Effects of activation on functional aster formation, microtubule assembly, and blastocyst development of goat oocytes injected with round spermatids.
A systematic study was conducted on round spermatids (ROS) injection (ROSI) using the goat model. After ROSI, the oocytes were treated or not with ionomycin (ROSI+I and ROSI-I, respectively) and compared with intracytoplasmic sperm injection (ICSI). After ROSI-I, most oocytes were arrested with premature chromatin condensation and few oocytes formed pronuclei. In contrast, most oocytes formed pronuclei after ROSI+I. Some ROS were observed to form asters that organized a dense microtubule network after ROSI+I, but after ROSI-I, no ROS asters were observed. Whereas most of the oocytes showed Ca(2+) rises and a significant decline in maturation-promoting factor (MPF) and mitogen-activated protein kinase (MAPK) activities after ROSI+I, no such changes were observed after ROSI-I. Due to the lack of Ca(2+) oscillations after ROSI-I, oocytes were injected with more ROS. Interestingly, different from the results observed in a single ROS injection, injection with four ROS effectively activated oocytes by inducing typical Ca(2+) oscillations. Whereas ROSI+I oocytes and ICSI oocytes both showed extensive microtubule networks, no such a network was observed in parthenogenetic oocytes. Together, the results suggest that goat ROS is not able to trigger intracellular Ca(2+) rises and thus to inhibit MPF and MAPK activities, but artificial activation improved fertilization and development of ROSI goat oocytes. Goat ROS can organize functional microtubular asters in activated oocytes. A ROS-derived factor(s) may be essential for organization of a functional microtubule network to unite pronuclei. Goat centrosome is of paternal origin because both ROS and sperm asters organized an extensive microtubule network after intra-oocyte injection.
College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai-an City, P.R. China.
Xin-Yong
XY
Liu
Yi-Long
YL
Miao
Jie
J
Zhang
Jian-Hua
JH
Qiu
Xiang-Zhong
XZ
Cui
Wei-Qiang
WQ
Gao
Ming-Jiu
MJ
Luo
Jing-He
JH
Tan
D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D002118:Calcium / Q000378:metabolism; D006041:Goats; D015759:Ionomycin / Q000494:pharmacology; D008297:Male; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000187:drug effects; D009865:Oocytes / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013084:Sperm-Ovum Interactions; D013087:Spermatids
D017382:Reactive Oxygen Species; D015759:Ionomycin; D002118:Calcium