Antisence Technology

Antisense Technology:

—  The  general concept for  antisense  technology  was created in the mid of 19^th century(1978).

—  Scientist coined the term “Antisense” because the mRNA sequence is known as the “sense” sequence. Since this technology blocks the mRNA it became known as “Antisense”.

      In principle, antisense technology is supposed to prevent protein production from a targeted gene.

Antisense oligonucleotides:

—  Antisense  oligonucleotides are single strands of DNA  or RNA that are complimentary to the chosen sequence.

—  In the case of antisense RNA they prevent protein translation of certain messenger RNA strands by binding to them.

—  Antisense DNA can be used to target a specific, complimentary(coding or  non coding) RNA.

—  If binding takes places this DNA/RNA hybrid can be degraded by the enzyme RNase H.

A case study in antisense technology;

The Flavr Savr Tomato:

Tomatoes allowed to completely ripen on the vine develop their full color, flavor and softness characteristics in great demand by consumers. But for shipping purposes, commercially grown tomatoes must be picked before they get too soft, resulting in hard, bland-tasting tomatoes at the market. The agricultural biotechnology company Calgene (California) used antisense technology to inhibit the production of the fruit-softening enzyme polygalacturonase which breaks down a cell wall polysaccharide. This resulted in a 90% reduction in polygalacturonase activity and a significantly longer ripening period. The “Flavr Savr” tomatoes could be left on the vine longer  to develop  color and flavor without getting as soft as normal tomatoes.  But they could still be shipped without being damaged and they would eventually soften at the market or at home. But, the Flavr Savr tomato  was only produced commercially for a few  years because the variety  used for genetic engineering  had inferior agronomic characteristics (too small, low yield). DNA Plant Technologies later introduced an antisense engineered tomato (“Endless Summer”) which inhibited ethylene production, but withdrew the product after a patent fight with Monsanto and take-over by another company.