Acts as both a transcriptional activator and repressor (PubMed:29866902, PubMed:29848638). Binds to the DNA sequence 5'-ACAAT-3' and shows a preference for guanine residues surrounding this core motif (PubMed:29866902). Binds to its own promoter and activates its own transcription (PubMed:29866902, PubMed:29848638). Required to activate the expression of postmeiotic genes involved in spermiogenesis (PubMed:29866902, PubMed:29848638). Binds to the promoter region of CTNNB1 and represses its transcription which leads to inhibition of Wnt signaling (PubMed:29739711). Also inhibits Wnt signaling by binding to the CTNNB1 protein, preventing interaction of CTNNB1 with TCF7L2/TCF4 (By similarity). Interacts with CTNNB1, competitively inhibiting CTNNB1-TCF7L2/TCF4 interaction. Enriched at the chromocenter. Expressed in the lung (at protein level) (PubMed:29739711). Expressed in testes (at protein level) (PubMed:10359848, PubMed:29848638, PubMed:25609838). Expressed in preleptotene spermatocytes, round spermatids, and elongated spermatids in the testis (at protein level) (PubMed:29866902, PubMed:25609838). Expressed in pachytene spermatocytes during stages 3 to 8 of spermatogenesis (at protein level) (PubMed:29866902, PubMed:29848638, PubMed:25609838). Increased expression in diplotene spermatocytes at stage 9-11 and in metaphase spermatocytes or secondary spermatocytes at stage 12 (PubMed:29848638, PubMed:25609838). Expressed in ovaries (PubMed:29848638). Expressed in the testes at 13.5 dpc (PubMed:10359848, PubMed:29848638). Also expressed in the mesonephros, metanephros, brain, lung, heart and stomach at 13.5 dpc (PubMed:10359848). Expressed in the testes at 14.5 dpc (PubMed:29848638). Expressed in the ovary at 13.5 and 14.5 dpc (PubMed:29848638). Expressed weakly in the testes at postnatal day 14 (P14), strongly expressed from P21 onwards (PubMed:29866902). Expressed in the nucleus of pachytene spermatocytes in stages 5 to 6 of spermatogenesis (PubMed:29866902). Expressed in round spermatids and increased expression in pachytene spermatocytes in stages 7 to 8 of spermatogenesis (PubMed:29866902). Expressed in the nucleus of diplotene spermatocytes in stages 11 to 12 of spermatogenesis, however expression in the nuclei of spermatids is lost (PubMed:29866902). Induced in germline stem cells by retinoic acid. Knockout mice are viable, morphologically normal, but males are sterile (PubMed:29866902, PubMed:29848638). Male mice exhibit small testes and epididymis (PubMed:29848638). Multinuclear syncytia present in the seminiferous tubules, with degenerated multi-chromocenter round spermatids and multinucleated giant cells in the epididymis lumen (PubMed:29848638). Increased numbers of apoptotic cells in the testes and epididymis (PubMed:29848638). Increased expression of CTNNB1, MYC, CCND1, and MMP7 in lung cells (PubMed:29739711). Increase in diplotene spermatocytes in the testes, indicative of defects in the later stages of meiosis (PubMed:29866902). Developmental failure of the large nuclear docking acrosome to develop during the cap phase of spermiogenesis (PubMed:29866902, PubMed:29848638). In addition disruption of proacrosomic vesicle translocation during spermatid differentiation results in the absence of elongating spermatids and therefore viable sperm (PubMed:29866902). No effect on transcription or processing of piRNA precursors (PubMed:29866902).