Mihm M, Baker P J, Fleming L M, Monteiro A M, O'Shaughnessy P J
Division of Cell Sciences, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK.
Reproduction. 2008 Feb;135(2):253-65. doi: 10.1530/REP-06-0193.
This study was designed to identify genes that regulate the transition from FSH- to LH-dependent development in the bovine dominant follicle (DF). Serial analysis of gene expression (SAGE) was used to compare the transcriptome of granulosa cells isolated from the most oestrogenic growing cohort follicle (COH), the newly selected DF and its largest subordinate follicle (SF) which is destined for atresia. Follicle diameter, follicular fluid oestradiol (E) and E:progesterone ratio confirmed follicle identity. Results show that there are 93 transcript species differentially expressed in DF granulosa cells, but only 8 of these encode proteins known to be involved in DF development. Most characterised transcripts upregulated in the DF are from tissue development genes that regulate cell differentiation, proliferation, apoptosis, signalling and tissue remodelling. Semiquantitative real-time PCR analysis confirmed seven genes with upregulated (P< or =0.05) mRNA expression in DF compared with both COH and SF granulosa cells. Thus, the new genes identified by SAGE and real-time PCR, which show enhanced mRNA expression in the DF, may regulate proliferation (cyclin D2; CCND2), prevention of apoptosis or DNA damage (growth arrest and DNA damage-inducible, beta; GADD45B), RNA synthesis (splicing factor, arginine/serine rich 9; SFRS9) and unknown processes associated with enhanced steroidogenesis (ovary-specific acidic protein; DQ004742) in granulosa cells of DF at the onset of LH-dependent development. Further studies are required to show whether the expression of identified genes is dysregulated when abnormalities occur during DF selection or subsequent development.
本研究旨在鉴定调控牛优势卵泡（DF）中从依赖促卵泡素（FSH）向依赖促黄体素（LH）发育转变的基因。采用基因表达系列分析（SAGE）比较从雌激素分泌最多的生长卵泡群（COH）、新选择的DF及其注定闭锁的最大从属卵泡（SF）中分离的颗粒细胞转录组。卵泡直径、卵泡液雌二醇（E）和E:孕酮比值确定了卵泡的身份。结果显示，DF颗粒细胞中有93种转录本差异表达，但其中只有8种编码已知参与DF发育的蛋白质。在DF中上调的大多数特征性转录本来自调控细胞分化、增殖、凋亡、信号传导和组织重塑的组织发育基因。半定量实时PCR分析证实，与COH和SF颗粒细胞相比，DF中有7个基因的mRNA表达上调（P≤0.05）。因此，通过SAGE和实时PCR鉴定的新基因在DF中显示出增强的mRNA表达，可能在LH依赖发育开始时调控颗粒细胞中的增殖（细胞周期蛋白D2；CCND2）、预防细胞凋亡或DNA损伤（生长停滞和DNA损伤诱导蛋白，β；GADD45B）、RNA合成（富含精氨酸/丝氨酸的剪接因子9；SFRS9）以及与增强类固醇生成相关的未知过程（卵巢特异性酸性蛋白；DQ004742）。需要进一步研究以表明在DF选择或后续发育过程中出现异常时，所鉴定基因的表达是否失调。
