The inhibition of neurite outgrowth in PC12 cells by tubulin antisense oligodeoxyribonucleotides.

A model system was designed to determine the effect of antisense oligodeoxyribonucleotides (oligos) on the expression of endogenous tubulin genes, the major component of microtubules, and to study the involvement of individual tubulin isoforms in specific functions, by employing antisense oligos which can block the expression of specific transcripts, both in vitro and in vivo. In reticulocyte cell-free system, specific inhibition of mRNA translation was observed with oligos complementary to the 5' alpha-tubulin-coding region. In vivo inhibition of neurite outgrowth was observed in nerve growth factor-induced PC12 cells. Specific inhibition was observed in cells treated with antisense oligos corresponding to the 5' alpha-tubulin-coding region as well as with antisense oligos corresponding to the 3' alpha-noncoding regions of two different alpha-tubulin isoforms. The results show that both tubulin isoforms are involved in neurite outgrowth and further demonstrate the ability of oligos to block expression of endogenous genes and thus follow the involvement of those gene products in cellular differentiation.