Intron-binding protein aquarius, Intron-binding protein of 160 kDa, IBP160, AQR, KIAA0560
AQR is intron-binding spliceosomal protein required to link pre-mRNA splicing and snoRNP (small nucleolar ribonucleoprotein) biogenesis. This protein plays a key role in position-dependent assembly of intron-encoded box C/D small snoRNP, splicing being required for snoRNP assembly. This protein may act by helping the folding of the snoRNA sequence. AQR binds to intron of pre-mRNAs in a sequence-independent manner, contacting the region between snoRNA and the branchpoint of introns (40 nucleotides upstream of the branchpoint) during the late stages of splicing.