Phosphorylation of histone H3 on Serl0 by auto-phosphorylated PAK1 is not essential for chromatin condensation and meiotic progression in porcine oocytes

摘要

Background: The p21-activated kinase 1 (PAK1) is essential for mitosis and plays an important role in the regulation of microtubule assembly during oocyte meiotic maturation in mice; however, little is known about its role in porcine oocytes. Result: Total p21-activated kinase 1 (PAK1) and phosphorylated PAK1 at Thr423 (PAK1 Thr423 ) were consistently expressed in porcine oocytes from the germinal vesicle (GV) to the second metaphase (MII) stages, but phosphorylation of histone H3 at Ser10 (H3 Ser10 ) was only expressed after the GV stage. Immunofluorescence analysis revealed that PAK1 Thr423 and H3 Ser10 colocalized on chromosomes after the GV stage. Blocking of endogenous PAK1 Thr423 by injecting a specific antibody decreased the phosphorylation level of H3 Ser10 ; however, it had no impact on chromatin condensation, meiotic progression, cleavage rate of blastomeres or the rate of blastocyst formation. Conclusion: Phosphorylation of PAK1 Thr423 is a spontaneous activation process and the activated PAK1 Thr423 can promote the phosphorylation of H3 Ser10 ; however, this pathway is not required for meiotic maturation of porcine oocytes or early embryonic development.