Cattleyak, which are interspecific hybrids between cattle and yak, display much higher growth performances than yak. However, F1 male cattleyak are infertile due to defective testicular development. Sirtuin 1 (SIRT1) is a histone deacetylase that is essential for various biological processes, while the roles of testicular SIRT1 in yak and cattleyak are still poorly understood. Here, we found that SIRT1 was localized in various kinds of yak testicular cells except elongated spermatids while it was deficient in cattleyak testis. Further studies indicated that cattleyak testis exhibited decreased histone acetylation levels on H3 and H4. One of SIRT1 co‐factors, steroidogenic factor‐1 (SF‐1), was lost in cattleyak testis at protein level. Expressions of several SF‐1 target genes responsible for Sertoli cell development and steroidogenesis, including STAR, CYP11A1, CYP26B1, FDX1 and HSD3B, decreased significantly in cattleyak testis. In addition, SIRT1‐mediated P53 acetylation was not responsible for the cell apoptosis in cattleyak testis. Taken together, our results suggested the deficiency of SIRT1 in yak testis caused inactivation of SF‐1 and the impairment of testicular development. This research provides theoretical bases for understanding the mechanism of cattleyak sterility and gives new insights in revealing the roles of SIRT1 in regulating yak testicular development.

中文翻译：

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Sirtuin 1的缺乏通过使SF-1失活来损害牛y的睾丸发育。

Cattleyak是牛和ak牛之间的种间杂种，表现出比牛高得多的生长性能。但是，由于睾丸发育不良，F1雄性y牛不育。Sirtuin 1（SIRT1）是一种组蛋白脱乙酰基酶，对于各种生物学过程至关重要，而对睾丸SIRT1在牛和牛中的作用仍知之甚少。在这里，我们发现SIRT1定位于除了细长的精子细胞之外的各种牛睾丸细胞中，而它在牛y睾丸中却缺乏。进一步的研究表明，cattle皮睾丸在H3和H4上的组蛋白乙酰化水平降低。SIRT1辅助因子之一类固醇生成因子-1（SF-1）在蛋白质含量的牛test睾丸中丢失。负责支持细胞发育和类固醇生成的几种SF-1目标基因的表达，包括牛y睾丸中的STAR，CYP11A1，CYP26B1，FDX1和HSD3B显着降低。此外，SIRT1介导的P53乙酰化与cattle牛睾丸中的细胞凋亡无关。综上所述，我们的结果表明is牛睾丸中SIRT1的缺乏会导致SF-1失活和睾丸发育受损。该研究为了解牛y的不育机理提供了理论基础，并为揭示SIRT1在调节牛睾丸发育中的作用提供了新的见解。