Trypsin-like Hatching Enzyme of Mouse Blastocysts: Evidence for Its Participation in Hatching Process before Zona...

Area of Science:

• Reproductive biology
• Developmental biology
• Biochemistry

Background:

• Embryo hatching is a critical step in mammalian reproduction.
• The specific enzymes and mechanisms regulating mouse embryo hatching are not fully understood.
• Protease activity is suspected to play a role in the hatching process.

Purpose of the Study:

• To investigate the role of proteases in mouse embryo hatching.
• To identify the type of protease involved in hatching.
• To determine the precise timing of the hatching enzyme's activity during the hatching process.

Main Methods:

• Treatment of mouse embryos with twelve different protease inhibitors.
• Assessing the effect of inhibitors on embryo hatching.
• Pulse treatment with a specific trypsin inhibitor (TLCK) at different developmental stages.

Main Results:

• Trypsin inhibitors, including p-toluenesulfonyl-Lys-CH2 Cl (TLCK) and chicken ovomucoid, strongly inhibited mouse embryo hatching.
• Inhibitors targeting chymotrypsin and elastase showed minimal or no effect on hatching.
• The trypsin-like hatching enzyme is active prior to, but not during, zona shedding, particularly in the 15 hours preceding it.

Conclusions:

• A trypsin-like protease functions as the key hatching enzyme in mouse embryos.
• The activity of this hatching enzyme is essential for the pre-hatching stages.
• Understanding the timing of hatching enzyme activity provides insights into early embryonic development and reproductive processes.