Utilization of antisense oligodeoxynucleotides with embryonic tissues in culture

Experimental embryology has long used manipulation of interacting tissues to examine questions of tissue interaction and differentiation. The potential for specific manipulation of gene expression in such tissues has made the utilization of antisense techniques desirable. However, problems with this methodology have discouraged many investigators from using this approach. Selection of target sequences for antisense oligonucleotides, delivery of oligonucleotides into cells or tissues, and the type of modification of the oligonucleotide to be used all present concerns that must be addressed. This paper describes our approach to selection of target sequence and methods of delivery and describes the synthesis of a methoxyethylamidate-modified antisense oligonucleotide that has proved useful in our studies. This approach has enabled us to explore aspects of tissue interaction in the embryonic heart that would have been difficult to explore in a genetic model.