RNA interference (RNAi) is a key mechanism for regulating gene expression in eukaryotic cells, involving small non-coding RNAs such as miRNAs and siRNAs. These RNAs associate with Argonaute proteins to form RISC complexes, which guide sequence-specific silencing of complementary mRNAs through endonucleolytic cleavage or translational repression. The miRNA pathway involves the processing of pri-miRNAs by the microprocessor complex (Drosha and DGCR8) and subsequent cleavage by Dicer to generate mature miRNAs. The siRNA pathway similarly involves Dicer processing of dsRNA precursors. Both pathways converge on the RISC loading complex, which includes Dicer, Argonaute, and a dsRNA-binding protein. The structure and function of these proteins are critical for the efficiency and specificity of RNAi. The Argonaute family proteins, including Ago1-4 in humans, are essential for RISC function, with Ago2 exhibiting slicer activity. The interaction between Argonaute and other proteins, such as dsRBPs and GW proteins, is crucial for RISC assembly and silencing. The C3PO endonuclease promotes passenger strand dissociation and RISC activation. The study of RNAi mechanisms has advanced significantly, providing insights into the molecular structures and interactions that govern RNA silencing. These findings are essential for understanding the role of RNAi in gene regulation and for developing RNAi-based therapies.RNA interference (RNAi) is a key mechanism for regulating gene expression in eukaryotic cells, involving small non-coding RNAs such as miRNAs and siRNAs. These RNAs associate with Argonaute proteins to form RISC complexes, which guide sequence-specific silencing of complementary mRNAs through endonucleolytic cleavage or translational repression. The miRNA pathway involves the processing of pri-miRNAs by the microprocessor complex (Drosha and DGCR8) and subsequent cleavage by Dicer to generate mature miRNAs. The siRNA pathway similarly involves Dicer processing of dsRNA precursors. Both pathways converge on the RISC loading complex, which includes Dicer, Argonaute, and a dsRNA-binding protein. The structure and function of these proteins are critical for the efficiency and specificity of RNAi. The Argonaute family proteins, including Ago1-4 in humans, are essential for RISC function, with Ago2 exhibiting slicer activity. The interaction between Argonaute and other proteins, such as dsRBPs and GW proteins, is crucial for RISC assembly and silencing. The C3PO endonuclease promotes passenger strand dissociation and RISC activation. The study of RNAi mechanisms has advanced significantly, providing insights into the molecular structures and interactions that govern RNA silencing. These findings are essential for understanding the role of RNAi in gene regulation and for developing RNAi-based therapies.