Changes in protamine 1 distribution in human sperm nucleus during in vitro sperm-oocyte interaction: an immunoelectron microscopic study.
OBJECTIVE
To determine whether the process of sperm nuclear destabilization would begin before sperm-oocyte fusion in humans.


METHODS
Changes in the distribution of human protamine 1 were investigated in human spermatozoa from the ejaculate, in spermatozoa selected by swim-up or Percoll techniques, and in spermatozoa bound to zona pellucida (ZP) from oocytes that failed to fertilize in an IVF program.


METHODS
Center for Infertility and Assisted Reproductive Technology, and university departments.


METHODS
Fifteen couples undergoing an IVF program.


METHODS
Women underwent a similar superovulation induction protocol that consisted of GnRH agonist associated with hMG.


METHODS
Comparative immunoelectron microscopic study of sperm nucleus labeling with an anti-human protamine 1 specific protamine monoclonal antibody.


RESULTS
After selection by swim-up or by Percoll, spermatozoa show a significantly lower nuclear labeling than in the ejaculate. After binding to the ZP, labeling increases, more in spermatozoa selected by swim-up than by Percoll, but, after Percoll selection, labeling in zona-bound spermatozoa is lower than in the ejaculate.


CONCLUSIONS
In humans sperm binding to the ZP induces differences in the accessibility of the anti-human protamine 1 antibody, which are consistent with structural rearrangements of the DNA-nucleoproteins complex. These modifications must be a prelude to sperm decondensation, protamines replacement by histones, and subsequent reactivation of the sperm genome in the oocyte.
Colleu
D
D
Center for Infertility and Assisted Reproductive Technology La Sagesse, University of Rennes, France.
Lescoat
D
D
Thomas
D
D
Gouranton
J
J
D002467:Cell Nucleus / Q000737:chemistry*; D004247:DNA / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D016253:Microscopy, Immunoelectron; D011479:Protamines / Q000032:analysis*; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000737:chemistry*
C082073:PRM1 protein, human; D011479:Protamines; D004247:DNA