Question

why isn't single stranded rna or dna as effective in anti sense targeting? Why is single stranded rna or dna so hard to use in comparison to dsRNA for anti sense targeting?

Answer 1

The main problem with single stranded RNA or DNA is to stabilize the RNA strand against degradation by nucleases. In various studies, potential of ss-siRNA in transcriptional regulation has been evaluated and found to have good potential in regulation like double stranded one. Bout such ss-siRNAs arechemically modified of its nucleotides to prevent degradation.

There is no such problem with Double stranded RNA or DNA in antisense targeting. For example, Dicer cleaves long double stranded RNA into short single stranded RNA which readily incorporates into RISC complex. RISC with a bound siRNA recognizes complementary messenger RNA (mRNA) and thus regulates it.