1. The Flavr Savr Tomato

2. Flavr Savr Tomato The first FDA approved genetically modified food
Licensed in 1994
Ripening causes production of an enzyme Polygalacturonase in a gradual increasing level, which is responsible for softening of the tomato and which becomes the cause of rottening
Calgene introduced a gene in plant which synthesize a complementary mRNA to PG gene and inhibiting the synthesis of PG enzyme.

3. Antisense RNA
Antisense RNA (asRNA) is a single-stranded RNA that is complementary to a messenger RNA (mRNA) strand transcribed within a cell.

4. Put PG gene sequences in the reverse orientation into the vector
Transformation
Isolate the nuclei used for in vitro transcription
Isolate the RNA
Hybridize RNA
Measure PG activity
Lycopene determination

5. Result

6. PG gene suppression is the result of RNAi

7. Promoter antisense cDNA poly A addition signal
antisense oligonucleotide
mRNA
-antisense
RNA complex
dsRNA
Binding of dsRNA-specific nuclease
cleavage
mRNA is cleaved!
Nuclease-ssRNA complex
Hybridizes to mRNA
sense
antisense

8. Southern blot Two linked T-DNAs
Left T-DNA, lanes 1 and 2 (primers 1 and 4);
Right T-DNA, lanes 3 and 4 (primers 2 and 3); full insert, lanes 5 and 6 (primers 1 and 2); unique junction region, lanes 7 and 8 (primers 5 and 6).
Diagram of the sequenced 13,621-bp T-DNA insertion and flanking genomic regions. DNA probes (bars C and D) and primers (arrows 1–6) used for confirmation PCRs are indicated.

9. Northern blot

10. Result Flavr Savr locus contains two linked T-DNAs
siRNAs from transgenes accumulate in Flavr Savr tomatoes.