question_answer 44)

    Gene expression can be controlled with the help of RNA. Explain the method with an example.

Answer:

                    RNAi technology is used to block the expression of certain genes and also referred to asgene silencing. During this process, a complementary RNA to the mRNA being produced by the gene is introduced into the cell. This RNA binds to the mRNA making it double stranded and therefore, stops the process of translation. e.g., a nematode Meloidegyneincognitia infects the roots of tobacco plants which reduces the production of tobacco. It can be prevented by using RNA interference (RNAi) process which is checked by silencing of specific mRNA due to a complementary dsRNA. dsRNA binds and prevents the translation of mRNA (silencing). By using Agrobactenum vectors, Nematode-specific genes were introduced into the host plants which produces both sense and anti-sense RNA in the host cells. These two RNAs are complementary to each other and form a double-stranded RNA (dsRNA) that initiates RNAi and hence, silence the specific mRNA of the nematode. The parasite cannot survive in transgenic host and so prevents the plants from pests.