Problem
Recent studies have shown that when exposed to *N. nemesis*, corn can produce and export a miRNA that targets the fungal gene *FCOA*. In fungi such as *N. nemesis*, the *FCOA* gene codes for a transcriptional co-activator. Like many co-activators, FCOA is a protein that assists transcription factors in binding to DNA.
The miRNA produced by corn in response to *N. nemesis* is exported from the corn and then taken up by *N. nemesis*. This miRNA is completely complementary to a highly conserved region of the *FCOA* coding sequence.
Even though the miRNA is highly specific to the mRNA of the *FCOA* gene, researchers found that when *N. nemesis* was exposed to this miRNA expression of a number of other genes in the fungus were down-regulated. Explain how expression of genes other than *FCOA* could be down-regulated.