S1_Rrp5_repeat_hs5: Rrp5 is a trans-acting factor important for biogenesis of both the 40S and 60S eukaryotic ribosomal subunits. Rrp5 has two distinct regions, an N-terminal region containing tandemly repeated S1 RNA-binding domains (12 S1 repeats in Saccharomyces cerevisiae Rrp5 and 14 S1 repeats in Homo sapiens Rrp5) and a C-terminal region containing tetratricopeptide repeat (TPR) motifs thought to be involved in protein-protein interactions. Mutational studies have shown that each region represents a specific functional domain. Deletions within the S1-containing region inhibit pre-rRNA processing at either site A3 or A2, whereas deletions within the TPR region confer an inability to support cleavage of A0-A2. This CD includes H. sapiens S1 repeat 5 (hs5) and S. cerevisiae S1 repeat 5 (sc5). Rrp5 is found in eukaryotes but not in prokaryotes or archaea.