Inhibition of huntingtin synthesis by antisense oligodeoxynucleotides

The Huntington disease gene encodes the protein huntingtin, which is widely expressed during embryonic development and in mature tissues. In order to elucidate the physiological function of huntingtin, which so far is unknown , we intend to study the effect of antisense downregulated huntingtin expre ssion. We have found an inhibiting effect of a phosphorothioated oligodeoxy nucleotide (PS-ODN) added to the culture medium of embryonic teratocarcinom a cells (NT2) and postmitotic neurons (NT2N neurons) differentiated from th e NT2 cells. Specific inhibition of expression of endogenous huntingtin was achieved in NT2N neurons in the concentration range of 1-5 muM PS-ODN, whe reas no inhibition was obtained in NT2 cells. We describe in detail the sel ection of the target sequence for the antisense oligo and the uptake, intra cellular distribution, and stability of the antisense PS-ODN in the two cel l types. Antisense down-regulation of huntingtin in this model of human neu rons represents a suitable approach to study its normal function.