Enables H4K20me3 modified histone binding activity. Acts upstream of or within histone H4-K20 trimethylation; negative regulation of peptidyl-serine phosphorylation of STAT protein; and positive regulation of stem cell differentiation. Located in nucleus. Is expressed in several structures, including brain; neural retina; and trachea. Orthologous to human PWP1 (PWP1 homolog, endonuclein). [provided by Alliance of Genome Resources, Apr 2022]