Antisense RNA

Antisense RNA is the transcription product of the DNA sense strand--the strand that does not encode a protein. It is complementary to mRNA and may be able to pair with an mRNA molecule, thereby inhibiting its translation. Antisense RNA has been shown to control the expression of several prokaryotic and eukaryotic genes. Systems regulated by antisense include the following:

> ompC/ompF Genes - The ompC and ompF genes encode outer membrane proteins in E. coli. The antisense RNA regulating this system is the product of the micf gene, which is partly complementary to sequences in the 5' end of ompF mRNA. The micf RNA inactivates the ompF message, presumably by forming a duplex RNA in vivo. The translational initiation signal of OmpF mRNA, which must be single-stranded to direct translation, is included in this duplex and is probably blocked for translation initiation.

> CRP - crp is the structural gene for the cAMP Receptor Protein

> Tn10 - Transposon Tn10 uses an antisense mechanism to regulate the level of its transposase.

See also: Transposable Genetic Elements (from Chapter 25)

INTERNET LINK: Antisense RNA