Characterization of Polo-like kinase-1 in rat oocytes and early embryos implies its functional roles in the regulation of meiotic maturation, fertilization, and cleavage.
Polo-like kinase 1 (Plk1) is a family of serine/threonine protein kinases that play important regulatory roles during mitotic cell cycle progression. In this study, Plk1 expression, subcellular localization, and possible functions during rat oocyte meiotic maturation, fertilization, and embryonic cleavages were studied by using RT-PCR, Western blot, confocal microscopy, drug-treatments, and antibody microinjection. Both the mRNA and protein of this kinase were detected in rat maturing oocytes and developing embryos. Confocal microscopy revealed that Plk1 distributed abundantly in the nucleus at the germinal vesicle (GV) stage, was associated with spindle poles during the formation of M-phase spindle, and was translocated to the spindle mid-zone at anaphase. In fertilized eggs, Plk1 was strongly stained in the cytoplasm between the apposing male and female pronuclei, from where microtubules radiated. Throughout cytokinesis, Plk1 was localized to the division plane, both during oocyte meiosis and embryonic mitosis. The specific subcellular distribution of Plk1 was distorted after disrupting the M-phase spindle, while additional aggregation dots could be induced in the cytoplasm by taxol, suggesting its intimate association with active microtubule assembly. Plk1 antibody microinjection delayed the meiotic resumption and blocked the emission of polar bodies. In conclusion, Plk1 may be a multifunctional kinase that plays pivotal regulatory roles in microtubule assembly during rat oocyte meiotic maturation, fertilization, and early embryonic mitosis.
Fan
Heng-Yu
HY
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China.
Tong
Chao
C
Teng
Chun-Bo
CB
Lian
Li
L
Li
Shi-Wen
SW
Yang
Zeng-Ming
ZM
Chen
Da-Yuan
DY
Schatten
Heide
H
Sun
Qing-Yuan
QY
D000818:Animals; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002455:Cell Division; D002478:Cells, Cultured; D005314:Embryonic and Fetal Development / Q000235:genetics; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D018507:Gene Expression Regulation, Developmental; D008540:Meiosis; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology* / Q000201:enzymology*; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000097869:Polo-Like Kinase 1
D018797:Cell Cycle Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D000097869:Polo-Like Kinase 1