MicroRNAs (miRNAs) are small, highly conserved non-coding RNA molecules that play a crucial role in gene expression regulation. They are transcribed by RNA polymerases II and III, undergoing a series of cleavage events to form mature miRNAs. The conventional biogenesis pathway involves two cleavage events, one nuclear and one cytoplasmic, but alternative pathways exist. The sorting of miRNA precursors to different pathways is determined by their origin, sequence, and thermodynamic stability. MiRNAs function through the RNA-induced silencing complex (RISC), where they target messenger RNAs (mRNAs) for degradation or translation inhibition. The degree and nature of complementarity between the miRNA and target mRNA determine the silencing mechanism. Recent evidence suggests that P-bodies are essential for miRNA-mediated gene silencing, with RISC assembly and silencing occurring primarily within these compartments. The P-body model outlines the sorting and shuttling of miRNAs between specialized compartments within P-bodies, addressing the reversibility of silencing mechanisms. Understanding the pathways of miRNA biogenesis and function is essential for comprehending their physiological roles and implications in diseases such as cancer.MicroRNAs (miRNAs) are small, highly conserved non-coding RNA molecules that play a crucial role in gene expression regulation. They are transcribed by RNA polymerases II and III, undergoing a series of cleavage events to form mature miRNAs. The conventional biogenesis pathway involves two cleavage events, one nuclear and one cytoplasmic, but alternative pathways exist. The sorting of miRNA precursors to different pathways is determined by their origin, sequence, and thermodynamic stability. MiRNAs function through the RNA-induced silencing complex (RISC), where they target messenger RNAs (mRNAs) for degradation or translation inhibition. The degree and nature of complementarity between the miRNA and target mRNA determine the silencing mechanism. Recent evidence suggests that P-bodies are essential for miRNA-mediated gene silencing, with RISC assembly and silencing occurring primarily within these compartments. The P-body model outlines the sorting and shuttling of miRNAs between specialized compartments within P-bodies, addressing the reversibility of silencing mechanisms. Understanding the pathways of miRNA biogenesis and function is essential for comprehending their physiological roles and implications in diseases such as cancer.