{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T04:48:33Z","timestamp":1785905313040,"version":"3.56.0"},"reference-count":48,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T00:00:00Z","timestamp":1785456000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Fundamental Research Funds for the Central Universities","award":["SWU-KT26026"],"award-info":[{"award-number":["SWU-KT26026"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomolecules"],"abstract":"<jats:p>Heterochromatin Protein 1\u03b3, encoded by the Cbx3 gene, is a crucial epigenetic regulator that plays an essential role in mammalian meiotic progression. However, the functional divergence and conservation of this protein in teleosts\u2014organisms possessing duplicated Cbx3 paralogs due to whole-genome duplication\u2014remain to be elucidated. Building on previous research, we focused on cbx3a in Nile tilapia (Oreochromis niloticus), a significant aquaculture species and an excellent model for teleost reproductive studies, emphasizing its role in spermatogenesis. Expression analysis revealed that Cbx3a is localized to primordial germ cells and is sustained in spermatogonia, spermatocytes, and spermatids during spermatogenesis. CRISPR\/Cas9-mediated knockout of cbx3a demonstrated that Cbx3a deficiency induces germ cell apoptosis, meiotic arrest, and sperm defects, including shortened tails and impaired motility, resulting in profound defects in sperm quantity and quality, strongly implying compromised male fertility. Transcriptomic analysis further identified dysregulated molecular pathways, including cytokine signaling and neuroactive ligand\u2013receptor interactions. This provides novel mechanistic insights into HP1\u03b3-mediated epigenetic regulation of meiosis. Notably, cbx3a mutants exhibited phenotypic bifurcation: a subset showed meiotic defects accompanied by sporadic germ cell apoptosis, whereas others underwent full meiotic arrest with pervasive germ cell apoptosis in adult gonads. Collectively, these findings clarify the essential and conserved role of Cbx3a\/HP1\u03b3 in Nile tilapia spermatogenesis, thereby advancing the field of vertebrate reproductive epigenetics and providing a valuable theoretical basis for potential applications in reproductive management, such as improving sperm quality.<\/jats:p>","DOI":"10.3390\/biom16081120","type":"journal-article","created":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T15:02:01Z","timestamp":1785510121000},"page":"1120","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Cbx3a\/HP1\u03b3 Deficiency Disrupts Meiotic Progression and Triggers Germ Cell Apoptosis in Nile Tilapia"],"prefix":"10.3390","volume":"16","author":[{"given":"Hongqin","family":"Jian","sequence":"first","affiliation":[{"name":"Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Chongqing Municipality for Aquatic Economic Animal Resources Conservation and Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiahong","family":"Wu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Chongqing Municipality for Aquatic Economic Animal Resources Conservation and Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruijuan","family":"Feng","sequence":"additional","affiliation":[{"name":"Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Chongqing Municipality for Aquatic Economic Animal Resources Conservation and Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liang","family":"Zhang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Chongqing Municipality for Aquatic Economic Animal Resources Conservation and Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Zhou","sequence":"additional","affiliation":[{"name":"Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Chongqing Municipality for Aquatic Economic Animal Resources Conservation and Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0507-6525","authenticated-orcid":false,"given":"Xingyong","family":"Liu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Chongqing Municipality for Aquatic Economic Animal Resources Conservation and Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"570","DOI":"10.1093\/biolre\/ioab085","article-title":"Epigenetic transgenerational inheritance, gametogenesis and germline development?","volume":"105","author":"Nilsson","year":"2021","journal-title":"Biol. 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