A spindle assembly checkpoint protein functions in prophase I arrest and prometaphase progression.
Two critical stages of mammalian oocyte regulation are prophase I arrest, which is important for sustaining the oocyte pool, and the progression through meiosis I (MI) to produce fertilizable eggs. We have found that the spindle assembly checkpoint protein BubR1 regulates both stages in mouse oocytes. We show that oocytes depleted of BubR1 cannot sustain prophase I arrest and readily undergo germinal vesicle breakdown, a marker for reentry into MI. BubR1-depleted oocytes then arrest before completing MI, marked by failure of polar body extrusion. Both meiotic defects in BubR1-depleted oocytes are due to reduced activity of the master regulator known as the anaphase-promoting complex (APC), brought about through diminished levels of the APC coactivator Cdh1.
Homer
Hayden
H
Oocyte and Embryo Research Laboratory, Department of Cell and Developmental Biology, Division of Biosciences and Institute for Women's Health, University College London, London, UK. h.homer@ucl.ac.uk
Gui
Liming
L
Carroll
John
J
D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D064199:Cdc20 Proteins; D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D056744:Cyclin B1 / Q000378:metabolism; D005260:Female; D020868:Gene Silencing; D008540:Meiosis / Q000502:physiology*; D049469:Meiotic Prophase I / Q000502:physiology*; D051379:Mice; D009865:Oocytes / Q000502:physiology*; D049468:Prometaphase / Q000502:physiology* / Q000528:radiation effects*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D064249:Securin; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism
C584278:Bub1b protein, mouse; D002352:Carrier Proteins; C534700:Ccnb1 protein, mouse; D064199:Cdc20 Proteins; C577491:Cdc20 protein, mouse; D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins; D056744:Cyclin B1; C577585:Fzr1 protein, mouse; D064249:Securin; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases