Plays a role in the maintenance of the appropriate processing of 47S/45S pre-rRNA to 32S/30S pre-rRNAs and their subsequent processing to produce 18S and 28S rRNAs (By similarity). Also acts at the level of transcription regulation. Along with PRMT5, binds embryonic globin promoter (By similarity). Represses the expression of embryonic globin Hbb-y gene (PubMed:25092918). In neuroblastoma cells, may also repress the expression of oxidative stress genes, including CHAC1, HMOX1, SLC7A11, ULBP1 and that encoding the small nucleolar RNA SNORD41 (By similarity). Preferentially binds to a DNA motif containing 5'-GGTTAT-3' (By similarity). Negatively regulates the antiviral innate immune response by targeting IRF3 and impairing its DNA-binding activity (By similarity). In addition, inhibits NF-kappa-B-mediated expression of pro-inflammatory cytokines (By similarity). Stimulates phagocytosis of photoreceptor outer segments by retinal pigment epithelial cells (PubMed:25735755). Prevents NCL self-cleavage, maintaining a normal steady-state level of NCL protein in undifferentiated embryonic stem cells (ESCs), which in turn is essential for ESC self-renewal (PubMed:19489080). Interacts with PRMT5; this interaction is direct (By similarity). Interacts with GNL2 and RPL23A (By similarity). Interacts with nucleolin/NCL; this interaction is direct (PubMed:19489080, PubMed:23212345). Interacts with phosphorylated IRF3; this interaction impairs IRF3 DNA-binding activity (By similarity). Component of pre-ribosomal particles, including pre-40S, pre-60S and pre-90S (By similarity). Associated with cytoplasmic ribosomes, but not polysomes, as a component of the 60S subunit (PubMed:24990247). In the retina, predominantly expressed in photoreceptor outer segments (PubMed:25735755). In the nucleolus, colocalizes with nucleolin/NCL, therefore may reside in the dense fibrillar component (DFC) (PubMed:19489080). Predominantly expressed in testis, in germ cells, and at a moderate level in spleen, liver and lung (at protein level) (PubMed:19489080, PubMed:23212345, PubMed:24990247). Very high levels in spermatogonia, spermatocytes and round spermatids, but not in testicular sperm and mature sperm (at protein level) (PubMed:20339383, PubMed:23212345, PubMed:24990247). Expressed in ovary (PubMed:20339383). Expressed in the retina, including in photoreceptor outer segments (at protein level) (PubMed:25735755). Expressed in undifferentiated embryonic stem cells (PubMed:19489080, PubMed:23212345). Expressed in testis and ovary at 15.5 dpc (PubMed:20339383). May be differentially expressed during spermatogenesis. Detected first at P12, the early stage of spermatogenesis. Levels considerably increase at P16, corresponding to the development of pachytene spermatocytes (PubMed:23212345). The N-terminal zinc-finger domains are required for the appropriate production of 28S rRNA and the formation of pre-60S particles. No visible phenotype. Mutant mice are fully fertile and show intact spermatogenesis.