Differential expression of the Oct-4 transcription factor during mouse germ cell differentiation

Abstract

The POU transcription factor Oct-4 is expressed in early mouse embryogenesis and in pluripotent ES and EC stem cell lines. After gastrulation in the embryo, Oct-4 expression is confined to the germline. The present study provides evidence that Oct-4 undergoes downregulation during oogenesis and spermatogenesis, coincident with entry into meiosis. Furthermore, analysis of maturation stages of oocytes showed that Oct-4 is upregulated de novo in the final stages of meiotic prophase I in female germ cells. These data suggest that Oct-4 downregulation in germ cells in both sexes might represent one of the molecular triggers involved in the commitment to meiosis. The upregulation of Oct-4 in oocytes at the completion of the prophase I of meiotic division further suggests a specific involvement of this transcription factor in oocyte growth or the acquisition of meiotic competence.

Stem cell pluripotency and transcription factor Oct4

“…Indeed, Oct4 is expressed by germ cells from the totipotent zygote to the highly specialized oocyte [9], [20], [21]. It is likely that Oct4 may function in concert with other regulators to activate specific target genes in specific cell types at defined developmental stages.…”

“…In the mouse, Oct4 mRNA is present in mature oocytes [20]. At the eightcell stage, Oct4 expression reaches a much higher level [21].…”

“…Subsequently, Oct4 expression becomes restricted to the ICM, and is downregulated in the TE and primitive endoderm (see Fig 1) [21]. Later on in embryo development, Oct4 expression is only maintained in primordial germ cells (PGCs) [9,20]. Hansis et al examined Oct4 expression in human blastocysts.…”

GDNF Signaling Regulates YBX1/mRNA Interactions in Mouse Spermatogonia.

“…Transcription factors, such as PLZF, OCT4 and SOHLH2, which are unique to undifferentiated germ cells, have all been studied as facilitators of SSC function [115][116][117][118][119][120]. Furthermore, many groups have used microarray analysis to identify SSC transcripts in vivo and in SSC culture [121][122][123][124].…”

Productionin vitrode cellules germinales murines et humaines à partir de cellules souches pluripotentes

“…La différenciation ovocytaire la plus complète a été obtenue à partir de mCSE par expression forcée (transfert de gènes) des facteurs Oct4 ou Gdf9 chez la souris. Le facteur Oct4, exprimé dans les cellules pluripotentes, est réexprimé dans les ovocytes en croissance après leur arrêt en méiose I ; son expression reste faible au cours des derniers stades de la maturation ovocytaire [26]. Dans des mCSE, Hubner et al ont réalisé une expression ciblée d'Oct4 (gcOct4-GFP) puis, après sélection et culture d'une rare population coexprimant GFP et Kit, ont obtenu une population cellulaire exprimant des marqueurs spécifiques de la lignée germinale tels Gdf9 et Scp3 [27].…”