Testis-Specific Protein Y-Encoded (TSPY) Is Required for Male Early Embryo Development in Bos taurus.

Area of Science:

• Reproductive Biology
• Developmental Biology
• Genetics

Background:

• The testis-specific protein Y (TSPY) gene is crucial for male fertility and development.
• TSPY exhibits copy number variation (CNV) across species and individuals.
• Its role in early embryonic development is not well understood.

Purpose of the Study:

• To investigate the role of TSPY copy number variation (CNV) in male embryonic preimplantation development.
• To determine if TSPY CNV affects developmental competency and gene expression in early male embryos.

Main Methods:

• In vitro fertilization (IVF) using sex-sorted bull semen to create male embryos with varying TSPY CNV (1Y, 2Y, 3Y).
• Assessment of developmental competency (cleavage and blastocyst rates).
• Analysis of TSPY copy number, mRNA, and protein levels; TSPY RNA knockdown experiments.

Main Results:

• Blastocyst rates were significantly higher in the 3Y group (highest TSPY CNV).
• TSPY copy numbers varied significantly among groups (1Y: ~30, 2Y: ~33, 3Y: ~82).
• TSPY transcripts showed an inverse logarithmic pattern, with 3Y having significantly higher levels; TSPY protein was detected only in blastocysts.

Conclusions:

• TSPY CNV plays a role in male embryonic development, particularly affecting blastocyst formation.
• TSPY is essential for male embryo development beyond the eight-cell stage, as indicated by RNA knockdown studies.