The present invention provides methods for designing a sequence for efficient short interference RNA molecules. In particular, the present invention defines a universal target for siRNA derived from a poly A sequence, optionally in conjunction with unique sequences for gene silencing and inhibition of viral replication in a eukaryotic host cell. The present invention further provides methods for the treatment and prevention of diseases and disorders by silencing a gene of a virus, an oncogene, genes encoding transcription factors and many other diseases related genes. The present invention describes antisense nucleic acids compositions comprising sequences complementary to a target nucleic acid. The antisense sequences are designed to hybridize to complementary nucleic acid target regions in a target RNA, and inhibit translation, processing, transport, or binding by proteins or riboproteins. Target regions include, and are limited to a poly-A tail, and exclude, AUG, 5 non-translated sequences, translation initiation factor binding sites, ribosome subunit binding sites, Shine Dalgarno sequence, 3 nontranslated sequences, poly- addition site, 3 cleavage site, coding region, intron, intron branch site, intron/exon junction, and splice sequence.Linvention concerne un procédé de conception dune séquence permettant lobtention de molécules efficaces de petits ARN interférents (siARN). En particulier, linvention définit une cible universelle pour le siARN dérivé dune séquence poly A, optionnellement en association à des séquences uniques pour le silençage de gènes et linhibition de la réplication virale dans une cellule hôte eukariote. Linvention concerne en outre des procédés de traitement et de prévention de maladies et de troubles, par silençage dun gène dun virus, dun ocogène, dun gène codant des facteurs de transcription et de nombreux autres gènes associés à des maladies. Linvention concerne en outre des compositions dacides nucléiques anti-sens comprenant des séquenc
