Enables chromatin binding activity and histone binding activity. Involved in DNA demethylation of male pronucleus and positive regulation of DNA demethylation. Acts upstream of or within C-5 methylation of cytosine. Located in cytoplasm; germinal vesicle; and pronucleus. Orthologous to human STPG4 (sperm-tail PG-rich repeat containing 4). [provided by Alliance of Genome Resources, Apr 2022]