Magang geese exhibit a unique characteristic of follicular development, with eight largest orderly arranged pre-ovulatory follicles in the abdominal cavity. However, little is known about the mechanisms underlying this follicular development. This study aimed to compare gene expression profiles of granulosa cells (GCs) at different stages of follicular development and provide comprehensive insights into follicle selection and the mechanisms underlying the well-defined follicle hierarchy in Magang geese. GCs of large white follicles (LWFs), small yellow follicles (SYFs), F8, F4, and F1 were used for RNA-seq analysis; 374, 1117, 791, and 593 genes were differentially expressed in stages LWFs to SYFs, SYFs to F8, F8 to F4, and F4 to F1, respectively, suggesting that these genes contribute to follicle selection and development. Reliability of sequencing data was verified through qPCR analysis of 24 genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways revealed a complex mechanism that remodels the extracellular matrix and turnover of extracellular matrix components in follicular development and ovulation and involves multiple pathway, such as focal adhesion, adherens junction, and extracellular matrix–receptor interaction. Some unique characteristics were observed during the different follicular development stages. For instance, some differentially expressed genes were enriched in progesterone-mediated oocyte maturation and steroid biosynthesis from stage SYFs to F8, whereas others were enriched in actin cytoskeleton regulation and vascular smooth muscle contraction from stage F4 to F1. These findings enhance our current understanding of GC function and ovarian follicles during the key stages of follicular development.

中文翻译：

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转录组分析揭示马岗鹅卵泡发育的基因表达谱

马岗鹅具有独特的卵泡发育特征，腹腔内有8个最大、有序排列的排卵前卵泡。然而，人们对这种卵泡发育的潜在机制知之甚少。本研究旨在比较不同卵泡发育阶段颗粒细胞 (GCs) 的基因表达谱，并全面了解马冈鹅卵泡的选择和明确的卵泡等级的潜在机制。大白卵泡 (LWF)、小黄卵泡 (SYF)、F8、F4 和 F1 的 GC 用于 RNA-seq 分析；374、1117、791 和 593 个基因分别在 LWFs 到 SYFs、SYFs 到 F8、F8 到 F4 和 F4 到 F1 阶段中差异表达，表明这些基因有助于卵泡的选择和发育。通过对 24 个基因的 qPCR 分析验证了测序数据的可靠性。Gene Ontology 和京都基因和基因组通路百科全书揭示了一种复杂的机制，该机制在卵泡发育和排卵过程中重塑细胞外基质和细胞外基质成分的周转，涉及多种途径，如粘着斑、粘附连接和细胞外基质 - 受体相互作用。在不同的卵泡发育阶段观察到一些独特的特征。例如，从 SYFs 到 F8 阶段，一些差异表达的基因富含孕酮介导的卵母细胞成熟和类固醇生物合成，而其他基因则富含肌动蛋白细胞骨架调节和从 F4 阶段到 F1 的血管平滑肌收缩。