Purpose

The age-associated decline in female fertility is largely ascribable to the decrease in oocyte quality. The subcortical maternal complex (SCMC) is a multiprotein complex essential for early embryogenesis and female fertility and functionally conserved across mammals. The present work evaluated expression dynamics of its components during folliculogenesis in relation to maternal age in sheep.

Methods

The expression of the SCMC components (KHDC3/FILIA, NLRP2, NLRP5/MATER, OOEP/FLOPED, PADI6, TLE6 and ZBED3) was analyzed by real-time PCR in pools of growing oocytes (GO) of different diameters (70–90 μm (S), 90–110 μm (M), or 110–130 μm (L)) derived from non-hormonally treated adult (Ad; age < 4 years), prepubertal (Pr; age 40 days), or aged ewes (age > 6 years).

Results

Specific expression patterns associated with donor age were observed during folliculogenesis for all genes, except ZBED3. In oocytes of adult donors, the synthesis of NLRP2, NLRP5, PADI6, and ZBED3 mRNAs was complete in S GO, while FILIA, TLE6, and OOEP were actively transcribed at this stage. Conversely, Pr GO showed active transcription of all mRNAs, except for ZBED3, during the entire window of oocyte growth. Notably, aged GO showed a completely inverse pattern, with a decrease of NLRP2, TLE6, FILIA, and PADI6 mRNA abundance during the latest stage of oocyte growth (L GO). Interestingly, MATER showed high expression variability, suggesting large inter-oocyte differences.

Conclusion

Our study describes the SCMC expression dynamics during sheep oogenesis and reports age-specific patterns that are likely involved in the age-related decline of oocyte quality.

中文翻译：

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卵泡发生过程中皮质下母体复合物（SCMC）的表达受绵羊卵母细胞供体年龄的影响。

目的

与年龄相关的女性生育能力下降很大程度上归因于卵母细胞质量的下降。皮层下母体复合物 (SCMC) 是一种多蛋白复合物，对早期胚胎发生和雌性生育能力至关重要，并且在哺乳动物中功能保守。目前的工作评估了与绵羊母体年龄相关的卵泡发生过程中其成分的表达动态。

方法

SCMC 组分（KHDC3/FILIA、NLRP2、NLRP5/MATER、OOEP/FLOPED、PADI6、TLE6和ZBED3）的表达通过实时 PCR 在不同直径（70-90 μm）的生长卵母细胞 (GO) 池中进行分析(S)、90–110 μm (M) 或 110–130 μm (L)）来自未经激素处理的成年（Ad；年龄 < 4 岁）、青春期前（Pr；年龄 40 天）或老年母羊（年龄 > 6 岁）。

结果

除ZBED3外，所有基因在卵泡发生过程中均观察到与供体年龄相关的特定表达模式。在成年供体的卵母细胞中，NLRP2、NLRP5、PADI6和ZBED3 mRNA的合成在S GO中完成，而FILIA、TLE6和OOEP在此阶段转录活跃。相反，在卵母细胞生长的整个窗口期间，Pr GO 显示出除ZBED3之外的所有 mRNA 的活跃转录。值得注意的是，老年 GO 表现出完全相反的模式，NLRP2、TLE6、FILIA和PADI6 下降卵母细胞生长的最新阶段 (L GO) 的 mRNA 丰度。有趣的是，MATER表现出高表达变异性，表明卵母细胞间存在较大差异。

结论

我们的研究描述了绵羊卵子发生过程中的 SCMC 表达动态，并报告了可能与年龄相关的卵母细胞质量下降有关的特定年龄模式。