Antisense RNA ( aRNA ) is a single-stranded RNA that is complementary to messenger RNA ( mRNA).

The mRNA is transcribed from codogenic strand ( template strand ) of the DNA. If also the complementary strand is transcribed, produces a complementary to the mRNA aRNA. The aRNA inhibited by base pairing with the complementary mRNA whose translation in the cell. Thus, the gene expression of individual genes is regulated.

Antisense RNA provides a natural way of gene regulation of protein biosynthesis dar. In humans, there are at least 1,600 antisense genes, such as insulin -like growth factor 2 receptor ( IGF -2). In this gene, depending of genetic characteristics, a second promoter may be active at the 3 ' end of the gene is transcribed on the antisense RNA,. This prevents the translation of the sequence in both alleles of this gene. Thus, the phenotype does not follow the Mendelian genetics.

Is used antisense RNA, for example, in biotechnology, such as the commercially less successful Flavr Savr tomato. Here, an artificial gene is introduced into the tomato, the antisense - RNA to a gene involved in the maturing process produces the codes for the enzyme polygalacturonase. This allows the maturation process of the so-called Flavr Savr tomato be delayed. Another example is the potato Amflora, in which the technique was applied to suppress the production of potato amylose.

Besides its use in biotechnology, the system of anti- sense RNA is becoming increasingly widespread in medicine and pharmacology. The first drug based on antisense technology and has been approved for transport, is the antiviral drug fomivirsen against cytomegalovirus.

The molecular and cellular biology is used in vitro generated antisense RNA for in situ hybridizations.