GEL SHIFT ASSAY - DEMONSTRATION OF ENHANCED BINDING OF OLIGO(DELTA)-L-ORNITHINE-OLIGODEOXYNUCLEOTID CONJUGATES TO COMPLEMENTARY-DNA AND RNA

An increase in melting temperature for DNA:DNA duplexes had been obser ved previously (Zhu et al. Antisense Res, Dev, 3:349-356, 1993) when a n oligo(delta)ornithine moiety was covalently appended to a short olig odeoxynucleotide. We now report the analysis of duplex formation by el ectrophoretic gel shift analysis, In the particular example studied, a n increase in T-m of 4 degrees C was found to correspond to about a fi vefold increase in binding constant. A similar enhancement by the appe nded cationic peptide was observed when the target strand was RNA, The use of a competitive assay format for avoidance of adsorptive loss at low concentrations (<10(-7) M) of the oligonucleotide-oligo(delta)orn ithine conjugate is presented.