Study On The Expression Of CDC14B During Bovine Oocyte Maturation And Early Embryonic Development

Cell devision cycle 14B (CDC14B) is a member of serine/threonine protein kinase family, which can reduce CDK activity in the mitotic of eukaryotes, and promote cell division and mitotic exit, therefore, CDC14B plays an important role in cell cycle regulation. This study examined the expression and localization of CDC14B in bovine oocyte maturation and early embryonic development. The results showed that the CDC14B mRNA and protein expression decreased in MⅡ when compared to GV during oocyte maturation. After fertilization, compared to MⅡ stage oocytes, the relative expression of CDC14B mRNA increased in 2-cell, 4-cell and 8-cell stage embryos, but still lower than that of GV stage. The CDC14B mRNA expression at blastocyst stage decreased to the lowest level. The dynamic change of CDC14B protein expression was increased in 2-cell stage, and decreased in 4-cell and 8-cell stages, while increased again in blastocyst. The location of CDC14B were detected in oocyte maturation and early embryonic development by immunofluorescence technique, results showed that CDC14B were dispersed in GV stage, and co-located with tubulin in MⅡ stages and AI-TI during oocyte maturation. After fertilization, CDC14B were located at the cell cortex, and cells contact part at 2-cell,4-cell,8-cell and blastocyst. CDC14B co-located with tubulin during meiosis suggested that it involved in oocyte meiotic division regulation, CDC14B located in cortex and cell contact part after fertilization suggested that it participated in mitosis regulation, and possible associated with cleavage of cytokinesis.In order to further study the mechanism of CDC14B, we constructed an over-expression vector of pCDC14B-cDNA-3.1(+), this vector were transfected into bovine fetal fibroblast cells by electroporation method. The RT-qPCR showed that CDC14B mRNA was transiently over-expressed in the transgenic cells, meanwhile, after transfected, cell growth became slowly, cell shape changed, and death cell number increased. These results showed that over-expression of CDC14B can affect the growth of bovine fetal fibroblasts.In summary, the expression and localization of CDC14B was changed dynamically during bovine oocyte maturation and early embryonic development, suggesting CDC14B involved in the regulation of cell division. The precise role of CDC14B in cell cycle regulation needs further studied.