1) Antisense is the non-coding DNA strand of a gene. A cell uses antisense DNA strand as a template for producing messenger RNA (mRNA) that directs the synthesis of a protein. Antisense can also refer to a method for silencing genes. To silence a target gene, a second gene is introduced that produces an mRNA complementary to that produced from the target gene. These two mRNAs can interact to form a double-stranded structure that cannot be used to direct protein synthesis.

2) Nucleic acid that has a sequence exactly opposite to an mRNA molecule made by the body; binds to the mRNA molecule to prevent a protein from being made.