The secondary structure of a 678-nt 5' fragment of mRNA of the human multip
le drug resistance (MDR) gene mdr1 was analyzed in order to identify optima
l targets for antisense oligonucleotides. The data of RNA structure probing
with RNases ONE, T1, and V1 and computer simulation suggested a three-doma
in structure of the region under study. The accessible sites thus predicted
efficiently hybridized with complementary oligonucleotides.