evidence supports the involvement of nitric oxide (no) in a varity of male reproductive processes such as spermatogenesis, spermiogenesis, sperm motion, sperm metabolism and sperm capacitation. however, low concentration of no is essential in biology and physiology of spermatozoa, but high amounts of no is toxic and has negative effects on sperm functions. on the other hand, it is established t...

Several lines of evidence suggest that the telomere-associated protein TRF2 plays critical roles in the DNA damage response. TRF2 is rapidly and transiently phosphorylated by an ATM-dependent pathway in response to DNA damage and this DNA damage-induced phosphoryation is essential for the DNA-PK-dependent pathway of DNA double-strand break repair (DSB). However, the type of DNA damage that indu...