Expression and distribution of microtubule proteins in neurites of dorsal root ganglion neurons in culture

Abstract

The expression and distribution of β-tubulin gene products and post-translationally modified forms of α-tubulin in dorsal root ganglion neurons in culture were examined. The neurons in culture rapidly regenerated neurites and expressed multiple β-tubulin genes (Mβ2, Mβ3/4, Mβ5, Mβ6). The gene products were present in the neurites and growth cones. Unmodified tyrosinated α-tubulin was present in the neurites and growth cones but modified α-tubulins (detyrosinated and acetylated) were largely absent from growth cones. The distribution of the α-tubulin forms is consistent with assembly of tubulin occurring behind the growth cone after transport of non-polymeric subunits. Distal assembly of microtubules would provide a pool of unmodified α-tubulin subunits for the assembly of labile microtubules in the growth cone. Subsequent modification behind the advancing growth cone would stabilise the newly formed neurite.