TY - JOUR
T1 - The role of protein kinase C in reorganization of the cortical cytoskeleton during the transition from oocyte to fertilization‐competent egg
AU - Capco, David
AU - Tutnick, J. M.
AU - Bement, W. M.
PY - 1992/12/15
Y1 - 1992/12/15
N2 - Fertilization‐competent amphibian eggs (metaphase II) are programmed to undergo an actin‐myosin based contraction of the cortical cytoplasm (i.e., cortical contraction) in response to an elevation of intracellular‐free calcium which accompanies fertilization. This ability to undergo cortical contraction is acquired within a few hours after the meiotically‐arrested oocyte is triggered to resume meiosis by exposure to progesterone. This report examines the timing of changes in the contractile potential of the cortical cytoplasm as the oocyte becomes the egg, and in addition, the signal transduction events which induce these changes. We use the bisected oocyte system developed by Christensen et al. ('84; Nature 310: 150‐151) to assess the changes in cortical potential during the meiotic resumption. Immediately after progesterone treatment (less than 5% of the way through the meiotic resumption) the cortex acquires the ability to form a contractile ring, an ability which gradually disappears during the meiotic resumption. Eighty percent of the way through the meiotic resumption the cortex of the hemisphere rapidly acquires the ability to undergo cortical contraction. In contrast, when bisected in a medium containing protein kinase C (PKC) agonists, the cortex of the hemisphere undergoes cortical contraction much earlier (i.e., 50% through the meiotic resumption). In addition, treatment of oocytes with PKC agonists alone can mimic the complete spectrum of changes in cortical potential induced by progesterone, suggesting that PKC has a role in reorganization of the cortical cytoskeleton which occurs as a normal response to progesterone. In support of this, antagonists of PKC block the progesterone‐induced reorganization of the cortical cytoskeleton. © 1992 Wiley‐Liss, Inc.
AB - Fertilization‐competent amphibian eggs (metaphase II) are programmed to undergo an actin‐myosin based contraction of the cortical cytoplasm (i.e., cortical contraction) in response to an elevation of intracellular‐free calcium which accompanies fertilization. This ability to undergo cortical contraction is acquired within a few hours after the meiotically‐arrested oocyte is triggered to resume meiosis by exposure to progesterone. This report examines the timing of changes in the contractile potential of the cortical cytoplasm as the oocyte becomes the egg, and in addition, the signal transduction events which induce these changes. We use the bisected oocyte system developed by Christensen et al. ('84; Nature 310: 150‐151) to assess the changes in cortical potential during the meiotic resumption. Immediately after progesterone treatment (less than 5% of the way through the meiotic resumption) the cortex acquires the ability to form a contractile ring, an ability which gradually disappears during the meiotic resumption. Eighty percent of the way through the meiotic resumption the cortex of the hemisphere rapidly acquires the ability to undergo cortical contraction. In contrast, when bisected in a medium containing protein kinase C (PKC) agonists, the cortex of the hemisphere undergoes cortical contraction much earlier (i.e., 50% through the meiotic resumption). In addition, treatment of oocytes with PKC agonists alone can mimic the complete spectrum of changes in cortical potential induced by progesterone, suggesting that PKC has a role in reorganization of the cortical cytoskeleton which occurs as a normal response to progesterone. In support of this, antagonists of PKC block the progesterone‐induced reorganization of the cortical cytoskeleton. © 1992 Wiley‐Liss, Inc.
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U2 - 10.1002/jez.1402640405
DO - 10.1002/jez.1402640405
M3 - Article
C2 - 1460437
AN - SCOPUS:0027121310
SN - 0022-104X
VL - 264
SP - 395
EP - 405
JO - Journal of Experimental Zoology
JF - Journal of Experimental Zoology
IS - 4
ER -