Localization and function of mSpindly during mouse oocyte meiotic maturation.
Spindly was first identified in Drosophila; its homologues are termed SPDL-1 in Caenorhabditis elegans and Hs Spindly/hSpindly in humans. In all species, Spindly and its homologues function by recruiting dynein to kinetochores and silencing SAC in mitosis of somatic cells. Depletion of Spindly causes an extensive metaphase arrest during somatic mitoses in Drosophila, C. elegans and humans. In Drosophila, Spindly is required for shedding of Rod and Mad2 from the kinetochores in metaphase; in C. elegans, SPDL-1 presides over the recruitment of dynein and MDF-1 to the kinetochores; in humans, Hs Spindly is required for recruiting both dynein and dynactin to kinetochores but it is dispensable for removal of checkpoint proteins from kinetochores. The present study was designed to investigate the localization and function of the Spindly homologue (mSpindly) during mouse oocyte meiotic maturation by immunofluorescent analysis, and by overexpression and knockdown of mSpindly. We found that mSpindly was typically localized to kinetochores when chromatin condensed into chromosomes after GVBD. In metaphase of both first meiosis and second meiosis, mSpindly was localized not only to kinetochores but also to the spindle poles. Overexpression of mSpindly did not affect meiotic progression, but its depletion resulted in an arrest of the pro-MI/MI stage, failure of anaphase entry and subsequent polar body emission, and in abnormal spindle morphology and misaligned chromosomes. Our data suggest that mSpindly participates in SAC silencing and in spindle formation as a recruiter and/or a transporter of kinetochore proteins in mouse oocytes, but that it needs to cooperate with other factors to fulfill its function.
Zhang
Qing-Hua
QH
College of Life Sciences, Shandong Normal University, Jinan, Shandong, China.
Wei
Liang
L
Tong
Jing-Shan
JS
Qi
Shu-Tao
ST
Li
Sen
S
Ou
Xiang-Hong
XH
Ouyang
Ying-Chun
YC
Hou
Yi
Y
An
Li-Gou
LG
Schatten
Heide
H
Schatten
Heide
H
Sun
Qing-Yuan
QY
D000818:Animals; D018797:Cell Cycle Proteins / Q000032:analysis* / Q000378:metabolism / Q000502:physiology; D020223:Chromosome Painting; D018386:Kinetochores / Q000378:metabolism; D008540:Meiosis; D008677:Metaphase; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000032:analysis* / Q000378:metabolism / Q000502:physiology; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism / Q000502:physiology
D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D016271:Proto-Oncogene Proteins c-myc; C560870:Spindly protein, mouse