A novel atypical sperm centriole is functional during human fertilization

Area of Science:

• Cell Biology
• Reproductive Biology
• Human Fertilization

Background:

• Centrosome inheritance during human fertilization is poorly understood.
• The sperm centrosome comprises a proximal centriole (PC), pericentriolar material (PCM), and an atypical distal centriole (DC).

Purpose of the Study:

• To elucidate the structure and function of the sperm centrosome, particularly the distal centriole (DC).
• To investigate the remodeling of the sperm centrosome during spermatogenesis and its role in fertilization.

Main Methods:

• In vivo and in vitro investigations were employed.
• Analysis included examining protein composition, structural remodeling, and functional capabilities of the sperm centrosome.

Main Results:

• The sperm centrosome undergoes remodeling, including protein reduction/enrichment and formation of novel rods within the DC.
• The atypical DC, attached to the flagellum, can recruit PCM, form a daughter centriole, and localize to the spindle pole during mitosis.
• The DC is compositionally and structurally remodeled into the zygote's second functional centriole.

Conclusions:

• The distal centriole (DC) is a key, remodeled component of the sperm centrosome, functioning as the zygote's second centriole.
• These findings offer new diagnostic and therapeutic targets for male infertility and early embryo developmental defects.
• Understanding sperm centrosome dynamics provides insights into early human development.