The National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.
Molecular Biology Division, Faculty of Pharmaceutical Sciences, Nagasaki International University, Nagasaki, Japan.
Genes Cells. 2021 Mar;26(3):180-189. doi: 10.1111/gtc.12832.
TRA98 is a rat monoclonal antibody (mAb) which recognizes a specific antigen in the nuclei of germ cells. mAb TRA98 has been used to understand the mechanism of germ cell development and differentiation in many studies. In mice, the antigen recognized by mAb TRA98 or GCNA1 has been reported to be a GCNA gene product, but despite the demonstration of the immunoreactivity of this mAb in human testis and sperm in 1997, the antigen in humans remains unknown, as of date. To identify the human antigen recognized by mAb TRA98, a human comprehensive wet protein array was developed containing 19,446 proteins derived from human cDNAs. Using this array, it was found that the antigen of mAb TRA98 is not a GCNA gene product, but nuclear factor-κB activating protein (NKAP). In mice, mAb TRA98 recognized both the GCNA gene product and NKAP. Furthermore, conditional knockout of Nkap in mice revealed a phenotype of Sertoli cell-only syndrome. Although NKAP is a ubiquitously expressed protein, NKAP recognized by mAb TRA98 in mouse testis was SUMOylated. These results suggest that NKAP undergoes modifications, such as SUMOylation in the testis, and plays an important role in spermatogenesis.
TRA98 是一种识别生殖细胞核内特定抗原的大鼠单克隆抗体 (mAb)。mAb TRA98 已被用于许多研究中，以了解生殖细胞发育和分化的机制。在小鼠中，mAb TRA98 或 GCNA1 识别的抗原已被报道为 GCNA 基因产物，但尽管 1997 年已经证明该 mAb 在人类睾丸和精子中具有免疫反应性，但截至目前，人类的抗原仍然未知。为了鉴定 mAb TRA98 识别的人类抗原，开发了一种包含 19446 个人 cDNA 衍生蛋白的人类综合湿蛋白阵列。使用该阵列，发现 mAb TRA98 的抗原不是 GCNA 基因产物，而是核因子-κB 激活蛋白 (NKAP)。在小鼠中，mAb TRA98 既识别 GCNA 基因产物，也识别 NKAP。此外，在小鼠中条件性敲除 Nkap 揭示了 Sertoli 细胞综合征的表型。虽然 NKAP 是一种广泛表达的蛋白质，但在小鼠睾丸中由 mAb TRA98 识别的 NKAP 是 SUMOylated 的。这些结果表明，NKAP 在睾丸中经历修饰，如 SUMOylation，并在精子发生中发挥重要作用。
