摘要
A large variety of eukaryotic small structured POLIII-derived non-coding RNAs(ncRNAs)have been described in the past.However,for only few,e.g.7SL and H1/MRP families,cellular functions are well understood.For the vast majority of these transcripts,cellular functions remain unknown.Recent findings on the role ofY RNAs and other POLIII-derived ncRNAs suggest an evolutionarily conserved function of these ncRNAs in the assembly and function of ribonucleoprotein complexes(RNPs).These RNPs provide cellular‘machineries’,which are essential for guiding the fate and function of a variety of RNAs.In this review,we summarize current knowledge on the role of POLIII-derived ncRNAs in the assembly and function of RNPs.We propose that these ncRNAs serve as scaffolding factors that‘chaperone’RNA-binding proteins(RBPs)to form functional RNPs.In addition or associated with this role,some small ncRNAs act as molecular decoys impairing the RBP-guided control of RNA fate by competing with other RNA substrates.This suggests that POLIII-derived ncRNAs serve essential and conserved roles in the assembly of larger RNPs and thus the control of gene expression by indirectly guiding the fate of mRNAs and IncRNAs.
