Wang Chieh-Ying, Tang Ming-Chu, Chang Wen-Chi, Furushima Kenryo, Jang Chuan-Wei, Behringer Richard R, Chen Chun-Ming
Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.
Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan Laboratory Animal Center, National Yang-Ming University, Taipei, Taiwan.
Biol Reprod. 2016 Sep;95(3):51. doi: 10.1095/biolreprod.116.141739. Epub 2016 Jul 27.
Bobby sox homolog (Bbx) is an evolutionally conserved gene, but its biological function remains elusive. Here, we characterized defects of Bbx mutant rats that were created by PiggyBac-mediated insertional mutagenesis. Smaller body size and male infertility were the two major phenotypes of homozygous Bbx mutants. Bbx expression profile analysis showed that Bbx was more highly expressed in the testis and pituitary gland than in other organs. Histology and hormonal gene expression analysis of control and Bbx-null pituitary glands showed that loss of Bbx appeared to be dispensable for pituitary histogenesis and the expression of major hormones. BBX was localized in the nuclei of postmeiotic spermatids and Sertoli cells in wild-type testes, but absent in mutant testes. An increased presence of aberrant multinuclear giant cells and apoptotic cells was observed in mutant seminiferous tubules. TUNEL-positive cells costained with CREM (round spermatid marker), but not PLZF (spermatogonia marker), gammaH2Ax (meiotic spermatocyte marker), or GATA4 (Sertoli cell marker). Finally, there were drastically reduced numbers and motility of epididymal sperm from Bbx-null rats. These results suggest that loss of BBX induces apoptosis of postmeiotic spermatids and results in spermiogenesis defects and infertility.
短袜同源蛋白（Bbx）是一个进化上保守的基因，但其生物学功能仍不清楚。在此，我们对通过PiggyBac介导的插入诱变产生的Bbx突变大鼠的缺陷进行了表征。体型较小和雄性不育是纯合Bbx突变体的两个主要表型。Bbx表达谱分析表明，Bbx在睾丸和垂体中的表达高于其他器官。对照和Bbx基因敲除垂体的组织学和激素基因表达分析表明，Bbx的缺失似乎对垂体组织发生和主要激素的表达是可有可无的。BBX定位于野生型睾丸减数分裂后精子细胞和支持细胞的细胞核中，但在突变睾丸中不存在。在突变的生精小管中观察到异常多核巨细胞和凋亡细胞的数量增加。TUNEL阳性细胞与CREM（圆形精子细胞标记物）共染色，但不与PLZF（精原细胞标记物）、γH2Ax（减数分裂精子细胞标记物）或GATA4（支持细胞标记物）共染色。最后，Bbx基因敲除大鼠附睾精子的数量和活力大幅降低。这些结果表明，BBX的缺失诱导减数分裂后精子细胞的凋亡，并导致精子发生缺陷和不育。
