Probing the function of novel genes in the nervous system: is antisense the answer?

Abstract

Antisense oligodeoxynucleotides (ODNs) have been used extensively to decrease or prevent the synthesis of target proteins. In theory, the technique is simple yet elegant: the complement of a target sequence of messenger ribonucleic acid (mRNA) encoding the protein of interest is used to disrupt translation or prevent translation initiation. However, in practice, the technique can be challenging and requires extensive controls. This chapter presents a unique experience with the design and use of an antisense ODN to alter the expression of serotonin-2A receptors in vitro and in vivo and discusses the mechanisms of action of antisense ODNs, potential nonantisense effects these ODNs may have, the design and testing of control and antisense ODNs in vitro, and the administration of an antisense ODN intracerebroventricularly to alter expression of a targeted protein in the brain. Antisense strategies have progressed rapidly. The established efficacy and specificity of this approach in animal models have resulted in the evaluation of antisense oligonucleotides in clinical trials for the treatment of cancer, Crohn's disease, human immunodeficiency virus (HIV) infection, and rheumatoid arthritis. Although the method can be technically challenging, the resulting data may yield information about the function of a protein that may otherwise be available only from gene knockout animals. Furthermore, antisense strategies allow researchers to knock down, transiently and inducibly, the expression of a protein, in many cases in a particular organ system or in a specific brain region, without the complications of interpreting data limited by the developmental compensation or lethality common in knockout animals.