cerebellar cells in a manner similar to that in vivo; the larger isoform appeared first when axogenesis is actively conducted and the smaller isoform came up later. 440-kD ankyrinB was localized in the axons of cerebellar neurons both in vivo and in vitro using an antibody raised against the insert region, while 220-kD isoform was rather localized in the cell bodies and dendrites of neurons by a specific antibody prepared using a synthetic peptide corresponding to the splice site as antigen. Astroglia cells also expressed 220-kD ankyrinB but not the 440-kD isoform. These results indicate that 440-kD ankyrinB is a neuron-specific isoform targeted to the axons and its unique inserted domain is essential for the targeting.
Kunimoto
M
M
Environmental Health Sciences Division, National Institute for Environmental Studies, Ibaraki, Japan.
D000818:Animals; D000831:Animals, Newborn; D017487:Ankyrins / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D000918:Antibody Specificity; D001369:Axons / Q000737:chemistry* / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured / Q000737:chemistry; D002531:Cerebellum / Q000166:cytology; D007150:Immunohistochemistry; D007536:Isomerism; D008970:Molecular Weight; D009474:Neurons / Q000737:chemistry* / Q000648:ultrastructure; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar
D017487:Ankyrins