{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nThe BPY2B gene product, also referred to as VCY2 in these studies, is a testis‐specific protein that localizes predominantly to the nuclei of germ cells including spermatogonia, spermatocytes, round spermatids, and even ejaculated spermatozoa. Its expression pattern in normal testicular tissue along with its marked reduction or absence in cases of maturation arrest or hypospermatogenesis underscores its likely pivotal role in germ cell development and the regulation of spermatogenesis, with impaired expression being associated with male infertility."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "Furthermore, BPY2B/VCY2 has been shown to interact directly with ubiquitin-protein ligase E3A (UBE3A). Using yeast two-hybrid screening complemented by co-immunoprecipitation studies, researchers demonstrated that UBE3A binds to a specific domain of the BPY2B/VCY2 protein, suggesting that ubiquitination may be necessary for its proper function during spermatogenesis—an observation further supported by the co-expression of both mRNAs in ejaculated spermatozoa."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "Collectively, these findings indicate that BPY2B/VCY2 plays a critical regulatory role in male germ cell development possibly through mechanisms involving nuclear localization and post-translational modification by ubiquitination, thereby contributing to normal spermatogenesis and male fertility."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "J Y M Tse, E Y M Wong, A N Y Cheung, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Specific expression of VCY2 in human male germ cells and its involvement in the pathogenesis of male infertility."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biol Reprod (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1095/biolreprod.103.015792"}], "href": "https://doi.org/10.1095/biolreprod.103.015792"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12724276"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12724276"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Elaine Y M Wong, Jenny Y M Tse, Kwok-Ming Yao, et al. "}, {"type": "b", "children": [{"type": "t", "text": "VCY2 protein interacts with the HECT domain of ubiquitin-protein ligase E3A."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochem Biophys Res Commun (2002)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/s0006-291x(02)02040-5"}], "href": "https://doi.org/10.1016/s0006-291x(02"}, {"type": "t", "text": "02040-5) PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12207887"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12207887"}]}]}]}