Antisense oligonucleotides: Modulation of gene expression with modified oligos

Traditional antisense oligonucleotides (ASO)-based gene modulation (usually synonymous with silencing or downregulation of gene expression, but it can be used to improve gene expression and, in at least one particular case, it was shown to lead to upregulation of gene expression) targets mRNA and can take place in either the nucleus or the cytoplasm. Gene silencing should be simple, but there are many considerations to take into account for a successful ASO design. In this application note, Merck presents ASOs for modulation of gene expression. The note highlights common types of ASO modification and provides considerations for different types of experiments.