Pumilio3 (Pum3), an evolutionarily distant homologue of the classical RNA-binding protein PUF (PUMILIO and FBF) family member, is also involved in the process of RNA metabolism through post-transcriptional regulation. However, the functions of Pum3 in mouse oocyte maturation and preimplantation embryonic development have not been elucidated. By comparing RNA levels in different tissues, we found that Pum3 was widely expressed in multiple tissues, but moderately predominant in the ovary. Histochemical staining suggested that the PUM3 protein exhibits positive signals in oocytes, granulosa cells and theca cells of different follicle stages. Oocyte immunofluorescence results showed a slightly higher level of PUM3 protein in metaphase II compared with the germinal vesicle (GV) stage. After knockdown of Pum3 in GV oocytes using siRNA injection (siPUM3), no obvious defect was observed in the processes of GV breakdown and polar body extrusion during in vitro maturation (IVM) for the siPum3 oocytes. Compared with the control group, the siPUM3 group displayed no significant abnormality in the cleavage and blastocyst formation rate of these fertilized oocytes. Therefore, we can conclude that depletion of Pum3 does not affect mouse oocyte maturation and early embryonic development in vitro.

Pumilio3 ( Pum3 ) 是经典 RNA 结合蛋白 PUF（PUMILIO 和 FBF）家族成员的进化上较远的同源物，也通过转录后调节参与 RNA 代谢过程。然而， Pum3在小鼠卵母细胞成熟和植入前胚胎发育中的功能尚未阐明。通过比较不同组织中的RNA水平，我们发现Pum3广泛表达于多种组织中，但在卵巢中中等程度地表达。组织化学染色提示PUM3蛋白在不同卵泡阶段的卵母细胞、颗粒细胞和卵泡膜细胞中均表现出阳性信号。卵母细胞免疫荧光结果显示，与生发囊泡（GV）阶段相比，中期II阶段的PUM3蛋白水平略高。使用siRNA注射(siPUM3)敲低GV卵母细胞中的Pum3后， siPum3卵母细胞在体外成熟(IVM)过程中的GV分解和极体挤出过程中没有观察到明显缺陷。与对照组相比，siPUM3组的这些受精卵母细胞的卵裂和囊胚形成率没有表现出明显的异常。因此，我们可以得出结论， Pum3的缺失不会影响体外小鼠卵母细胞的成熟和早期胚胎发育。