Facts Endopolygalacturonase of tomato was suspected of having a prominent role in the softening of tomato fruit during ripening. In vitro, a DNA fragment corresponding to part of the endopolygalacturonase gene was inserted next to a transcription promoter in the orientation opposite to the normal orientation. Such cRNAs are known as antisense RNAs. The constructed antisense gene was used to transform tomato using Agrobacteria . The antisense strategy is an alternative to the knock-out strategy, particularly in organisms in which homologous recombination is difficult to achieve.
Antisense transgenes are usually dominant in their effects.
If the location of the gene on the molecular map is known, the antisense strategy may associate a genetically scorable phenotype with that map position, thus tying the two types of maps together. Antisense strategies should work with multigene families provided the members are sufficiently closely related. The dsRNA appears to induce RNA degradation mechanisms that can last through many cell generations. The phenomenon may be another version of co-suppression . The target sequences are not always available for binding by the antisense molecule.