Pum3is dispensable for mouse oocyte maturation and embryo developmentin vitro

Abstract

SummaryPumilio3(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 ofPum3in mouse oocyte maturation and preimplantation embryonic development have not been elucidated. By comparing RNA levels in different tissues, we found thatPum3was 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 ofPum3in GV oocytes using siRNA injection (siPUM3), no obvious defect was observed in the processes of GV breakdown and polar body extrusion duringin vitromaturation (IVM) for thesiPum3oocytes. Compared with the control group, thesiPUM3group displayed no significant abnormality in the cleavage and blastocyst formation rate of these fertilized oocytes. Therefore, we can conclude that depletion ofPum3does not affect mouse oocyte maturation and early embryonic developmentin vitro.