Comparison of Ca2+ and CaMKII responses in IVF and ICSI in the mouse.
Novel methods of egg activation in human assisted reproductive technologies and animal somatic cell nuclear transfer are likely to alter the signalling process that occurs during normal fertilization. Intracytoplasmic sperm injection (ICSI) bypasses the normal processes of the acrosome reaction, sperm-egg fusion, and processing of the sperm plasma membrane, as well as alters some parameters of intracellular calcium ([Ca(2+)](i)) dynamics (reported previously by Kurokawa and Fissore (2003)). Herein, we extend these studies to determine if ICSI alters the activity of the Ca(2+)-dependent protein, Ca(2+)/calmodulin-dependent kinase II (CaMKII), which is responsible for the completion of meiosis in vertebrate eggs. After ICSI or in vitro fertilization (IVF), individual mouse eggs were monitored for their relative changes in both [Ca(2+)](i) and CaMKII activity during the first [Ca(2+)](i) rise and a subsequent rise associated with second polar body extrusion. The duration of the first [Ca(2+)](i) rise was greater in ICSI than in IVF, but the amplitude of the rise was transiently higher for IVF than ICSI. However, a similar mean CaMKII activity was observed in both procedures. During polar body extrusion, the amplitude and duration of the Ca(2+) rises were increased by a small amount in ICSI compared with IVF, whereas the CaMKII activities were similar. Thus, compared with IVF, ICSI is not associated with decreased or delayed CaMKII activity in response to these Ca(2+) signals in the mouse.
Markoulaki
Styliani
S
Sackler School of Biomedical Sciences, Program in Cell, Molecular, and Developmental Biology, Tufts University School of Medicine, Boston, MA 02111, USA.
Kurokawa
Manabu
M
Yoon
Sook-Young
SY
Matson
Sara
S
Ducibella
Tom
T
Fissore
Rafael
R
D000818:Animals; D020013:Calcium Signaling; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D010063:Ovum / Q000201:enzymology / Q000378:metabolism*; D020554:Sperm Injections, Intracytoplasmic; D013084:Sperm-Ovum Interactions; D013997:Time Factors
D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases