Distribution of the phosphorylated form of microtubule associated protein 1B in the fish visual system during optic nerve regeneration

Microtubule associated proteins are a heterogeneous group of proteins that have been implicated in regulating microtubule stability. They play an impo rtant role in the organisation of the neuronal cytoskeleton during neurite outgrowth, plasticity and regeneration. The fish visual system presents a c onsiderable degree of plasticity. Thus, the retina grows continually throug hout life and the optic nerve regenerates after crush. In the present study , we compared the distribution of the microtubule associated protein 1B in its phosphorylated form (MAP1B-phos) in the normal adult fish visual system with that observed during optic nerve regeneration after adult optic nerve crush using a specific monoclonal antibody mAb-150. Expression of MAP1B-ph os was observed in some ganglion cell somata and in developing, growing axo ns within the control optic nerve. Few immunoreactive terminals were seen i n the control optic tectum. After optic nerve crush, we found additional MA P1B-phos expression in regenerating axons throughout the visual system. Our results demonstrate that MAP1B-phos is present in growing and regenerating axons of fish retinal ganglion cells, which suggests that the phosphorylat ed form of MAP1B may play an important role in developmental and regenerati on processes within the fish central nervous system. (C) 2001 Elsevier Scie nce Inc.