Mammalian Oocyte Regulation

RNA interference (RNAi) is an evolutionary conserved gene-silencing pathway that can be efficiently utilized as a tool to study gene function. RNAi is initiated by long double-stranded RNAs (dsRNAs), which are processed into small duplexes called small-interfering RNAs (siRNAs). In turn, these duplexes target mRNAs for degradation in a sequence-specific manner. Mouse oocytes, unlike most mammalian cell types, lack an interferon response to long dsRNA. Moreover, they are a rare example of a mammalian cell type with a robust endogenous RNAi pathway. For these reasons microinjection of either long dsRNAs or siRNAs results in efficient, sequence-specific gene silencing. Here, we describe a protocol for preparation and microinjection of long dsRNA into mouse oocytes.