Use of antisense RNA to help identify a genomic clone for the 5' region of mouse beta-glucuronidase

Towards Gene-Inhibition Therapy: A Review of Progress and Prospects in the Field of Antiviral Antisense Nucleic Acids and Ribozymes

Antisense RNA and its derivatives may provide the basis for highly selective gene inhibition therapies of virus infections. In this review, I concentrate on advances made in the study of antisense RNA and ribozymes during the last five years and their implications for the development of such therapies. It appears that antisense RNAs synthesized at realistic levels within the cell can be much more effective inhibitors than originally supposed. Looking at those experiments that enable comparisons to be made, it seems that inhibitory antisense RNAs are not those that are complementary to particular sites within mRNAs but those that are able to make stable duplexes with their targets, perhaps by virtue of their secondary structure and length. The inclusion of ribozyme sequences within antisense RNAs confers RNA-cleaving activity upon them in vitro and possibly in cells, thereby offering the possibility of markedly increasing their therapeutic potential. The varieties of natural ribozyme and their adaptation as artificial catalysts are reviewed. The implications of these developments for antiviral therapy are discussed.

Antisense transgenics in animals

Antisense transgenesis provides a methodology for ablating gene expression in targeted tissues through the use of tissue-specific or controllable promoters. The two major features to be considered in the design of a construct for injection are (1) the target sequence and (2) the promoter to be used. Information is provided to help the investigator make decisions in these regards. The standard methodology of making transgenics is not replicated but some hints as how best to use a transgenic facility are provided. An overview of methods for studying transgene expression and target gene suppression is given. In summary, antisense transgenesis may provide a more readily achievable method for tissue-specific ablation of a gene's function than controllable knockouts provide.

Antisense inhibition of beta-glucuronidase expression in preimplantation mouse embryos: a comparison of transgenes and oligodeoxynucleotides

Using as a model the inhibition of beta-glucuronidase expression in preimplantation embryos, we have compared injections of transgenes directing the synthesis of antisense RNA and antisense oligodeoxynucleotides to our previous results with cytoplasmic injections of antisense RNAs. Pronuclear injection of an antisense DNA construct containing 1.4 kb of coding region of beta-glucuronidase fused to the mouse metallothionein I promoter results in transient inhibition of gene expression in preimplantation mouse embryos. Pronuclear injection of a smaller antisense DNA construct, overlapping the start codon, failed to inhibit gene expression. Injection of two 20-mer antisense oligodeoxynucleotides, one complementary to sequences including the initiation codon and the second complementary to exon 7 sequences of the beta-glucuronidase gene, failed to inhibit gene expression. In addition, cultures of embryos in the presence of antisense oligodeoxynucleotides had no effect on gene activity. Using radiolabeled oligomers added to the culture medium, we found poor uptake of oligodeoxynucleotides by embryos.