Page 92 - ESHRE2019

Overview
• Spermchromatinstructure
• Causes of sperm DNA damage • Tests for DNA fragmentation
• Effects on IVF outcomes
• What can be done?
• Conclusions
Sperm chromatins
Spermatid Spermatozoa Protamine s
Nucleosome (146bp)
s DNA Histone octamer
SolenoidChromatin condensation
Solenoid loop
Protamine‐DNA Toroid (Doughnut) (50‐100 kbp)
MAR: matrix attachment regions
for imprinting and development.
• Sensitive to oxidative damage
Ward WS (2010) MHR 16: 30–36.
Kocer et al. (2015) Free Radic Biol Med. 89:993–1002.
Folded histone Solenoid (15%)
(Dnase1•sNenosinti‐vrea)ndomly distributed
• Associated with promoter of genes
• 15% histone‐DNA is retained. Toroid Linker MAR
Nuclear matrix
Protamine‐ DNA Toroid
Ward WS (2018) Am J Clin Exp Urol. 6:87‐92. Hammoud et al. (2009) Nature 460: 473
• Strong +ve charged proteins  form a condensed complex with strong ‐ve charge DNA
• Formation of S‐S bonds between protamines stabilize the nucleoprotamine complex
90
86