Several experiments have shown leaky/deregulated expression of reporter genes viz., GUS from plant promoters in Agrobacterium cells. Which one of the following approaches would be most useful in restricting transgene expression in transformed plant cells and prevent their expression in Agrobacterium?
1
Use of weak promoters to express the transgene
2
Use of 5‟ and 3‟ UTRs flanking the transgene
3
Avoiding use of the polyA signal
4
Use of intron(s) within the transgene sequence