Gene Silencing via RNA Interference in Cryptococcus

RNA interference (RNAi) is a molecular biology technique for silencing specific eukaryotic genes without altering the DNA sequence in the genome. The silencing effect occurs because of decreased levels of mRNA that then result in decreased protein levels for the gene. The specificity of the silencing is dependent upon the presence of sequence-specific double-stranded RNA (dsRNA) that activates the cellular RNAi machinery. This chapter describes the process of silencing a specific target gene in Cryptococcus using a dual promoter vector. The plasmid, pIBB103, was designed with two convergent GAL7 promoters flanking a ura5 fragment that acts as a reporter for efficient RNAi. The target gene fragment is inserted between the promoters to be transcribed from both directions leading to the production of dsRNA in cells that activate the RNAi pathway.