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 first obtained from a mouse brain library  and is classified as part of the snoRNA family known as the H/ACA box class due to its predicted structure and conserved motifs. Its association with the GAR1 protein adds to our understanding of its role.