Mouse strain-dependent egg factors regulate calcium signals at fertilization

Area of Science:

• Reproductive Biology
• Developmental Biology
• Cellular Physiology

Background:

• Fertilization triggers calcium (Ca2+) signals essential for cell cycle resumption and embryonic development.
• In mammals, sperm phospholipase Cζ induces Ca2+ release from the endoplasmic reticulum (ER), creating oscillatory patterns modulated by egg factors.

Purpose of the Study:

• To compare Ca2+ oscillation characteristics and ER Ca2+ stores following in vitro fertilization (IVF) across nine common laboratory mouse strains.
• To investigate the influence of egg-intrinsic factors on Ca2+ dynamics during fertilization.

Main Methods:

• In vitro fertilization (IVF) using sperm from B6SJLF1/J males across nine different mouse strains.
• Analysis of Ca2+ oscillation patterns, including duration, amplitude, frequency, and ER Ca2+ stores.

Main Results:

• Significant variations were observed among mouse strains in the duration and amplitude of the first Ca2+ transient, oscillation frequency, and ER Ca2+ stores.
• With a constant male strain, differences in Ca2+ oscillation patterns were attributed to variations in egg factors among the mouse strains.

Conclusions:

• Egg-intrinsic properties play a critical role in determining Ca2+ oscillation patterns during fertilization.
• These findings have significant implications for the interpretation and comparison of studies investigating Ca2+ dynamics at fertilization across different mouse models.