Alterations of PLCbeta1 in mouse eggs change calcium oscillatory behavior following fertilization.
Inositol 1,4,5-trisphosphate generated by the action of a phospholipase C (PLC) mediates release of intracellular Ca2+ that is essential for sperm-induced activation of mammalian eggs. Much attention currently focuses on the role of sperm-derived PLCzeta in generating changes in egg intracellular Ca2+ despite the fact that PLCzeta constitutes a very small fraction of the total amount of PLC in a fertilized egg. Eggs express several isoforms of PLC, but a role for an egg-derived PLC in sperm-induced Ca2+ oscillations has not been examined. Reducing egg PLCbeta1 by a transgenic RNAi approach resulted in a significant decrease in Ca2+ transient amplitude, but not duration or frequency, following insemination. Furthermore, overexpressing PLCbeta1 by microinjecting a Plcb1 cRNA significantly perturbed the duration and frequency of Ca2+ transients and disrupted the characteristic shape of the first transient. These results provide the first evidence for a role of an egg-derived PLC acting in conjunction with a sperm-derived PLCzeta in egg activation.
Igarashi
Hideki
H
Center for Research on Reproduction and Women's Health, University of Pennsylvania, Philadelphia, PA 19104, USA.
Knott
Jason G
JG
Schultz
Richard M
RM
Williams
Carmen J
CJ
D000818:Animals; D020013:Calcium Signaling; D004622:Embryo, Mammalian / Q000166:cytology / Q000201:enzymology; D047108:Embryonic Development; D005260:Female; D005306:Fertilization; D007527:Isoenzymes / Q000378:metabolism; D008164:Luminescent Proteins; D008297:Male; D008540:Meiosis; D051379:Mice; D018345:Mice, Knockout; D009865:Oocytes / Q000166:cytology / Q000201:enzymology; D010063:Ovum / Q000166:cytology / Q000201:enzymology*; D010641:Phenotype; D054799:Phospholipase C beta / Q000378:metabolism*; D013094:Spermatozoa; D013997:Time Factors; D000097573:Red Fluorescent Protein
D007527:Isoenzymes; D008164:Luminescent Proteins; D054799:Phospholipase C beta; D000097573:Red Fluorescent Protein; C518034:Plcb1 protein, mouse