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Updated: Aug 4, 2026

Mouse Sperm Cryopreservation and Recovery using the I·Cryo Kit
Published on: December 12, 2011
ICSI choreography: fate of sperm structures after monospermic rhesus ICSI and first cell cycle implications
J Ramalho-Santos1, P Sutovsky, C Simerly
1Oregon Regional Primate Research Center, Division of Reproductive Sciences, Beaverton, Oregon 97006, USA.
Abstract:
We have dissected the initial stages of fertilization by intracytoplasmic sperm injection of single spermatozoa into prime oocytes from fertile rhesus monkeys (Macaca mulatta). DNA decondensation was delayed at the apical portion of the sperm head. It is possible that this asynchronous male DNA decondensation could be related to the persistence of the sperm acrosome and perinuclear theca after injection. However, incomplete male pronuclear formation did not prevent sperm aster formation, microtubule nucleation and pronuclear apposition. In contrast, DNA synthesis was delayed in both pronuclei until the sperm chromatin fully decondensed, indicating that male pronuclear formation constitutes an important checkpoint during the first embryonic cell cycle.
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