Enhanced detection of tRNA isoacceptors by combinatorial oligonucleotide hybridization

A method that greatly enhances the detection of tRNA by oligodeoxyribonucle otide probe hybridization has been developed. Because highly structured tRN A regions often preclude heteroduplex formation, we have tested the ability of cold oligodeoxyribonucleotides called unfolders to disrupt the tRNA sec ondary/tertiary structures and promote hybridization of a second labeled ol igonucleotide complementary to the anticodon loop. Here we show that an exc ess of unfolders in the pre/hybridization reaction can enhance a barely det ectable hybridization signal by more than 200-fold without affecting probe specificity. This sensitive assay makes it possible to easily study and mon itor changes in tRNA isoacceptor expression.