The Role Of HDAC3 During Mamalian Oocytes Maturation

Histone deacetylases(HDACs)have been shown to deacetylate numerous cellular substrates that govern a wide array of biological processes.HDAC3,a member of the Class I HDACs,is a highly conserved and ubiquitously expressed protein.However,its roles in meiotic oocytes are not known.To explore the role of HDAC3 in meiosis,we first examined its distribution at different stages of the mouse oocyte.HDAC3 is predominantly distributed in the nucleus of GV oocytes.However,accompanying meiotic resumption,HDAC3 resides in the cytoplasm and colocalized with the meiotic spindle.In the present study,we used the technique of siRNA specific extracorporeal knowdown HDAC3 expression in mouse oocytes.We find that mouse oocytes depleted of HDAC3 are unable to completely progress through meiosis,and are blocked at metaphase I stage.These HDAC3 knockdown oocytes show spindle/chromosome organization failure,with severely impaired kinetochore-microtubule attachments.Consistent with this,the level of BubRl,a central component of the spindle assembly checkpoint,at kinetochores is dramatically increased in metaphase oocytes following HDAC3 depletion.Dysregulated SAC is thought to be the major drivingforce of aneuploidy generation.The incidence of aneuploidy was accordingly increased in HDAC3-KD oocytes.HDAC3 K D resulted in a～3-to 4-fold increase in the incidence of aneuploidy eggs compared with controls.Knockdown and overexpression experiments reveal that HDAC3 modulates the acetylation status of a-tubulin in mouse oocytes.Importantly,the deacetylation mimetic mutant tubulin-K40R can partly rescue the defective phenotypes of HDAC3 knockdown oocytes.Our data support a model whereby HDAC3,through deacetylating tubulin,promotes microtubule stability and the establishment of kinetochore-microtubule interaction,consequently ensuring proper spindle morphology,accurate chromosome movement and orderly meiotic progression during oocyte maturation.Moreover,we used a selective HDAC3 inhibitor,RGFP966,exploring its role on porcine oocytes maturation and meiotic apparatus.We discover that RGFP966 caused the morphologic changes by displaying the incompact expansion of cumulus cells and the increased incidence of fragmentation.We found the special localization of HDAC3 in spindle-like pattern with accompany of meiosis resumption.HDAC3 inhibitor resulted in the maturation arrest with high rate of abnormal spindle morphology and misaligned chromosome.In line with this observation,confocal microscopy revealed that the acetylation level of a-tubulin is significantly increased in porcine oocytes.We conjecture the hyperacetylation of a-tubulin alters microtubule stability which might be associated with the defected phenotypes of RGFP966-treated oocytes.Taking together,these results demonstrated that HDAC3 had a novel role during porcine oocytes maturation.