Small ribonucleoproteins in ribosome biogenesis

Abstract

Small nucleolar RNPs (snoRNPs) are abundant macromolecular assemblies in the nucleolus of eukaryotic cells and are essential for the synthesis of functional ribosomes. Generally, they use their RNA components as guides to determine their site of function by means of base-pairing between guide RNA and substrate RNA. SnoRNPs have both enzymatic and non-enzymatic functions. As enzymes, they catalyze nucleotide modifications and endonucleolytic cleavages of RNA substrates. When they are not acting as enzymes, they can be scaffolds for the assembly of even larger macromolecules, for example, the SSU processome/90S preribosome, or play a role in RNA folding as chaperones. In this chapter, we review our current understanding of the function and structure of small RNPs in the nucleolus. © 2011 Springer Science+Business Media, LLC.