Homo sapiens C/D box snoRNA U106. This snoRNA was first cloned from a rat cDNA library, and its human orthologue identified by database search (Vitali et al., 2003). Upstream of the D and D' boxes, it contains two conserved, 9-10 nt long, antisense elements matching two 18S rRNA segments. However, the two predicted targets (18S rRNA G1536 and U1602) do not appear to be methylated. U106, the highly related snoRNA SNORD12B (Yang et al., 2006) and HBII-99 (SNORD12) share the same host gene (C20orf199), and have probably the same target (28S rRNA G3878). Consequently, the HGNC approved symbol for U106 was changed from SNORD106 to SNORD12C.