Department of Animal Science, Center for Reproductive Biology and Health (CRBH), College of Agricultural Sciences, The Pennsylvania State University, University Park, Pennsylvania.
Transgenic Mouse Facility, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania.
Mol Reprod Dev. 2020 Jun;87(6):666-679. doi: 10.1002/mrd.23324. Epub 2020 Feb 3.
Preferentially expressed antigen in melanoma (PRAME) is cancer/testis antigen and a transcriptional repressor, inhibiting the signaling of retinoic acid through the retinoic acid receptor (RAR) for promoting cell proliferation and preventing cell apoptosis in cancer cells. The role of PRAME in testis and germline is unknown. We report here the generation and characterization of an X-linked Prame conditional knockout (cKO) mouse. Although fertile, the testis size (p < .01) and sperm count (p < .05) of the Prame cKO mice were significantly reduced by 12% at 4 months of age compared with the Prame floxed mice. Histological, immunofluorescence with germ cell-specific markers and terminal deoxynucleotidyl transferase dUTP nick end labeling analyses of testis cross-sections at postnatal day 7 (P7), P14, P21, P35, P120, and P365 indicated a significant increase in apoptotic germ cells at P7 and P14 and an increase in abnormal seminiferous tubules at P21 and P35. Germ cells were gradually lost resulting in two different phenotypes in the Prame cKO testes: Sertoli-cell-only for some of the affected tubules in young mice (at P35) and germ cell arrest at spermatogonia stage for other affected tubules in mature mice. Both phenotypes were a consequence of disruption in RAR signaling pathway by the depletion of Prame at a different time point during the first and subsequent rounds of spermatogenesis. The results suggest that Prame plays a minor, but important role in spermatogenesis and different paralogs in the Prame gene family may be functionally and partially redundant.
黑色素瘤优先表达抗原（PRAME）是一种癌/睾丸抗原和转录抑制剂，通过抑制维甲酸受体（RAR）的信号传导，促进癌细胞增殖并防止细胞凋亡。PRAME 在睾丸和生殖细胞中的作用尚不清楚。我们在此报告了 X 连锁 Prame 条件性敲除（cKO）小鼠的产生和特征。尽管具有生育能力，但与 Prame floxed 小鼠相比，Prame cKO 小鼠的睾丸大小（p<0.01）和精子计数（p<0.05）在 4 个月龄时分别降低了 12%。对生后第 7（P7）、14、21、35、120 和 365 天的睾丸横切片进行组织学、与生殖细胞特异性标志物的免疫荧光和末端脱氧核苷酸转移酶 dUTP 缺口末端标记分析表明，在 P7 和 P14 时凋亡的生殖细胞显著增加，在 P21 和 P35 时异常的曲细精管增加。生殖细胞逐渐丢失，导致 Prame cKO 睾丸出现两种不同的表型：在年轻小鼠（P35）中，一些受影响的曲细精管表现为支持细胞仅有的表型，而在成熟小鼠中，其他受影响的曲细精管表现为精原细胞停滞。这两种表型都是由于在第一次和随后的精子发生过程中，Prame 的缺失破坏了 RAR 信号通路的结果。结果表明，Prame 在精子发生中发挥次要但重要的作用，并且 Prame 基因家族中的不同同源基因可能具有功能上的冗余性。
