Rather, U3 is thought to guide site-specific cleavage of ribosomal RNA (rRNA) during pre-rRNA processing.

[3] Both box B/C and C'/D motifs are involved in specific protein interactions and are necessary for the rRNA processing functions of U3 snoRNA.

Two potential mRNA binding motifs have been identified on U3 that base pair with the target sequences 5'-CUACCUCUCU-3' and 5'-CUCAGGAG-3'.

[4] S. cerevisiae secondary structure determined by chemical mapping of U3A RNA in a purified snoRNP is available.

[6] Like yeast and human, protozoan protist Entamoeba histolytica : a primitive eukaryote adopted the same conserved secondary structure of U3 snoRNA.