ACA57 was originally cloned from a mouse brain library  and belongs to the H/ACA box class of snoRNAs as it has the predicted hairpin-hinge-hairpin-tail structure, has the conserved H/ACA-box motifs and is found associated with GAR1 protein.
ACA57 was initially derived from a mouse brain library  and belongs to the group of small nucleolar RNAs (snoRNAs) known as the H/ACA box class due to its predicted structure and conserved motifs. It is also linked to the GAR1 protein.