## Description

This track displays positions of four different types of RNA in the human genome:

- microRNAs from the miRNA Registry at the Wellcome Trust Sanger Institute
- small nucleolar RNAs (C/D box and H/ACA box snoRNAs) and Cajal body-specific RNAs (scaRNAs) from the snoRNABase maintained at the Laboratoire de Biologie Moléculaire Eucaryote

C/D box and H/ACA box snoRNAs are guides for the 2'O-ribose methylation and the pseudouridilation, respectively, of rRNAs and snRNAs, although many of them have no documented target RNA. The scaRNAs guide modifications of the spliceosomal snRNAs transcribed by RNA polymerase II, and often contain both C/D and H/ACA domains.

## Display Conventions and Configuration

This track follows the general display conventions for gene prediction tracks.

The miRNA precursor forms (pre-miRNA) are represented by red blocks.

C/D box snoRNAs, H/ACA box snoRNAs and scaRNAs are represented by blue, green and magenta blocks, respectively. At a zoomed-in resolution, arrows superimposed on the blocks indicate the sense orientation of the snoRNAs.

## Methods

Mature and precursor miRNAs from the miRNA Registry were aligned against the genome using blat. The extents of the precursor sequences were not generally known and were predicted based on base-paired hairpin structure. The miRNA Registry is described in Griffiths-Jones, S. (2004) and Weber, M.J. (2005) in the References section below.

The snoRNAs and scaRNAs from the snoRNABase were aligned against the human genome using blat.

## Credits

The miRNA annotation was contributed by Michel Weber of Laboratoire de Biologie Moléculaire Eucaryote, CNRS Université Paul Sabatier (UMR5099, Toulouse, France) and Sam Griffiths-Jones of The Wellcome Trust Sanger Institute (Cambridge, UK).

The snoRNA annotations were contributed by Michel Weber and Laurent Lestrade of the Institut d'Exploration Fonctionnelle des Génomes (IFR109, Toulouse, France).

Fan Hsu from the UCSC Genome Bioinformatics Group created the combined annotation track.

## References

When making use of these data, please cite:

Griffiths-Jones S. The microRNA Registry. Nucl. Acids Res. 2004 Jan 1;32(D):D109-11.

Weber MJ. New human and mouse microRNA genes found by homology search. Febs J. 2005 Jan;272(1):59-73.

You may also want to cite The Wellcome Trust Sanger Institute miRNA Registry and The Laboratoire de Biologie Moleculaire Eucaryote snoRNA database.

The following publication provides guidelines on miRNA annotation: Ambros V. et al., A uniform system for microRNA annotation. RNA. 2003;9(3):277-9.

For more information on blat, see Kent WJ. BLAT - the BLAST-like alignment tool. Genome Res. 2002;12(4):656-664.