Chapter 17, Problem 36P

Scientists have exploited the siRNA pathway to perform a technique called RNA interference—a means to knock down the expression of a specific gene without having to make mutations in it. The idea is to introduce dsRNA corresponding to the target gene into an organism; the dsRNA is then processed into an siRNA that leads to the degradation of the target gene’s mRNA. One clever method for delivery of the dsRNA to some organisms (the nematode C. elegans, for example) is to feed them bacteria transformed with a recombinant plasmid that expresses dsRNA.

a.	Draw a gene construct that, when expressed from a plasmid in bacteria, could be used to knock down by RNA interference the expression of gene X of C. elegans.
b.	How can you test if gene X expression is obliterated in worms that have eaten the bacteria transformed with a plasmid containing your construct?
c.	Do you think that only gene X expression will be affected in these worms? Explain.