The article reports the discovery of a novel class of ribonucleoproteins (RNPs) called miRNPs, which contain numerous microRNAs (miRNAs). The study identifies Gemin3 and Gemin4 as components of a separate complex from the SMN complex, which also includes SMN, Gemin2, Gemin5, and Gemin6. This new complex, which contains eIF2C2, a member of the Argonaute protein family, forms a large ~15S RNP. The authors identify 40 miRNAs in this complex, some of which are novel and distinct from previously described human miRNAs. The genomic sequences suggest that these miRNAs likely derive from larger precursors capable of forming stem-loop structures. The miRNPs are characterized by their sedimentation on sucrose gradients and their association with Gemin3, Gemin4, and eIF2C2. The study also explores the interaction between these proteins and the potential regulatory roles of miRNAs. The findings provide insights into the function of miRNAs and their interactions with other proteins, particularly in the context of RNA interference and developmental regulation.The article reports the discovery of a novel class of ribonucleoproteins (RNPs) called miRNPs, which contain numerous microRNAs (miRNAs). The study identifies Gemin3 and Gemin4 as components of a separate complex from the SMN complex, which also includes SMN, Gemin2, Gemin5, and Gemin6. This new complex, which contains eIF2C2, a member of the Argonaute protein family, forms a large ~15S RNP. The authors identify 40 miRNAs in this complex, some of which are novel and distinct from previously described human miRNAs. The genomic sequences suggest that these miRNAs likely derive from larger precursors capable of forming stem-loop structures. The miRNPs are characterized by their sedimentation on sucrose gradients and their association with Gemin3, Gemin4, and eIF2C2. The study also explores the interaction between these proteins and the potential regulatory roles of miRNAs. The findings provide insights into the function of miRNAs and their interactions with other proteins, particularly in the context of RNA interference and developmental regulation.