Dual histone methylation reader specific for PRDM9-catalyzed histone marks (H3K4me3 and H3K36me3) that facilitates the repair of PRDM9-induced meiotic double-strand breaks (DSBs) (PubMed:32374261, PubMed:32352380, PubMed:32744506). Essential for male fertility and spermatogenesis (PubMed:31453335, PubMed:32374261, PubMed:32352380, PubMed:32744506). Required for meiosis prophase I progression in male but not in female germ cells (PubMed:31453335). Testis (at protein level) (PubMed:31453335, PubMed:32352380, PubMed:32374261, PubMed:32744506). Expressed in thymus, brain, lung, ovary, oviduct and uterus (PubMed:31453335). The CW-TYPE zinc finger mediates its binding to trimethylated histone H3K4me3. Male mice are sterile with complete azoospermia and reduced testis size, show impaired spermatogenesis, spermatocytes display meiotic arrest at around the zygotene to pachytene stage with incomplete homologous synapsis which is accompanied by defective DNA double-strand breaks repair (PubMed:31453335, PubMed:32374261, PubMed:32352380, PubMed:32744506). Fertility of females is normal up to mid-adulthood (5 to 6 months of age), at 3 and 6 months, ovaries exhibit healthy ovarian morphologies, however ovaries are devoid of follicles at around 8 months of age, and accordingly female mice become infertile (PubMed:31453335, PubMed:32744506). Female germ cells exhibit a successful but delayed meiosis prophase I progression (PubMed:31453335).