Homo sapiens C/D box snoRNA U101. This snoRNA was identified by Vitali et al. (2003) in the systematic search for C/D box hallmarks in the introns of ribosomal protein genes. U101 gene resides in intron 3 of the ribosomal protein S12 gene, whereas intron 4 of the same gene hosts the C/D box snoRNA HBII-429, and intron 5 the H/ACA box snoRNA ACA33. U101 has no predicted target RNA.