Forkhead boxO (FOXO) transcription factors regulate diverse biological processes, including cellular metabolism, cell apoptosis, and the cell cycle. Results from several studies indicate FOXO1 regulates different granulosa cell (GC) pathways involved in proliferation, survival and differentiation. Functions and mechanisms of FOXO1 regulation of sheep GCs remain unclear. This study was conducted to analyze the function of FOXO1 in regulation of sheep GCs. In this study, the 1827 bp sheep FOXO1 coding sequence was cloned from sheep GCs. Multiple sequence alignment and phylogenetic analysis indicated that the FOXO1 protein sequence is highly homologous to FOXO1 protein sequences from other species. The results obtained from using CCK-8 assays indicated sheep GC proliferation increased when there was suppression of FOXO1 gene expression. When there was induced expression of the FOXO1 gene in sheep GCs, there was a resulting increased abundance of P21 and P27 mRNA transcript, whereas suppression of the FOXO1 gene expression had the opposite effect. Furthermore, the relative abundance in vitro of apoptosis-related protein mRNA transcripts (caspase3, caspase8, caspase9, Bax/Bcl-2) was markedly increased or decreased when there was induction or suppression of FOXO1 gene expression, respectively,(P < 0.05). Induction of FOXO1 gene expression resulted in an increase in abundance of steroidogenic protein mRNA transcripts (CYP11A1, 3β-HSD), while suppression of FOXO1 gene expresion resulted in a decrease abundance of the CYP11A1, STAR mRNA transcripts. Results from the present study indicated that FOXO1 inhibited the proliferation of sheep GCs and affected mRNA transcript abundance for proteins involved in regulation of apoptosis, the cell cycle and steroidogenesis.

Forkhead boxO (FOXO) 转录因子调节多种生物过程，包括细胞代谢、细胞凋亡和细胞周期。几项研究的结果表明 FOXO1 调节涉及增殖、存活和分化的不同颗粒细胞 (GC) 途径。FOXO1 调控绵羊 GC 的功能和机制尚不清楚。本研究旨在分析 FOXO1 在调节绵羊 GC 中的功能。在本研究中，1827 bp 的绵羊FOXO1编码序列是从绵羊 GC 中克隆的。多序列比对和系统发育分析表明 FOXO1 蛋白序列与来自其他物种的 FOXO1 蛋白序列高度同源。使用 CCK-8 测定获得的结果表明，当 FOXO1 基因表达受到抑制时，绵羊 GC 增殖增加。当在绵羊 GC 中诱导 FOXO1 基因表达时，导致P21和P27 mRNA 转录物的丰度增加，而 FOXO1 基因表达的抑制具有相反的效果。此外，凋亡相关蛋白 mRNA 转录物（caspase3、caspase8、caspase9、Bax/Bcl-2）的体外相对丰度)分别在诱导或抑制 FOXO1 基因表达时显着增加或减少，( P  < 0.05)。FOXO1 基因表达的诱导导致类固醇生成蛋白 mRNA 转录本（CYP11A1、3β-HSD）的丰度增加，而 FOXO1 基因表达的抑制导致CYP11A1、STAR mRNA 转录本的丰度降低。本研究的结果表明，FOXO1 抑制绵羊 GC 的增殖，并影响参与调节细胞凋亡、细胞周期和类固醇生成的蛋白质的 mRNA 转录丰度。