Tudor domain-containing protein involved in germ cell development, more specifically the formation of chromatoid body (during spermiogenesis), Balbiani body (during oogenesis), germ plasm (upon fertilization), and for proper miRNA expression and spliceosome maturation (By similarity). Essential for RNA-dependent helicase UPF1 localization to chromatoid body, for UPF1-UPF2 and UPF1-DDX4 interactions which are required for mRNA degradation, using the extended 3' UTR-triggered nonsense-mediated mRNA decay (NMD) pathway. Involved in spliceosome maturation and mRNA splicing in prophase I spermatocytes through interaction with arginine N-methyltransferase PRMT5 and symmetrically arginine dimethylated SNRPB (small nuclear ribonucleoprotein-associated protein) (By similarity). Found in a mRNP complex (i.e. messenger ribonucleoproteins which correspond to mRNA with bound proteins), at least composed of TDRD1, TDRD6, TDRD7 and DDX4. Found in a complex, at least composed of PIWIL1, PIWIL2, DDX4 and TDRD6. Interacts with Tex19.1 and probably Tex19.2. Interacts with PRMT5. Interacts with SNRPB (when methylated); to trigger spliceosome formation. Present in chromatoid body (CB) of spermatids, also named processing bodies (P-bodies) in somatic cells. Detected in the multilobular cytoplasmic CBs (also called intermitochondrial cementin) in pachytene spermatocytes and as a single perinuclear CB in haploid round spermatids. Colocalizes in CB with DDX4, PIWIL1, PIWIL2, TDRD1 and TDRD7. The tudor domains recognize and bind to proteins with dimethylated arginine residues. Undergoes proteolytic cleavage near the C-terminal by an unknown protease during the transition from meiosis I to meiosis II in primary spermatocytes. Truncated N-terminus.