Component of the ribosomal small subunit processome for the biogenesis of ribosomes, functions in pre-ribosomal RNA (pre-rRNA) processing (PubMed:28263972). Essential for embryonic development in part through the regulation of p53 pathway. Required for the expansion growth of intestine, liver and exocrine pancreas, but not endocrine pancreas. May not play a major role during the early stage of endodermal organogenesis. Also involved in the sympathetic neuronal development (PubMed:28263972). Triggers the degradation of p53/TP53 and Delta113p53 isoform in a ubiquitination pathway independent way (PubMed:23357851). Mediates, with CAPN3, the proteasome-independent degradation of p53/TP53 (PubMed:23357851, PubMed:27657329). Mainly expressed in digestive organs at the later stage of organogenesis. Expressed in liver, gut and exocrine pancreas, but not in the islets. Highly expressed in the embryos at 12 hpf and 1 dpf and expressed at high level at 3 dpf and 4 dpf, but at a lower level at 5 dpf. At 2 dpf, ubiquitously expressed, but enriched in the mid and hindbrain boundary. Through 3-5 dpf, expressed mainly in the gut, liver, pancreas and pharynx. Phosphorylated. Phosphorylation is required to facilitate the nucleolar localzsation of CAPN3 and promote p53/TP53 degradation in the nucleolus which promotes cell cycle progression and liver development. Confers hypoplastic digestive organs and selectively up-regulates the expression of the Delta113p53 isoform but not p53, resulting in compromised organ growth in def mutant fish. Loss of function affects sympathetic neuronal development (PubMed:27657329). Belongs to the UTP25 family.