The emerging landscape of small nucleolar RNAs in cell biology.
Bottom Line: As a family, they have been well characterized as playing a central role in ribosome biogenesis, guiding either the sequence-specific chemical modification of pre-rRNA (ribosomal RNA) or its processing.In recent years, thanks in great part to advances in sequencing methodologies, we have seen many examples of the diversity that exists in the snoRNA family on multiple levels.Under the deluge of novel features and functions that have recently come to light, snoRNAs emerge as a central, dynamic, and highly versatile group of small regulatory RNAs.
Affiliation: Biochemistry Department, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Canada.Show MeSH
Mentions: Typical box C/D snoRNAs (Figure 1(a)) are between 60 and 90 nucleotides in length and are characterized by the presence of conserved boxes C (consensus sequence RUGAUGA) and D (consensus sequence CUGA) near their 5′ and 3′ termini, respectively.2,19,20 The boxes C and D align and fold into a kink-turn (k-turn) motif involving noncanonical G–A base pairing resulting in a sharp bend in the axis of the double-stranded RNA molecule.3,21 The box C/D k-turn is essential for biogenesis and proper localization, serving as a binding site for core box C/D snoRNP proteins.3,19,21,22 Additional motifs, the boxes C′ and D′, with the same consensus sequences as the boxes C and D, respectively, but typically less well conserved and often degenerate, are found toward the middle of the molecule2,20 (Figure 1(a)). The guide regions with complementarity to the targets are located immediately upstream from the boxes D′ and/or D, the modified residues always base pairing with the fifth residue upstream from these motifs.3,19,20,17
Affiliation: Biochemistry Department, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Canada.